Longevity Wiki - User contributions [en-GB]

Cryonics

2021-09-08T16:19:10Z

BLife: /* Cryonics Organizations */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>
[[File:Patient long term care bay at Alcor.jpg|thumb|The patient long term care bay at Alcor Life Extension Foundation, circa 2020.]]
Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it is unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==The Cost of Cryonics==

Cryonics is typically paid for using life insurance. As of 2020, the cost of a cryopreservation procedure is $80,000 at [https://alcor.org/ Alcor], or $28,000 at the [https://www.cryonics.org/ Cryonics Institute], or $18,000 at [http://kriorus.ru/en KrioRus]. (These prices are not directly comparable, because the features of the cryonics plans are different at each organization, including the options for standby and stabilization services.) The majority of people do not pay for cryopreservation "out of pocket". They typically pay for cryonics using a life insurance policy, which tends to make cryonics services more affordable. For example, the cost of a suitable term life insurance policy for a healthy middle-aged adult might be a few hundred dollars per year. The full cryopreservation costs are not due until the time of death, which is why cryonics services can generally be paid with a life insurance policy.

It is common for cryonics clients to purchase a term or permanent life policy with a face value of $250,000. (This policy size is also commonly offered by insurance companies.) As of 2019, a policy of this amount is more than sufficient to pay for a standard cryonics plan from any known cryonics organization, with significant funds remaining for other desired beneficiaries.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==Cryonics Organizations==

===Cryonics Storage Organizations===

* [https://www.alcor.org/ Alcor Life Extension Foundation], Cryonics Storage Organization, in Scottsdale AZ, USA.
* [https://www.cryonics.org/ Cryonics Institute], Cryonics Storage Organization, in Clinton Township MI, USA.
* [https://kriorus.ru/en KrioRus], Cryonics Storage Organization, in Moscow, Russia.

===Stabilization and Transport Companies===

* [https://suspendedanimationlabs.com/ Suspended Animation, Inc], Cryonics Stabilization and Transport Company, operating within the continental USA.

===Information and Advocacy===

* [https://www.longecity.org/ LongeCity], Information and Advocacy for Cryonics and Life Extension.

===New Organizations and Projects===

* [https://southerncryonics.com/ Southern Cryonics], A Cryonics Storage Organization constructing a new cryonics storage facility, in New South Wales, Australia. They are projected to open in 2022.

==References==
<references />
[[Category:Longevity]]

Handbook:Meeting Minutes

2021-09-08T10:56:03Z

BLife: /* 08/09/2021 */

== 08/09/2021 ==

🧍 Attending
* Jack Harley
* Blake Delaney
* Marc Smeehuijzen
* Bogdan Dziewierz

=== 📣 Updates ===
''Blake Delaney''

* Introduction: hedge fund manager, with programming, and bioscience background. Previously created a longevity wiki but did not gain traction at the time

* Wikipedia doesn't have the highest quality on longevity and cryonics topics as those with higher override capability often prevent a thorough review of the topic
* Media Wiki has the functionality for authors to be notified when their articles are updated - this can be applied to our project
* Created a 'Cryonics' page on the Wiki - should we keep it on the Wiki? Consensus was yes.
* Social funding could be used to raise funding for the Wiki
* Suggest he can fund AWS infrastructure
* Create a Lifespan.io project and pitch our organization to them to attract funding
* Crowdfunding on the Discord server
* Interested in joining the engineering team and will try to make it to this week's meeting
* Can support a member to create an application to register for a US charity
* There is significant work involved in maintaining charity status
* Alternatively, operate as an LLC and avoid most tax liability by spending as much as you earn
* Some US states have very minimal reporting requirements for LLCs.

''Marc''

* How should we provide feedback to each other's article?

* Discussion page makes sense for feedback to specific articles
* Benefit of our Wiki is that it allows for more speculative topics than Wikipedia, such as longevity science and cryonics

''Jack''

* Provided update on content writers meeting
* Block updates to 'Pillar' articles once completed to avoid vandalism
* Can keep the 'cryonics' page on the Wiki, though, pending reaching out to science and medical organizations for content writing

''Sharon Wong''

* Have a header that says, 'version active as of (date)' on multilingual pages to overcome the issue of translated articles requiring frequent updates
* Having issues uploading the image on the rapamycin article - @Bogdan to investigate
* Style and standardising translating terms into Chinese requires a standard glossary
* There is a need to stipulate the translation tool for those who are translating the wiki (e.g. DeepL)
* Need for the 'how to contribute' page on the Wiki Handbook to be updated with translation tasks.
* Higher bar for 'tax deductible status' in Australia. It's a good reason to avoid this for now, to avoid excessive paperwork.

''Bogdan''

* Will have to create 'drafts' namespace
* 'Discussion' page associated with pages on the Wiki is currently active
* Discussion page can foster more discussion amongst non-Discord users of the Wiki
* Cryonics discussion brings up an interesting point - what is the included scope of the Wiki? Consensus was that anything 'life-span extending' related should be included. In particular topics that Wikipedia doesn't cover well.
* Updated the onboarding guide for new developers
* Life extension tool in-progress
* Sam Voigt has previously volunteered to pursue the pros and cons of registering as a non-for-profit - @Jack to get in touch
* UK may have a separate charity status to receive money if no goods or services (business-like activities)

== 01/09/2021 ==

=== 🧍 Attending ===

* Jack Harley
* Ben Wu
* Sharon Wong
* Marc Smeehuijzen
* Andreas Melhede

=== 📣 Updates ===
''Jack Harley''

* Begun ''Aging and Neurodegeneration'' brainstorm and write-up. References and comments welcome.
* Collaborated with Max to create process for content writers (discussed below)
* Kindly ask all Wiki members to complete [https://docs.google.com/forms/d/e/1FAIpQLScnXVdwTutWe_xNt6wJMPoXu_v9QBLb1A7QrBXRXXBifUyESg/viewform?usp=send_form volunteer form] to help keep a record
* [https://agingpharma.org/ ARDD Conference] has begun - good opportunity for Wiki members to learn more about the field - videos should be uploaded to the website for free viewing in the coming weeks.
* Goal is to have 4 pillar articles - by Max, Jack, Ben and the Rapamycin articles - by the end of September 2021

''Sharon Wong''

* Noted that the translation for the Rapamycin article was updating while
* Found it difficult to quickly copy content and formatting to a new page - Bogdan may able to assist with this
* Noted that it's probably not worth translating references
* Recommended deepl.com as the 'gold standard' for translating of articles. Produces more simplistic sentence structures compared to Google Translate.

''Ben Wu''

* Summary of EARD conference - mentioned Tina Woods' talk on lobbying UK government to increase funding towards aging research, and recognising biology of aging as a critical healthcare mission. Also mentioned that emphasis on healthspan seems more effective in communication than emphasis on lifespan.

''Marc''

* Bi-weekly content writers meetings could be structured around a review process whereby writers provide helpful feedback on other writers' articles. Maybe writers with journalistic/editor experience know of an effective review process similar to how people work at a newspaper/magazine/journal.
* We should prevent information being copied across various parts of the website because this makes maintenance harder. E.g. the 'About us' information is now both on the About us page and in the Handbook. He suggests removing the 'About Us' content from the Handbook, and replace it with a link to the 'About us' page.
* The handbook contains much valuable information for contributors but is not that interesting for most wiki visitors who just visit the wiki for longevity related information. He suggests to show only some high level 'how to contribute' information on the 'How to contribute' page so we don't overwhelm visitors (basically just asking people to contact us if they want to help) and then add a prominent link to the Handbook for if they want to dive into all the details.<br />

Andreas Melhede:

* Discussed Discord Role Management on Discord with Stuart McWhinney.
** It is very close to finished and ready to be implemented on our server.

''Max Schulz:''

* Trello Board Set-up & Organization (Tasks on Wiki I would consider once further in development)
** Let's focus only on trello boards that are used, and archive others - I propose:
*** Archiving ''Engineering'' and ''UX'' -> Moving to Jira
*** Merging ''Marketing'' & ''Operations Infrastructure'' into Organisational '''(Please move the tasks you find relevant and archive these)'''
*** Using ''Organisational'' board to manage weekly core meetings
*** Using ''Content creators'' board to manage (to be scheduled) bi-weekly content creators meeting
*** Overall: Can we have one trello group/team with several boards instead of inviting separately for each board? (Should be possible with members instead of guests? [[https://trello.com/en/pricing Pricing Info] | [https://help.trello.com/article/1236-board-guests Board Guests Info]])
** ''Organisational'' board (people need to be added):
*** Should be reviewed and kept up to date weekly
*** Action items should be created as tasks, if applicable - I tried to add most of them, sometimes people have to be assigned again
*** I propose even if task is technical (e.g. making handbook more prominent [https://trello.com/c/fOFtXUmy Trello card]) but relevant to the organisational meetings, it should also be tracked on Trello
*** Proposed board usage:
**** Future ideas for clearly far in the future (months)
**** Backlog for tasks to do soon (weeks)
**** Todo for tasks agreed to be done next, or you want to work on next
**** Once task is worked on -> Move to In Progress
**** If you want someone to review -> Move to In Review
**** If task is done -> Move to Done, can then be shared in the next weekly meeting and archived
** Task hygiene we should agree on ([https://mnschulz.medium.com/managing-work-in-a-startup-e80a3d122620 Personal article]), examples:
*** Meaningful task definitions
*** Assigned doesn't necessarily mean the person does all the work, but takes (especially on the communication side) responsibility
** Side-remark: Tipp to see your cards - [https://help.trello.com/article/819-viewing-all-of-your-cards Trello Help]
* Content writer management:
** Low-hanging fruit for article organisation: Instead of just alphabetic ordering in [[Articles]], can we have groups of articles with the first "Category" as the ordering? (Or another mechanism in Mediawiki?) I think it would be important to separate "Pillar Articles", "General Articles" and "Glossary" already for the management of the articles
** Temporary content writer sheet: [https://docs.google.com/spreadsheets/d/1e9djbjXdMV7m4655yjIISHRoUpB_1mbJcv0O8Zwj1fg/edit#gid=0 link] - will be superseeded by volunteer survey responses (see below)
** Wrote update to content writers [https://docs.google.com/document/d/1FlD9sTf5fPGhBiWYHV9nhzr0ucO6n4CFfEzcdbtnfC0/edit (text link)] with doodle survey for first bi-weekly content meeting after summer (note: should have set a deadlien for doodle ...^^)
**''Content creators'' board:
*** Pillar article label added (also to introductory article, which can be vital as well)
***'''Process for bi-weekly meeting has to be figured out (round-table style?)'''
* Jack created the volunteer survey, ([https://docs.google.com/forms/d/1An8sOTXi_Hne3Elmp1sY1n-3fr6PXwf-bUgPBi8X6e0/edit edit link]) - [https://forms.gle/KHmveeaRSgamtr1D7 shareable link] | answers are linked to the [https://docs.google.com/spreadsheets/d/1FDFYQhQVBdDdHEiGqY1pif0T7sd-suRwOK-0wl7AIXU Google Sheet]
** Should be filled out by all team members so we have an overview.

== 25/08/2021 ==

=== 🧍 Attending ===

* Jack Harley
* Bogdan Dziewierz
* Marc Smeehuijzen
* Ben Wu
* Andreas Melhede
* Heye Groß
* Max Schons
* Stuart

=== 📣 Updates ===
* Considering scoring of new participants to determine level of understanding, also as filtering for determining what level they might contribute at
* Thinking about providing a list of articles/content etc for Wiki contributors to obtain a better overview of the field
* Database of interests of participants, time zones etc.
* Max Schons working on risk factors, subjective vs objective measures of health, various major disease
* Considering submitting core articles to professional proofreading agencies, or reaching out to undergrad/postgrad students
* Heye planning on engaging with EA community at conferences and talking about the Wiki
* Technical meeting bimonthly with Bogdan, Mac, Stuart
* Considering merging Max's medium article with Ben's intro article

{| class="wikitable"
|
=== ✅ Action Items ===

* Continue working on core articles
*
|}

== 18/08/2021 ==

=== 🧍 Attending ===
* Jack Harley
* Bogdan Dziewierz
* Max Schulz
* Andreas Melhede
* Sam Voigt
* Marc Smeehujizen
* Heye Groß

=== 📣 Updates Roundtable ===
Jack Harley

* India times article is being finalised, to be released next week or week after. New co-author [https://medicine.nus.edu.sg/bch/faculty/brian-kennedy/ Brian Kennedy] joined

* More contributors interested to join the project. There is a need for people to help with on-boarding new contributors

* Gave a talk in EA group in Melbourne. This was followed up with an invitation to the medical conference in Melbourne.

* Handbook work is progressing'''.''' We need to make it more prominent and visible in the menu.

''Bogdan Dziewierz''

* Custom namespace "Handbook" created on the Wiki
* Engineering iteration meeting needs to be scheduled. Created new #engineering channel in Discord to help with coordination of such activities.
* Slowly progressing on Life Extension tool

''Heye Groß''

* Will get more involved in Longevity Wiki over next weeks. More clear on working hours.
* Discussed whether Longevity is a topic that is / should be on the agenda for EA compared to other existential risks and how EA can be used as spread-the-word or funding platform for Longevity effectively.
* Open Philantropy: Donates to the most effective areas but have a pessimistic view of longevity research. We think their evaluation is limited because they haven’t done cost / benefits calculation of investing into geroscience. Can be low-hanging fruit for donations, provided cost / benefit calculation is done for them.

''Jack Harley''

* Let’s try to organise symposium or conference once we get funding. EA could be convinced to fund this initiative.

''Max Schulz''

* Meeting Organization in general: I also like the process of always having a pre-created meeting topics from participants file for the next meeting
** Every participant plan can add his points already (I personally like to do this), then the meeting owner already has an idea in advance what people want to talk about and how to potentially structure it (Jack Harley in this case?)
* Updated the about page with pillar articles and ongoing projects suggestion ([[Handbook:Handbook]]). Some open points on my side (see page)
** 5 or 20 pillar articles to start with? Saw conflicting information
** Content should be merged with: [[About]], [[How to contribute]] (Especially "Other Roles")
** In the visual editor, there are quite some "paragraphs" that I can't delete, they don't show up in the source editor ...?
** Open calendar links for meetings would be good (also are there other meetings to know of...?)
* How do you currently navigate the articles on the wiki? For example, how do you find the handbook article? (Any ongoing efforts on the navigation side?)
* There are article drafts shared on Discord with Google Docs, we should encourage everybody to directly write to the Wiki so this work doesn't get lost (e.g. [https://docs.google.com/document/d/1gSJjEJbP_A1Qs_uewoWjkSFUhsyfN1IUNUYIVuxDb7E/edit link]) (The "core articles" that we want to work on should just be categorized accordingly IMHO)
** Similarly, with the glossary suggestion - better if it would be already added to the wiki instead: [https://docs.google.com/document/d/1q2dlsLK76bAXyU3ZPZ_eWn_oI3UFQEtie_8D2nRH5cQ/edit#heading=h.lhdrp4ijtcd2 google docs]
* What is the status of the vision and action plan? ([https://docs.google.com/presentation/d/1rlPZyncQGRW6koCunM23msQyVWEQ0CVyGMnMAUSaE8U/edit#slide=id.g655cbd83be_0_18 Google Slides])
* Idea to try get some funding from the upcoming Gitcoin round from VitaDAO? I know that the high quality articles would make the case stronger, on the other hand they explicitly want to also go for early projects and "open science": [https://docs.google.com/document/d/13rjnkgxCdQ63V1M69cE-moeY6ktRfo5XIF8E9nwaeIU/edit Quadratic Funding Round Document]
* Last week, the process of registering a non-profit was quickly discussed but it's not in the minutes (I don't remember what was discussed)

''Heye Groß / Jack Harley / Bogdan Dziewierz''

* There is need to think about what we need money for so that we can start participating in funding rounds / grants / etc.

''Andres Melhede''

* Waiting for India article so that it can be used as a source for more content to be used on Social Media

{| class="wikitable"
|
=== ✅ Action Items ===

* Jack: There is a need for volunteers to help with on-boarding new contributors

* Bogdan: We need to make it more prominent and visible in the menu
* Bogdan: How to contribute menu item needs to be replaced with Handbook
* Jack: We need to brainstorm and document what we need the funds for so that we can start participating in funding rounds / grants / etc.
* Jack: Let’s try to organise symposium or conference once we get funding.
* Max: Max to follow up with VitaDAO to find out if we can participate in their Gitcoin round.
|}

== 11/08/2021 ==

=== Purpose ===
Regular weekly meeting

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Bogdan Dziewierz, Co-founder & Head of Engineering
* Max Schons, Content Writer
* Max Schulz, Engineering Team Member and Organisational Consultant
* Ben Wu, Head of Content
* Andreas Melhede, Head of Marketing
* Sharon Wong, Content Translator

=== 📣 Updates Roundtable ===

# Name: Max Schulz
## Discussed benefits of the ‘handbook-first’ approach, such as convenience in onboarding new volunteers to the organisation, and having a centralized knowledge base for strategy and roadmap documents. Brought up the need for a central landing page upon which organisational links are easily accessible.
## Discussed platforms for hosting the Handbook, such as Confluence.
# Name Bogdan
## Suggested using the Wiki itself as the ‘Handbook’, and Confluence for the engineering activities. The rest of the team agreed. Offered to create a namespace using MediaWiki for the handbook and landing page.
## Life extension tool is a work in progress.
# Name Jack
## Discussed the role of content writer manager, and suggested Max Schulz be introduced to this role.
## Once content writers are on board with the new content writing strategy, those with a biology background can be tasked with adding data to the life extension tool.
# ‍Name Max Schons
## Outlined briefly the content strategy of creating a few high quality articles then seeking the endorsement of experts in the field, to attract more high quality contributors.
## Provided example of meeting minutes layouts in a handbook: <nowiki>https://github.com/mermaid-js/mermaid/releases</nowiki>
# Name Ben
## Provided update on the Times of India article, which will be published in the coming 1-2 weeks. The article will mention Longevity Wiki in the authors’ biographies section.
# Name Sharon
## Offered to review meeting minutes, and provided suggestions for the minutes - including key references and links at the beginning of the minutes.
# Name Andreas
## Provided updates on social media accounts.
## Did several edits and suggestions for the Aging Article for the Indian News Site.

{| class="wikitable"
|
=== ✅ Action Items ===

* Bogdan to create namespace for Handbook, and Handbook landing page
* Jack follow up on Max’s organizational wiki suggestions
* Jack to follow up with Max Schulz regarding content writers management
* Jack to assign organizational document writing to other members
* Bogdan to organize an Engineering team spring meeting
* Jack to create and share a document of organizational processes
* Max Schulz to forward exemplary handbook to Jack
* Max Schons to continue working on Biomarkers of Healthspan article
* Ben Wu to continue working on Aging Epigenetics article
|}

== 04/08/2021 ==

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Bogdan Dziewierz, Co-founder & Head of Engineering
* Marc Smeehuijzen, Head of UX
* Ben Wu, Head of Content
* Andreas Melhede, Head of Marketing

=== 📣 Updates Roundtable ===

# Name: Bogdan
## Had the kick-off engineering meeting 30 July 2021 with Sam Voigt, Maximilian Schulz and Mark Whitlock. He setup Jira and Confluence. (These are popular project management tools in IT development). The engineering cards on Trello will be moved to Jira. For more details on this meeting, see the minutes on Confluence. (If you don’t have access to Confluence, ask Bogdan).
## Suggestion: split weekly meetings per department (so engineering, marketing, content, etc. all have their own weekly meeting instead of everybody in the same meeting).
## Suggestion: we could move the draft articles that we’re working on from Google Docs to the wiki itself. This way visitors can see the wiki is alive and check recent changes of the articles.
## Continue working on the Life Extension Tool and a glossary extension for the wiki, among other things. We might develop other tools in the future. Jack for instance suggested an interactive roadmap for longevity laboratories in the world.
# Name Ben
## There is a little delay in writing the India Times article on longevity. But it’s 90% done. He will see if we can get a famous professor as co author (e.g. David Sinclair). On Google Docs there’s a draft of the article and members of the team are welcome to provide feedback
# Name Jack
## Talked to Maximillian Schulz who made a number of interesting organizational suggestions for the wiki (see Jack’s email from 4 Aug. 2021). There is a need for organizational docs to be made transparently accessible on the Wiki, and we proposed this be in the form of pages on the Wiki categorized accordingly.
## New marketing expert is interested in joining the project, could work alongside Andreas
## Plan to reach out to expert in Rapamycin (Mikhail Blagosklonny) to seek a review/endorsement for this article on the Wiki.
## Looking for someone who can manage the content writers.
# ‍Name Marc
## Updated the design for the Life Extension Tool. There are now two modes: 1. you can see per species what % life extension has been achieved per intervention and 2. you can see per intervention what % life extension has been achieved per species. The designs can be found on Zeplin. (If you don’t have access to Zeplin, please send Marc your email address so he can add you). He also posted some screenshots of the designs in the UX channel on our Discord server.
## Made English to Dutch translations of the interface elements of the wiki (document is on Google Drive).
# Name Andreas
## Made some social media posts on the 5 key articles that we’re working on.
## Engagement and sharing relevant content on the various social media platforms (especially focused on Twitter)

{| class="wikitable"
|
=== ✅ Action Items ===

* Ben looks for famous professor as co author for India Times article
* Jack follow up on Maximillian’s organizational wiki suggestions
* Jack looks for someone to manage the content writers
* Jack to assign organizational document writing to other members
* Marc joins the engineering team and moves his Trello cards to Jira
|}

== 29/07/2021 ==

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Andreas Melhede, Head of Marketing
* Ben Wu, Head of Content

=== 🙌 Celebrate wins ===

* New software developer, Mark Whitlock, will join the IT team to help develop the technical side
* Database for the Life Extension Tool (the UX design for which can be viewed here) has been created

=== 💬 Discussion Topics ===

* Who are we trying to target with content? Discussed the need for content that appeals to the masses to fill a gap in content in this space. While we hope to create content that scientists will read, and for credibility most will likely stick with reading review articles so we should bear in mind our target audience of non-specialists.

=== 📣 Updates Roundtable ===

# Name: Jack
## A new contributor, Max Schultz, who has written blog posts about knowledge databases has provided a report on the state of the Wiki, offering avenues for expanding the Wiki. The notes for his meeting agenda with me are attached below this document.
## We have created an excel spreadsheet of data for the Life extension tool, and are encouraging contributors to help expand the data.
## Have created a new folder in the Google Drive called ‘Weekly Meetings’ wherein this Meeting Minutes and future minutes can be saved.
## Discussed the need to update content writers with a new approach of creating a glossary for pillar articles.
# Name Ben
## Joao Pedro’s database contains an extensive list of drugs and their life extension effects, which we can draw from for our own tool. <nowiki>https://genomics.senescence.info/drugs/browse.php</nowiki>

<nowiki>https://genomics.senescence.info/drugs/</nowiki>

We should aim to create a more user-friendly, and simplified version for our tool, focusing on ~20 key drugs that are most relevant to today’s life extension protocols.

# We should focus on data from the ITP (NIA’s Intervention Testing Program) as this is a rigorous and reliable test.

# Name Andreas
## Clarifying the target audience as primarily those who are non-specialists
## Clarified the style of social media posts, as evidence-based and reliable, as advised by Ben.

‍
{| class="wikitable"
|
=== ✅ Action Items ===

* Jack meeting with Max Shulz to discuss further collaboration ideas
* Ben to add list of drugs of interest to lifespan extension tool database
* Ben to add relevant sources to the database for content writers - E.g. ITP
* Assign content writers / other team members with science background to assist with completing data for the life extension tool
* Andreas to create Discord channel for meeting minutes
* Communicate to content writers the new deliverables of expanding the glossary associated with the ‘pillar’ articles
|}

Handbook:Meeting Minutes

2021-09-08T10:53:54Z

BLife: /* 📣 Updates */

== 08/09/2021 ==

🧍 Attending
* Jack Harley
* Blake Delaney
* Marc Smeehuijzen
* Bogdan Dziewierz

=== 📣 Updates ===
''Blake Delaney''

* Introduction: hedge fund manager, previously created a longevity wiki but did not gain traction at the time

* Wikipedia doesn't have the highest quality on longevity and cryonics topics as those with higher override capability often prevent a thorough review of the topic
* Media Wiki has the functionality for authors to be notified when their articles are updated - this can be applied to our project
* Created a 'Cryonics' page on the Wiki - should we keep it on the Wiki? Consensus was yes.
* Social funding could be used to raise funding for the Wiki
* Suggest he can fund AWS infrastructure
* Create a Lifespan.io project and pitch our organization to them to attract funding
* Crowdfunding on the Discord server
* Interested in joining the engineering team and will try to make it to this week's meeting
* Can support a member to create an application to register for a US charity
* There is significant work involved in maintaining charity status
* Alternatively, operate as an LLC and avoid most tax liability by spending as much as you earn
* Some US states have very minimal reporting requirements for LLCs.

''Marc''

* How should we provide feedback to each other's article?

* Discussion page makes sense for feedback to specific articles
* Benefit of our Wiki is that it allows for more speculative topics than Wikipedia, such as longevity science and cryonics

''Jack''

* Provided update on content writers meeting
* Block updates to 'Pillar' articles once completed to avoid vandalism
* Can keep the 'cryonics' page on the Wiki, though, pending reaching out to science and medical organizations for content writing

''Sharon Wong''

* Have a header that says, 'version active as of (date)' on multilingual pages to overcome the issue of translated articles requiring frequent updates
* Having issues uploading the image on the rapamycin article - @Bogdan to investigate
* Style and standardising translating terms into Chinese requires a standard glossary
* There is a need to stipulate the translation tool for those who are translating the wiki (e.g. DeepL)
* Need for the 'how to contribute' page on the Wiki Handbook to be updated with translation tasks.
* Higher bar for 'tax deductible status' in Australia. It's a good reason to avoid this for now, to avoid excessive paperwork.

''Bogdan''

* Will have to create 'drafts' namespace
* 'Discussion' page associated with pages on the Wiki is currently active
* Discussion page can foster more discussion amongst non-Discord users of the Wiki
* Cryonics discussion brings up an interesting point - what is the included scope of the Wiki? Consensus was that anything 'life-span extending' related should be included. In particular topics that Wikipedia doesn't cover well.
* Updated the onboarding guide for new developers
* Life extension tool in-progress
* Sam Voigt has previously volunteered to pursue the pros and cons of registering as a non-for-profit - @Jack to get in touch
* UK may have a separate charity status to receive money if no goods or services (business-like activities)

== 01/09/2021 ==

=== 🧍 Attending ===

* Jack Harley
* Ben Wu
* Sharon Wong
* Marc Smeehuijzen
* Andreas Melhede

=== 📣 Updates ===
''Jack Harley''

* Begun ''Aging and Neurodegeneration'' brainstorm and write-up. References and comments welcome.
* Collaborated with Max to create process for content writers (discussed below)
* Kindly ask all Wiki members to complete [https://docs.google.com/forms/d/e/1FAIpQLScnXVdwTutWe_xNt6wJMPoXu_v9QBLb1A7QrBXRXXBifUyESg/viewform?usp=send_form volunteer form] to help keep a record
* [https://agingpharma.org/ ARDD Conference] has begun - good opportunity for Wiki members to learn more about the field - videos should be uploaded to the website for free viewing in the coming weeks.
* Goal is to have 4 pillar articles - by Max, Jack, Ben and the Rapamycin articles - by the end of September 2021

''Sharon Wong''

* Noted that the translation for the Rapamycin article was updating while
* Found it difficult to quickly copy content and formatting to a new page - Bogdan may able to assist with this
* Noted that it's probably not worth translating references
* Recommended deepl.com as the 'gold standard' for translating of articles. Produces more simplistic sentence structures compared to Google Translate.

''Ben Wu''

* Summary of EARD conference - mentioned Tina Woods' talk on lobbying UK government to increase funding towards aging research, and recognising biology of aging as a critical healthcare mission. Also mentioned that emphasis on healthspan seems more effective in communication than emphasis on lifespan.

''Marc''

* Bi-weekly content writers meetings could be structured around a review process whereby writers provide helpful feedback on other writers' articles. Maybe writers with journalistic/editor experience know of an effective review process similar to how people work at a newspaper/magazine/journal.
* We should prevent information being copied across various parts of the website because this makes maintenance harder. E.g. the 'About us' information is now both on the About us page and in the Handbook. He suggests removing the 'About Us' content from the Handbook, and replace it with a link to the 'About us' page.
* The handbook contains much valuable information for contributors but is not that interesting for most wiki visitors who just visit the wiki for longevity related information. He suggests to show only some high level 'how to contribute' information on the 'How to contribute' page so we don't overwhelm visitors (basically just asking people to contact us if they want to help) and then add a prominent link to the Handbook for if they want to dive into all the details.<br />

Andreas Melhede:

* Discussed Discord Role Management on Discord with Stuart McWhinney.
** It is very close to finished and ready to be implemented on our server.

''Max Schulz:''

* Trello Board Set-up & Organization (Tasks on Wiki I would consider once further in development)
** Let's focus only on trello boards that are used, and archive others - I propose:
*** Archiving ''Engineering'' and ''UX'' -> Moving to Jira
*** Merging ''Marketing'' & ''Operations Infrastructure'' into Organisational '''(Please move the tasks you find relevant and archive these)'''
*** Using ''Organisational'' board to manage weekly core meetings
*** Using ''Content creators'' board to manage (to be scheduled) bi-weekly content creators meeting
*** Overall: Can we have one trello group/team with several boards instead of inviting separately for each board? (Should be possible with members instead of guests? [[https://trello.com/en/pricing Pricing Info] | [https://help.trello.com/article/1236-board-guests Board Guests Info]])
** ''Organisational'' board (people need to be added):
*** Should be reviewed and kept up to date weekly
*** Action items should be created as tasks, if applicable - I tried to add most of them, sometimes people have to be assigned again
*** I propose even if task is technical (e.g. making handbook more prominent [https://trello.com/c/fOFtXUmy Trello card]) but relevant to the organisational meetings, it should also be tracked on Trello
*** Proposed board usage:
**** Future ideas for clearly far in the future (months)
**** Backlog for tasks to do soon (weeks)
**** Todo for tasks agreed to be done next, or you want to work on next
**** Once task is worked on -> Move to In Progress
**** If you want someone to review -> Move to In Review
**** If task is done -> Move to Done, can then be shared in the next weekly meeting and archived
** Task hygiene we should agree on ([https://mnschulz.medium.com/managing-work-in-a-startup-e80a3d122620 Personal article]), examples:
*** Meaningful task definitions
*** Assigned doesn't necessarily mean the person does all the work, but takes (especially on the communication side) responsibility
** Side-remark: Tipp to see your cards - [https://help.trello.com/article/819-viewing-all-of-your-cards Trello Help]
* Content writer management:
** Low-hanging fruit for article organisation: Instead of just alphabetic ordering in [[Articles]], can we have groups of articles with the first "Category" as the ordering? (Or another mechanism in Mediawiki?) I think it would be important to separate "Pillar Articles", "General Articles" and "Glossary" already for the management of the articles
** Temporary content writer sheet: [https://docs.google.com/spreadsheets/d/1e9djbjXdMV7m4655yjIISHRoUpB_1mbJcv0O8Zwj1fg/edit#gid=0 link] - will be superseeded by volunteer survey responses (see below)
** Wrote update to content writers [https://docs.google.com/document/d/1FlD9sTf5fPGhBiWYHV9nhzr0ucO6n4CFfEzcdbtnfC0/edit (text link)] with doodle survey for first bi-weekly content meeting after summer (note: should have set a deadlien for doodle ...^^)
**''Content creators'' board:
*** Pillar article label added (also to introductory article, which can be vital as well)
***'''Process for bi-weekly meeting has to be figured out (round-table style?)'''
* Jack created the volunteer survey, ([https://docs.google.com/forms/d/1An8sOTXi_Hne3Elmp1sY1n-3fr6PXwf-bUgPBi8X6e0/edit edit link]) - [https://forms.gle/KHmveeaRSgamtr1D7 shareable link] | answers are linked to the [https://docs.google.com/spreadsheets/d/1FDFYQhQVBdDdHEiGqY1pif0T7sd-suRwOK-0wl7AIXU Google Sheet]
** Should be filled out by all team members so we have an overview.

== 25/08/2021 ==

=== 🧍 Attending ===

* Jack Harley
* Bogdan Dziewierz
* Marc Smeehuijzen
* Ben Wu
* Andreas Melhede
* Heye Groß
* Max Schons
* Stuart

=== 📣 Updates ===
* Considering scoring of new participants to determine level of understanding, also as filtering for determining what level they might contribute at
* Thinking about providing a list of articles/content etc for Wiki contributors to obtain a better overview of the field
* Database of interests of participants, time zones etc.
* Max Schons working on risk factors, subjective vs objective measures of health, various major disease
* Considering submitting core articles to professional proofreading agencies, or reaching out to undergrad/postgrad students
* Heye planning on engaging with EA community at conferences and talking about the Wiki
* Technical meeting bimonthly with Bogdan, Mac, Stuart
* Considering merging Max's medium article with Ben's intro article

{| class="wikitable"
|
=== ✅ Action Items ===

* Continue working on core articles
*
|}

== 18/08/2021 ==

=== 🧍 Attending ===
* Jack Harley
* Bogdan Dziewierz
* Max Schulz
* Andreas Melhede
* Sam Voigt
* Marc Smeehujizen
* Heye Groß

=== 📣 Updates Roundtable ===
Jack Harley

* India times article is being finalised, to be released next week or week after. New co-author [https://medicine.nus.edu.sg/bch/faculty/brian-kennedy/ Brian Kennedy] joined

* More contributors interested to join the project. There is a need for people to help with on-boarding new contributors

* Gave a talk in EA group in Melbourne. This was followed up with an invitation to the medical conference in Melbourne.

* Handbook work is progressing'''.''' We need to make it more prominent and visible in the menu.

''Bogdan Dziewierz''

* Custom namespace "Handbook" created on the Wiki
* Engineering iteration meeting needs to be scheduled. Created new #engineering channel in Discord to help with coordination of such activities.
* Slowly progressing on Life Extension tool

''Heye Groß''

* Will get more involved in Longevity Wiki over next weeks. More clear on working hours.
* Discussed whether Longevity is a topic that is / should be on the agenda for EA compared to other existential risks and how EA can be used as spread-the-word or funding platform for Longevity effectively.
* Open Philantropy: Donates to the most effective areas but have a pessimistic view of longevity research. We think their evaluation is limited because they haven’t done cost / benefits calculation of investing into geroscience. Can be low-hanging fruit for donations, provided cost / benefit calculation is done for them.

''Jack Harley''

* Let’s try to organise symposium or conference once we get funding. EA could be convinced to fund this initiative.

''Max Schulz''

* Meeting Organization in general: I also like the process of always having a pre-created meeting topics from participants file for the next meeting
** Every participant plan can add his points already (I personally like to do this), then the meeting owner already has an idea in advance what people want to talk about and how to potentially structure it (Jack Harley in this case?)
* Updated the about page with pillar articles and ongoing projects suggestion ([[Handbook:Handbook]]). Some open points on my side (see page)
** 5 or 20 pillar articles to start with? Saw conflicting information
** Content should be merged with: [[About]], [[How to contribute]] (Especially "Other Roles")
** In the visual editor, there are quite some "paragraphs" that I can't delete, they don't show up in the source editor ...?
** Open calendar links for meetings would be good (also are there other meetings to know of...?)
* How do you currently navigate the articles on the wiki? For example, how do you find the handbook article? (Any ongoing efforts on the navigation side?)
* There are article drafts shared on Discord with Google Docs, we should encourage everybody to directly write to the Wiki so this work doesn't get lost (e.g. [https://docs.google.com/document/d/1gSJjEJbP_A1Qs_uewoWjkSFUhsyfN1IUNUYIVuxDb7E/edit link]) (The "core articles" that we want to work on should just be categorized accordingly IMHO)
** Similarly, with the glossary suggestion - better if it would be already added to the wiki instead: [https://docs.google.com/document/d/1q2dlsLK76bAXyU3ZPZ_eWn_oI3UFQEtie_8D2nRH5cQ/edit#heading=h.lhdrp4ijtcd2 google docs]
* What is the status of the vision and action plan? ([https://docs.google.com/presentation/d/1rlPZyncQGRW6koCunM23msQyVWEQ0CVyGMnMAUSaE8U/edit#slide=id.g655cbd83be_0_18 Google Slides])
* Idea to try get some funding from the upcoming Gitcoin round from VitaDAO? I know that the high quality articles would make the case stronger, on the other hand they explicitly want to also go for early projects and "open science": [https://docs.google.com/document/d/13rjnkgxCdQ63V1M69cE-moeY6ktRfo5XIF8E9nwaeIU/edit Quadratic Funding Round Document]
* Last week, the process of registering a non-profit was quickly discussed but it's not in the minutes (I don't remember what was discussed)

''Heye Groß / Jack Harley / Bogdan Dziewierz''

* There is need to think about what we need money for so that we can start participating in funding rounds / grants / etc.

''Andres Melhede''

* Waiting for India article so that it can be used as a source for more content to be used on Social Media

{| class="wikitable"
|
=== ✅ Action Items ===

* Jack: There is a need for volunteers to help with on-boarding new contributors

* Bogdan: We need to make it more prominent and visible in the menu
* Bogdan: How to contribute menu item needs to be replaced with Handbook
* Jack: We need to brainstorm and document what we need the funds for so that we can start participating in funding rounds / grants / etc.
* Jack: Let’s try to organise symposium or conference once we get funding.
* Max: Max to follow up with VitaDAO to find out if we can participate in their Gitcoin round.
|}

== 11/08/2021 ==

=== Purpose ===
Regular weekly meeting

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Bogdan Dziewierz, Co-founder & Head of Engineering
* Max Schons, Content Writer
* Max Schulz, Engineering Team Member and Organisational Consultant
* Ben Wu, Head of Content
* Andreas Melhede, Head of Marketing
* Sharon Wong, Content Translator

=== 📣 Updates Roundtable ===

# Name: Max Schulz
## Discussed benefits of the ‘handbook-first’ approach, such as convenience in onboarding new volunteers to the organisation, and having a centralized knowledge base for strategy and roadmap documents. Brought up the need for a central landing page upon which organisational links are easily accessible.
## Discussed platforms for hosting the Handbook, such as Confluence.
# Name Bogdan
## Suggested using the Wiki itself as the ‘Handbook’, and Confluence for the engineering activities. The rest of the team agreed. Offered to create a namespace using MediaWiki for the handbook and landing page.
## Life extension tool is a work in progress.
# Name Jack
## Discussed the role of content writer manager, and suggested Max Schulz be introduced to this role.
## Once content writers are on board with the new content writing strategy, those with a biology background can be tasked with adding data to the life extension tool.
# ‍Name Max Schons
## Outlined briefly the content strategy of creating a few high quality articles then seeking the endorsement of experts in the field, to attract more high quality contributors.
## Provided example of meeting minutes layouts in a handbook: <nowiki>https://github.com/mermaid-js/mermaid/releases</nowiki>
# Name Ben
## Provided update on the Times of India article, which will be published in the coming 1-2 weeks. The article will mention Longevity Wiki in the authors’ biographies section.
# Name Sharon
## Offered to review meeting minutes, and provided suggestions for the minutes - including key references and links at the beginning of the minutes.
# Name Andreas
## Provided updates on social media accounts.
## Did several edits and suggestions for the Aging Article for the Indian News Site.

{| class="wikitable"
|
=== ✅ Action Items ===

* Bogdan to create namespace for Handbook, and Handbook landing page
* Jack follow up on Max’s organizational wiki suggestions
* Jack to follow up with Max Schulz regarding content writers management
* Jack to assign organizational document writing to other members
* Bogdan to organize an Engineering team spring meeting
* Jack to create and share a document of organizational processes
* Max Schulz to forward exemplary handbook to Jack
* Max Schons to continue working on Biomarkers of Healthspan article
* Ben Wu to continue working on Aging Epigenetics article
|}

== 04/08/2021 ==

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Bogdan Dziewierz, Co-founder & Head of Engineering
* Marc Smeehuijzen, Head of UX
* Ben Wu, Head of Content
* Andreas Melhede, Head of Marketing

=== 📣 Updates Roundtable ===

# Name: Bogdan
## Had the kick-off engineering meeting 30 July 2021 with Sam Voigt, Maximilian Schulz and Mark Whitlock. He setup Jira and Confluence. (These are popular project management tools in IT development). The engineering cards on Trello will be moved to Jira. For more details on this meeting, see the minutes on Confluence. (If you don’t have access to Confluence, ask Bogdan).
## Suggestion: split weekly meetings per department (so engineering, marketing, content, etc. all have their own weekly meeting instead of everybody in the same meeting).
## Suggestion: we could move the draft articles that we’re working on from Google Docs to the wiki itself. This way visitors can see the wiki is alive and check recent changes of the articles.
## Continue working on the Life Extension Tool and a glossary extension for the wiki, among other things. We might develop other tools in the future. Jack for instance suggested an interactive roadmap for longevity laboratories in the world.
# Name Ben
## There is a little delay in writing the India Times article on longevity. But it’s 90% done. He will see if we can get a famous professor as co author (e.g. David Sinclair). On Google Docs there’s a draft of the article and members of the team are welcome to provide feedback
# Name Jack
## Talked to Maximillian Schulz who made a number of interesting organizational suggestions for the wiki (see Jack’s email from 4 Aug. 2021). There is a need for organizational docs to be made transparently accessible on the Wiki, and we proposed this be in the form of pages on the Wiki categorized accordingly.
## New marketing expert is interested in joining the project, could work alongside Andreas
## Plan to reach out to expert in Rapamycin (Mikhail Blagosklonny) to seek a review/endorsement for this article on the Wiki.
## Looking for someone who can manage the content writers.
# ‍Name Marc
## Updated the design for the Life Extension Tool. There are now two modes: 1. you can see per species what % life extension has been achieved per intervention and 2. you can see per intervention what % life extension has been achieved per species. The designs can be found on Zeplin. (If you don’t have access to Zeplin, please send Marc your email address so he can add you). He also posted some screenshots of the designs in the UX channel on our Discord server.
## Made English to Dutch translations of the interface elements of the wiki (document is on Google Drive).
# Name Andreas
## Made some social media posts on the 5 key articles that we’re working on.
## Engagement and sharing relevant content on the various social media platforms (especially focused on Twitter)

{| class="wikitable"
|
=== ✅ Action Items ===

* Ben looks for famous professor as co author for India Times article
* Jack follow up on Maximillian’s organizational wiki suggestions
* Jack looks for someone to manage the content writers
* Jack to assign organizational document writing to other members
* Marc joins the engineering team and moves his Trello cards to Jira
|}

== 29/07/2021 ==

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Andreas Melhede, Head of Marketing
* Ben Wu, Head of Content

=== 🙌 Celebrate wins ===

* New software developer, Mark Whitlock, will join the IT team to help develop the technical side
* Database for the Life Extension Tool (the UX design for which can be viewed here) has been created

=== 💬 Discussion Topics ===

* Who are we trying to target with content? Discussed the need for content that appeals to the masses to fill a gap in content in this space. While we hope to create content that scientists will read, and for credibility most will likely stick with reading review articles so we should bear in mind our target audience of non-specialists.

=== 📣 Updates Roundtable ===

# Name: Jack
## A new contributor, Max Schultz, who has written blog posts about knowledge databases has provided a report on the state of the Wiki, offering avenues for expanding the Wiki. The notes for his meeting agenda with me are attached below this document.
## We have created an excel spreadsheet of data for the Life extension tool, and are encouraging contributors to help expand the data.
## Have created a new folder in the Google Drive called ‘Weekly Meetings’ wherein this Meeting Minutes and future minutes can be saved.
## Discussed the need to update content writers with a new approach of creating a glossary for pillar articles.
# Name Ben
## Joao Pedro’s database contains an extensive list of drugs and their life extension effects, which we can draw from for our own tool. <nowiki>https://genomics.senescence.info/drugs/browse.php</nowiki>

<nowiki>https://genomics.senescence.info/drugs/</nowiki>

We should aim to create a more user-friendly, and simplified version for our tool, focusing on ~20 key drugs that are most relevant to today’s life extension protocols.

# We should focus on data from the ITP (NIA’s Intervention Testing Program) as this is a rigorous and reliable test.

# Name Andreas
## Clarifying the target audience as primarily those who are non-specialists
## Clarified the style of social media posts, as evidence-based and reliable, as advised by Ben.

‍
{| class="wikitable"
|
=== ✅ Action Items ===

* Jack meeting with Max Shulz to discuss further collaboration ideas
* Ben to add list of drugs of interest to lifespan extension tool database
* Ben to add relevant sources to the database for content writers - E.g. ITP
* Assign content writers / other team members with science background to assist with completing data for the life extension tool
* Andreas to create Discord channel for meeting minutes
* Communicate to content writers the new deliverables of expanding the glossary associated with the ‘pillar’ articles
|}

Handbook:Meeting Minutes

2021-09-08T10:50:26Z

BLife: spelling correction

== 08/09/2021 ==

🧍 Attending
* Jack Harley
* Blake Delaney
* Marc Smeehuijzen
* Bogdan Dziewierz

=== 📣 Updates ===
''Blake Delaney''

* Introduction: hedge fund manager, previously created a longevity wiki but did not gain traction at the time

* Wikipedia doesn't have the highest quality on longevity and cryonics topics as those with higher override capability often prevent a thorough review of the topic
* Media Wiki has the functionality for authors to be notified when their articles are updated - this can be applied to our project
* Created a 'Cryonics' page on the Wiki - should we keep it on the Wiki? Consensus was yes.
* Social funding could be used to raise funding for the Wiki
* Suggest he can fund AWS infrastructure
* Create a Lifespan.io project and pitch our organization to them to attract funding
* Crowdfunding on the Discord server
* Interested in joining the engineering team and will try to make it to this week's meeting
* Can support a member to create an application to register for a US charity
* There is significant work involved in maintaining charity status
* Alternatively, operate as an LLC and avoid most tax liability by spending as much as you earn
* Some states have very minimal reporting requirements

''Marc''

* How should we provide feedback to each other's article?

* Discussion page makes sense for feedback to specific articles
* Benefit of our Wiki is that it allows for more speculative topics than Wikipedia, such as longevity science and cryonics

''Jack''

* Provided update on content writers meeting
* Block updates to 'Pillar' articles once completed to avoid vandalism
* Can keep the 'cryonics' page on the Wiki, though, pending reaching out to science and medical organizations for content writing

''Sharon Wong''

* Have a header that says, 'version active as of (date)' on multilingual pages to overcome the issue of translated articles requiring frequent updates
* Having issues uploading the image on the rapamycin article - @Bogdan to investigate
* Style and standardising translating terms into Chinese requires a standard glossary
* There is a need to stipulate the translation tool for those who are translating the wiki (e.g. DeepL)
* Need for the 'how to contribute' page on the Wiki Handbook to be updated with translation tasks.
* Higher bar for 'tax deductible status' in Australia. It's a good reason to avoid this for now, to avoid excessive paperwork.

''Bogdan''

* Will have to create 'drafts' namespace
* 'Discussion' page associated with pages on the Wiki is currently active
* Discussion page can foster more discussion amongst non-Discord users of the Wiki
* Cryonics discussion brings up an interesting point - what is the included scope of the Wiki? Consensus was that anything 'life-span extending' related should be included. In particular topics that Wikipedia doesn't cover well.
* Updated the onboarding guide for new developers
* Life extension tool in-progress
* Sam Voigt has previously volunteered to pursue the pros and cons of registering as a non-for-profit - @Jack to get in touch
* UK may have a separate charity status to receive money if no goods or services (business-like activities)

== 01/09/2021 ==

=== 🧍 Attending ===

* Jack Harley
* Ben Wu
* Sharon Wong
* Marc Smeehuijzen
* Andreas Melhede

=== 📣 Updates ===
''Jack Harley''

* Begun ''Aging and Neurodegeneration'' brainstorm and write-up. References and comments welcome.
* Collaborated with Max to create process for content writers (discussed below)
* Kindly ask all Wiki members to complete [https://docs.google.com/forms/d/e/1FAIpQLScnXVdwTutWe_xNt6wJMPoXu_v9QBLb1A7QrBXRXXBifUyESg/viewform?usp=send_form volunteer form] to help keep a record
* [https://agingpharma.org/ ARDD Conference] has begun - good opportunity for Wiki members to learn more about the field - videos should be uploaded to the website for free viewing in the coming weeks.
* Goal is to have 4 pillar articles - by Max, Jack, Ben and the Rapamycin articles - by the end of September 2021

''Sharon Wong''

* Noted that the translation for the Rapamycin article was updating while
* Found it difficult to quickly copy content and formatting to a new page - Bogdan may able to assist with this
* Noted that it's probably not worth translating references
* Recommended deepl.com as the 'gold standard' for translating of articles. Produces more simplistic sentence structures compared to Google Translate.

''Ben Wu''

* Summary of EARD conference - mentioned Tina Woods' talk on lobbying UK government to increase funding towards aging research, and recognising biology of aging as a critical healthcare mission. Also mentioned that emphasis on healthspan seems more effective in communication than emphasis on lifespan.

''Marc''

* Bi-weekly content writers meetings could be structured around a review process whereby writers provide helpful feedback on other writers' articles. Maybe writers with journalistic/editor experience know of an effective review process similar to how people work at a newspaper/magazine/journal.
* We should prevent information being copied across various parts of the website because this makes maintenance harder. E.g. the 'About us' information is now both on the About us page and in the Handbook. He suggests removing the 'About Us' content from the Handbook, and replace it with a link to the 'About us' page.
* The handbook contains much valuable information for contributors but is not that interesting for most wiki visitors who just visit the wiki for longevity related information. He suggests to show only some high level 'how to contribute' information on the 'How to contribute' page so we don't overwhelm visitors (basically just asking people to contact us if they want to help) and then add a prominent link to the Handbook for if they want to dive into all the details.<br />

Andreas Melhede:

* Discussed Discord Role Management on Discord with Stuart McWhinney.
** It is very close to finished and ready to be implemented on our server.

''Max Schulz:''

* Trello Board Set-up & Organization (Tasks on Wiki I would consider once further in development)
** Let's focus only on trello boards that are used, and archive others - I propose:
*** Archiving ''Engineering'' and ''UX'' -> Moving to Jira
*** Merging ''Marketing'' & ''Operations Infrastructure'' into Organisational '''(Please move the tasks you find relevant and archive these)'''
*** Using ''Organisational'' board to manage weekly core meetings
*** Using ''Content creators'' board to manage (to be scheduled) bi-weekly content creators meeting
*** Overall: Can we have one trello group/team with several boards instead of inviting separately for each board? (Should be possible with members instead of guests? [[https://trello.com/en/pricing Pricing Info] | [https://help.trello.com/article/1236-board-guests Board Guests Info]])
** ''Organisational'' board (people need to be added):
*** Should be reviewed and kept up to date weekly
*** Action items should be created as tasks, if applicable - I tried to add most of them, sometimes people have to be assigned again
*** I propose even if task is technical (e.g. making handbook more prominent [https://trello.com/c/fOFtXUmy Trello card]) but relevant to the organisational meetings, it should also be tracked on Trello
*** Proposed board usage:
**** Future ideas for clearly far in the future (months)
**** Backlog for tasks to do soon (weeks)
**** Todo for tasks agreed to be done next, or you want to work on next
**** Once task is worked on -> Move to In Progress
**** If you want someone to review -> Move to In Review
**** If task is done -> Move to Done, can then be shared in the next weekly meeting and archived
** Task hygiene we should agree on ([https://mnschulz.medium.com/managing-work-in-a-startup-e80a3d122620 Personal article]), examples:
*** Meaningful task definitions
*** Assigned doesn't necessarily mean the person does all the work, but takes (especially on the communication side) responsibility
** Side-remark: Tipp to see your cards - [https://help.trello.com/article/819-viewing-all-of-your-cards Trello Help]
* Content writer management:
** Low-hanging fruit for article organisation: Instead of just alphabetic ordering in [[Articles]], can we have groups of articles with the first "Category" as the ordering? (Or another mechanism in Mediawiki?) I think it would be important to separate "Pillar Articles", "General Articles" and "Glossary" already for the management of the articles
** Temporary content writer sheet: [https://docs.google.com/spreadsheets/d/1e9djbjXdMV7m4655yjIISHRoUpB_1mbJcv0O8Zwj1fg/edit#gid=0 link] - will be superseeded by volunteer survey responses (see below)
** Wrote update to content writers [https://docs.google.com/document/d/1FlD9sTf5fPGhBiWYHV9nhzr0ucO6n4CFfEzcdbtnfC0/edit (text link)] with doodle survey for first bi-weekly content meeting after summer (note: should have set a deadlien for doodle ...^^)
**''Content creators'' board:
*** Pillar article label added (also to introductory article, which can be vital as well)
***'''Process for bi-weekly meeting has to be figured out (round-table style?)'''
* Jack created the volunteer survey, ([https://docs.google.com/forms/d/1An8sOTXi_Hne3Elmp1sY1n-3fr6PXwf-bUgPBi8X6e0/edit edit link]) - [https://forms.gle/KHmveeaRSgamtr1D7 shareable link] | answers are linked to the [https://docs.google.com/spreadsheets/d/1FDFYQhQVBdDdHEiGqY1pif0T7sd-suRwOK-0wl7AIXU Google Sheet]
** Should be filled out by all team members so we have an overview.

== 25/08/2021 ==

=== 🧍 Attending ===

* Jack Harley
* Bogdan Dziewierz
* Marc Smeehuijzen
* Ben Wu
* Andreas Melhede
* Heye Groß
* Max Schons
* Stuart

=== 📣 Updates ===
* Considering scoring of new participants to determine level of understanding, also as filtering for determining what level they might contribute at
* Thinking about providing a list of articles/content etc for Wiki contributors to obtain a better overview of the field
* Database of interests of participants, time zones etc.
* Max Schons working on risk factors, subjective vs objective measures of health, various major disease
* Considering submitting core articles to professional proofreading agencies, or reaching out to undergrad/postgrad students
* Heye planning on engaging with EA community at conferences and talking about the Wiki
* Technical meeting bimonthly with Bogdan, Mac, Stuart
* Considering merging Max's medium article with Ben's intro article

{| class="wikitable"
|
=== ✅ Action Items ===

* Continue working on core articles
*
|}

== 18/08/2021 ==

=== 🧍 Attending ===
* Jack Harley
* Bogdan Dziewierz
* Max Schulz
* Andreas Melhede
* Sam Voigt
* Marc Smeehujizen
* Heye Groß

=== 📣 Updates Roundtable ===
Jack Harley

* India times article is being finalised, to be released next week or week after. New co-author [https://medicine.nus.edu.sg/bch/faculty/brian-kennedy/ Brian Kennedy] joined

* More contributors interested to join the project. There is a need for people to help with on-boarding new contributors

* Gave a talk in EA group in Melbourne. This was followed up with an invitation to the medical conference in Melbourne.

* Handbook work is progressing'''.''' We need to make it more prominent and visible in the menu.

''Bogdan Dziewierz''

* Custom namespace "Handbook" created on the Wiki
* Engineering iteration meeting needs to be scheduled. Created new #engineering channel in Discord to help with coordination of such activities.
* Slowly progressing on Life Extension tool

''Heye Groß''

* Will get more involved in Longevity Wiki over next weeks. More clear on working hours.
* Discussed whether Longevity is a topic that is / should be on the agenda for EA compared to other existential risks and how EA can be used as spread-the-word or funding platform for Longevity effectively.
* Open Philantropy: Donates to the most effective areas but have a pessimistic view of longevity research. We think their evaluation is limited because they haven’t done cost / benefits calculation of investing into geroscience. Can be low-hanging fruit for donations, provided cost / benefit calculation is done for them.

''Jack Harley''

* Let’s try to organise symposium or conference once we get funding. EA could be convinced to fund this initiative.

''Max Schulz''

* Meeting Organization in general: I also like the process of always having a pre-created meeting topics from participants file for the next meeting
** Every participant plan can add his points already (I personally like to do this), then the meeting owner already has an idea in advance what people want to talk about and how to potentially structure it (Jack Harley in this case?)
* Updated the about page with pillar articles and ongoing projects suggestion ([[Handbook:Handbook]]). Some open points on my side (see page)
** 5 or 20 pillar articles to start with? Saw conflicting information
** Content should be merged with: [[About]], [[How to contribute]] (Especially "Other Roles")
** In the visual editor, there are quite some "paragraphs" that I can't delete, they don't show up in the source editor ...?
** Open calendar links for meetings would be good (also are there other meetings to know of...?)
* How do you currently navigate the articles on the wiki? For example, how do you find the handbook article? (Any ongoing efforts on the navigation side?)
* There are article drafts shared on Discord with Google Docs, we should encourage everybody to directly write to the Wiki so this work doesn't get lost (e.g. [https://docs.google.com/document/d/1gSJjEJbP_A1Qs_uewoWjkSFUhsyfN1IUNUYIVuxDb7E/edit link]) (The "core articles" that we want to work on should just be categorized accordingly IMHO)
** Similarly, with the glossary suggestion - better if it would be already added to the wiki instead: [https://docs.google.com/document/d/1q2dlsLK76bAXyU3ZPZ_eWn_oI3UFQEtie_8D2nRH5cQ/edit#heading=h.lhdrp4ijtcd2 google docs]
* What is the status of the vision and action plan? ([https://docs.google.com/presentation/d/1rlPZyncQGRW6koCunM23msQyVWEQ0CVyGMnMAUSaE8U/edit#slide=id.g655cbd83be_0_18 Google Slides])
* Idea to try get some funding from the upcoming Gitcoin round from VitaDAO? I know that the high quality articles would make the case stronger, on the other hand they explicitly want to also go for early projects and "open science": [https://docs.google.com/document/d/13rjnkgxCdQ63V1M69cE-moeY6ktRfo5XIF8E9nwaeIU/edit Quadratic Funding Round Document]
* Last week, the process of registering a non-profit was quickly discussed but it's not in the minutes (I don't remember what was discussed)

''Heye Groß / Jack Harley / Bogdan Dziewierz''

* There is need to think about what we need money for so that we can start participating in funding rounds / grants / etc.

''Andres Melhede''

* Waiting for India article so that it can be used as a source for more content to be used on Social Media

{| class="wikitable"
|
=== ✅ Action Items ===

* Jack: There is a need for volunteers to help with on-boarding new contributors

* Bogdan: We need to make it more prominent and visible in the menu
* Bogdan: How to contribute menu item needs to be replaced with Handbook
* Jack: We need to brainstorm and document what we need the funds for so that we can start participating in funding rounds / grants / etc.
* Jack: Let’s try to organise symposium or conference once we get funding.
* Max: Max to follow up with VitaDAO to find out if we can participate in their Gitcoin round.
|}

== 11/08/2021 ==

=== Purpose ===
Regular weekly meeting

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Bogdan Dziewierz, Co-founder & Head of Engineering
* Max Schons, Content Writer
* Max Schulz, Engineering Team Member and Organisational Consultant
* Ben Wu, Head of Content
* Andreas Melhede, Head of Marketing
* Sharon Wong, Content Translator

=== 📣 Updates Roundtable ===

# Name: Max Schulz
## Discussed benefits of the ‘handbook-first’ approach, such as convenience in onboarding new volunteers to the organisation, and having a centralized knowledge base for strategy and roadmap documents. Brought up the need for a central landing page upon which organisational links are easily accessible.
## Discussed platforms for hosting the Handbook, such as Confluence.
# Name Bogdan
## Suggested using the Wiki itself as the ‘Handbook’, and Confluence for the engineering activities. The rest of the team agreed. Offered to create a namespace using MediaWiki for the handbook and landing page.
## Life extension tool is a work in progress.
# Name Jack
## Discussed the role of content writer manager, and suggested Max Schulz be introduced to this role.
## Once content writers are on board with the new content writing strategy, those with a biology background can be tasked with adding data to the life extension tool.
# ‍Name Max Schons
## Outlined briefly the content strategy of creating a few high quality articles then seeking the endorsement of experts in the field, to attract more high quality contributors.
## Provided example of meeting minutes layouts in a handbook: <nowiki>https://github.com/mermaid-js/mermaid/releases</nowiki>
# Name Ben
## Provided update on the Times of India article, which will be published in the coming 1-2 weeks. The article will mention Longevity Wiki in the authors’ biographies section.
# Name Sharon
## Offered to review meeting minutes, and provided suggestions for the minutes - including key references and links at the beginning of the minutes.
# Name Andreas
## Provided updates on social media accounts.
## Did several edits and suggestions for the Aging Article for the Indian News Site.

{| class="wikitable"
|
=== ✅ Action Items ===

* Bogdan to create namespace for Handbook, and Handbook landing page
* Jack follow up on Max’s organizational wiki suggestions
* Jack to follow up with Max Schulz regarding content writers management
* Jack to assign organizational document writing to other members
* Bogdan to organize an Engineering team spring meeting
* Jack to create and share a document of organizational processes
* Max Schulz to forward exemplary handbook to Jack
* Max Schons to continue working on Biomarkers of Healthspan article
* Ben Wu to continue working on Aging Epigenetics article
|}

== 04/08/2021 ==

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Bogdan Dziewierz, Co-founder & Head of Engineering
* Marc Smeehuijzen, Head of UX
* Ben Wu, Head of Content
* Andreas Melhede, Head of Marketing

=== 📣 Updates Roundtable ===

# Name: Bogdan
## Had the kick-off engineering meeting 30 July 2021 with Sam Voigt, Maximilian Schulz and Mark Whitlock. He setup Jira and Confluence. (These are popular project management tools in IT development). The engineering cards on Trello will be moved to Jira. For more details on this meeting, see the minutes on Confluence. (If you don’t have access to Confluence, ask Bogdan).
## Suggestion: split weekly meetings per department (so engineering, marketing, content, etc. all have their own weekly meeting instead of everybody in the same meeting).
## Suggestion: we could move the draft articles that we’re working on from Google Docs to the wiki itself. This way visitors can see the wiki is alive and check recent changes of the articles.
## Continue working on the Life Extension Tool and a glossary extension for the wiki, among other things. We might develop other tools in the future. Jack for instance suggested an interactive roadmap for longevity laboratories in the world.
# Name Ben
## There is a little delay in writing the India Times article on longevity. But it’s 90% done. He will see if we can get a famous professor as co author (e.g. David Sinclair). On Google Docs there’s a draft of the article and members of the team are welcome to provide feedback
# Name Jack
## Talked to Maximillian Schulz who made a number of interesting organizational suggestions for the wiki (see Jack’s email from 4 Aug. 2021). There is a need for organizational docs to be made transparently accessible on the Wiki, and we proposed this be in the form of pages on the Wiki categorized accordingly.
## New marketing expert is interested in joining the project, could work alongside Andreas
## Plan to reach out to expert in Rapamycin (Mikhail Blagosklonny) to seek a review/endorsement for this article on the Wiki.
## Looking for someone who can manage the content writers.
# ‍Name Marc
## Updated the design for the Life Extension Tool. There are now two modes: 1. you can see per species what % life extension has been achieved per intervention and 2. you can see per intervention what % life extension has been achieved per species. The designs can be found on Zeplin. (If you don’t have access to Zeplin, please send Marc your email address so he can add you). He also posted some screenshots of the designs in the UX channel on our Discord server.
## Made English to Dutch translations of the interface elements of the wiki (document is on Google Drive).
# Name Andreas
## Made some social media posts on the 5 key articles that we’re working on.
## Engagement and sharing relevant content on the various social media platforms (especially focused on Twitter)

{| class="wikitable"
|
=== ✅ Action Items ===

* Ben looks for famous professor as co author for India Times article
* Jack follow up on Maximillian’s organizational wiki suggestions
* Jack looks for someone to manage the content writers
* Jack to assign organizational document writing to other members
* Marc joins the engineering team and moves his Trello cards to Jira
|}

== 29/07/2021 ==

=== 🧍 Attending ===

* Jack Harley, Co-Founder
* Andreas Melhede, Head of Marketing
* Ben Wu, Head of Content

=== 🙌 Celebrate wins ===

* New software developer, Mark Whitlock, will join the IT team to help develop the technical side
* Database for the Life Extension Tool (the UX design for which can be viewed here) has been created

=== 💬 Discussion Topics ===

* Who are we trying to target with content? Discussed the need for content that appeals to the masses to fill a gap in content in this space. While we hope to create content that scientists will read, and for credibility most will likely stick with reading review articles so we should bear in mind our target audience of non-specialists.

=== 📣 Updates Roundtable ===

# Name: Jack
## A new contributor, Max Schultz, who has written blog posts about knowledge databases has provided a report on the state of the Wiki, offering avenues for expanding the Wiki. The notes for his meeting agenda with me are attached below this document.
## We have created an excel spreadsheet of data for the Life extension tool, and are encouraging contributors to help expand the data.
## Have created a new folder in the Google Drive called ‘Weekly Meetings’ wherein this Meeting Minutes and future minutes can be saved.
## Discussed the need to update content writers with a new approach of creating a glossary for pillar articles.
# Name Ben
## Joao Pedro’s database contains an extensive list of drugs and their life extension effects, which we can draw from for our own tool. <nowiki>https://genomics.senescence.info/drugs/browse.php</nowiki>

<nowiki>https://genomics.senescence.info/drugs/</nowiki>

We should aim to create a more user-friendly, and simplified version for our tool, focusing on ~20 key drugs that are most relevant to today’s life extension protocols.

# We should focus on data from the ITP (NIA’s Intervention Testing Program) as this is a rigorous and reliable test.

# Name Andreas
## Clarifying the target audience as primarily those who are non-specialists
## Clarified the style of social media posts, as evidence-based and reliable, as advised by Ben.

‍
{| class="wikitable"
|
=== ✅ Action Items ===

* Jack meeting with Max Shulz to discuss further collaboration ideas
* Ben to add list of drugs of interest to lifespan extension tool database
* Ben to add relevant sources to the database for content writers - E.g. ITP
* Assign content writers / other team members with science background to assist with completing data for the life extension tool
* Andreas to create Discord channel for meeting minutes
* Communicate to content writers the new deliverables of expanding the glossary associated with the ‘pillar’ articles
|}

Cryonics

2021-09-07T09:49:30Z

BLife: /* The Cost of Cryonics */

Cryonics

2021-09-07T09:44:47Z

BLife:

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>
[[File:Patient long term care bay at Alcor.jpg|thumb|The patient long term care bay at Alcor Life Extension Foundation, circa 2020.]]
Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it is unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==The Cost of Cryonics==

Cryonics is typically paid for using life insurance. As of 2020, the cost of a cryopreservation procedure is $80,000 at [https://alcor.org/ Alcor], or $28,000 at the [https://www.cryonics.org/ Cryonics Institute], or $18,000 at [http://kriorus.ru/en KrioRus]. (These prices are not directly comparable, because the features of the cryonics plans are different at each organization, including the options for "standby and stabilization".) The majority of people do not pay for cryopreservation "out of pocket". They typically pay for cryonics using a life insurance policy, which tends to make cryonics services more affordable. For example, the cost of a suitable term life insurance policy for a healthy middle-aged adult might be a few hundred dollars per year. The full cryopreservation costs are not due until the time of death, which is why cryonics services can generally be paid with a life insurance policy.

It is common for cryonics clients to purchase a term or permanent life policy with a face value of $250,000. (This policy size is also commonly offered by insurance companies.) As of 2019, a policy of this amount is more than sufficient to pay for a standard cryonics plan from any known cryonics organization, with significant funds remaining for other desired beneficiaries.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==Cryonics Organizations==

===Cryonics Storage Organizations===

* [https://www.alcor.org/ Alcor Life Extension Foundation], Cryonics Storage Organization, in Scottsdale AZ, USA.
* [https://www.cryonics.org/ Cryonics Institute], Cryonics Storage Organization, in Clinton Township MI, USA.
* [https://kriorus.ru/en KrioRus], Cryonics Storage Organization, in Moscow, Russia.

===Stabilization and Transport Companies===

* [https://suspendedanimationlabs.com/ Suspended Animation, Inc], Cryonics Stabilization and Transport Company, operating within the continental USA.

===Information and Advocacy===

* [https://www.longecity.org/ LongeCity], Information and Advocacy for Cryonics and Life Extension.

===New Organizations and Projects===

* [https://southerncryonics.com/ Southern Cryonics], A Cryonics Storage Organization constructing a new cryonics storage facility, in New South Wales, Australia. They are projected to open in 2022.

==References==
<references />
[[Category:Longevity]]

Cryonics

2021-09-07T09:43:44Z

BLife: Added a photo of the Alcor Patient Long Term Care Bay.

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>
[[File:Patient long term care bay at Alcor.jpg|thumb|The patient long term care bay at Alcor Life Extension Foundation, circa 2020.]]
Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==The Cost of Cryonics==

Cryonics is typically paid for using life insurance. As of 2020, the cost of a cryopreservation procedure is $80,000 at [https://alcor.org/ Alcor], or $28,000 at the [https://www.cryonics.org/ Cryonics Institute], or $18,000 at [http://kriorus.ru/en KrioRus]. (These prices are not directly comparable, because the features of the cryonics plans are different at each organization, including the options for "standby and stabilization".) The majority of people do not pay for cryopreservation "out of pocket". They typically pay for cryonics using a life insurance policy, which tends to make cryonics services more affordable. For example, the cost of a suitable term life insurance policy for a healthy middle-aged adult might be a few hundred dollars per year. The full cryopreservation costs are not due until the time of death, which is why cryonics services can generally be paid with a life insurance policy.

It is common for cryonics clients to purchase a term or permanent life policy with a face value of $250,000. (This policy size is also commonly offered by insurance companies.) As of 2019, a policy of this amount is more than sufficient to pay for a standard cryonics plan from any known cryonics organization, with significant funds remaining for other desired beneficiaries.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==Cryonics Organizations==

===Cryonics Storage Organizations===

* [https://www.alcor.org/ Alcor Life Extension Foundation], Cryonics Storage Organization, in Scottsdale AZ, USA.
* [https://www.cryonics.org/ Cryonics Institute], Cryonics Storage Organization, in Clinton Township MI, USA.
* [https://kriorus.ru/en KrioRus], Cryonics Storage Organization, in Moscow, Russia.

===Stabilization and Transport Companies===

* [https://suspendedanimationlabs.com/ Suspended Animation, Inc], Cryonics Stabilization and Transport Company, operating within the continental USA.

===Information and Advocacy===

* [https://www.longecity.org/ LongeCity], Information and Advocacy for Cryonics and Life Extension.

===New Organizations and Projects===

* [https://southerncryonics.com/ Southern Cryonics], A Cryonics Storage Organization constructing a new cryonics storage facility, in New South Wales, Australia. They are projected to open in 2022.

==References==
<references />
[[Category:Longevity]]

File:Patient long term care bay at Alcor.jpg

2021-09-07T09:40:47Z

BLife:

The patient long term care bay at Alcor Life Extension Foundation. (Photo license, CC BY-NC 2.0.)

Cryonics

2021-09-07T09:25:18Z

BLife:

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==The Cost of Cryonics==

Cryonics is typically paid for using life insurance. As of 2020, the cost of a cryopreservation procedure is $80,000 at [https://alcor.org/ Alcor], or $28,000 at the [https://www.cryonics.org/ Cryonics Institute], or $18,000 at [http://kriorus.ru/en KrioRus]. (These prices are not directly comparable, because the features of the cryonics plans are different at each organization, including the options for "standby and stabilization".) The majority of people do not pay for cryopreservation "out of pocket". They typically pay for cryonics using a life insurance policy, which tends to make cryonics services more affordable. For example, the cost of a suitable term life insurance policy for a healthy middle-aged adult might be a few hundred dollars per year. The full cryopreservation costs are not due until the time of death, which is why cryonics services can generally be paid with a life insurance policy.

It is common for cryonics clients to purchase a term or permanent life policy with a face value of $250,000. (This policy size is also commonly offered by insurance companies.) As of 2019, a policy of this amount is more than sufficient to pay for a standard cryonics plan from any known cryonics organization, with significant funds remaining for other desired beneficiaries.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==Cryonics Organizations==

===Cryonics Storage Organizations===

* [https://www.alcor.org/ Alcor Life Extension Foundation], Cryonics Storage Organization, in Scottsdale AZ, USA.
* [https://www.cryonics.org/ Cryonics Institute], Cryonics Storage Organization, in Clinton Township MI, USA.
* [https://kriorus.ru/en KrioRus], Cryonics Storage Organization, in Moscow, Russia.

===Stabilization and Transport Companies===

* [https://suspendedanimationlabs.com/ Suspended Animation, Inc], Cryonics Stabilization and Transport Company, operating within the continental USA.

===Information and Advocacy===

* [https://www.longecity.org/ LongeCity], Information and Advocacy for Cryonics and Life Extension.

===New Organizations and Projects===

* [https://southerncryonics.com/ Southern Cryonics], A Cryonics Storage Organization constructing a new cryonics storage facility, in New South Wales, Australia. They are projected to open in 2022.

==References==
<references />
[[Category:Longevity]]

Cryonics

2021-09-07T09:15:52Z

BLife: Added category, Longevity

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==The Cost of Cryonics==

Cryonics is typically paid for using life insurance. As of 2020, the cost of a cryopreservation procedure is $80,000 at [https://alcor.org/ Alcor], or $28,000 at the [https://www.cryonics.org/ Cryonics Institute], or $18,000 at [http://kriorus.ru/en KrioRus]. (These prices are not directly comparable, because the features of the cryonics plans are different at each organization, including the options for "standby and stabilization".) The majority of people do not pay for cryopreservation "out of pocket". They typically pay for cryonics using a life insurance policy, which tends to make cryonics services more affordable. For example, the cost of a suitable term life insurance policy for a healthy middle-aged adult might be a few hundred dollars per year. The full cryopreservation costs are not due until the time of death, which is why cryonics services can generally be paid with a life insurance policy.

It is common for cryonics clients to purchase a term or permanent life policy with a face value of $250,000. (This policy size is also commonly offered by insurance companies.) As of 2019, a policy of this amount is more than sufficient to pay for a standard cryonics plan from any known cryonics organization, with significant funds remaining for other desired beneficiaries.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==Cryonics Organizations==

===Cryonics Storage Organizations===

* [https://www.alcor.org/ Alcor Life Extension Foundation], Cryonics Storage Organization, in Scottsdale AZ, USA.
* [https://www.cryonics.org/ Cryonics Institute], Cryonics Storage Organization, in Clinton Township MI, USA.
* [https://kriorus.ru/en KrioRus], Cryonics Storage Organization, in Moscow, Russia.

===Stabilization and Transport Companies===

* [https://suspendedanimationlabs.com/ Suspended Animation, Inc], Cryonics Stabilization and Transport Company, operating within the continental USA.

===Information and Advocacy===

* [https://www.longecity.org/ LongeCity], Information and Advocacy for Cryonics and Life Extension.

===New Organizations and Projects===

* [https://southerncryonics.com/ Southern Cryonics], A Cryonics Storage Organization constructing a new cryonics storage facility, in New South Wales, Australia. They have projected to open near the end of the year 2021.

==References==
<references />
[[Category:Longevity]]

Cryonics

2021-09-07T09:11:45Z

BLife: Reordered sections

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==The Cost of Cryonics==

Cryonics is typically paid for using life insurance. As of 2020, the cost of a cryopreservation procedure is $80,000 at [https://alcor.org/ Alcor], or $28,000 at the [https://www.cryonics.org/ Cryonics Institute], or $18,000 at [http://kriorus.ru/en KrioRus]. (These prices are not directly comparable, because the features of the cryonics plans are different at each organization, including the options for "standby and stabilization".) The majority of people do not pay for cryopreservation "out of pocket". They typically pay for cryonics using a life insurance policy, which tends to make cryonics services more affordable. For example, the cost of a suitable term life insurance policy for a healthy middle-aged adult might be a few hundred dollars per year. The full cryopreservation costs are not due until the time of death, which is why cryonics services can generally be paid with a life insurance policy.

It is common for cryonics clients to purchase a term or permanent life policy with a face value of $250,000. (This policy size is also commonly offered by insurance companies.) As of 2019, a policy of this amount is more than sufficient to pay for a standard cryonics plan from any known cryonics organization, with significant funds remaining for other desired beneficiaries.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==Cryonics Organizations==

===Cryonics Storage Organizations===

* [https://www.alcor.org/ Alcor Life Extension Foundation], Cryonics Storage Organization, in Scottsdale AZ, USA.
* [https://www.cryonics.org/ Cryonics Institute], Cryonics Storage Organization, in Clinton Township MI, USA.
* [https://kriorus.ru/en KrioRus], Cryonics Storage Organization, in Moscow, Russia.

===Stabilization and Transport Companies===

* [https://suspendedanimationlabs.com/ Suspended Animation, Inc], Cryonics Stabilization and Transport Company, operating within the continental USA.

===Information and Advocacy===

* [https://www.longecity.org/ LongeCity], Information and Advocacy for Cryonics and Life Extension.

===New Organizations and Projects===

* [https://southerncryonics.com/ Southern Cryonics], A Cryonics Storage Organization constructing a new cryonics storage facility, in New South Wales, Australia. They have projected to open near the end of the year 2021.

==References==
<references />

Cryonics

2021-09-07T09:10:19Z

BLife: Added section, Cryonics Organizations

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==The Cost of Cryonics==

Cryonics is typically paid for using life insurance. As of 2020, the cost of a cryopreservation procedure is $80,000 at [https://alcor.org/ Alcor], or $28,000 at the [https://www.cryonics.org/ Cryonics Institute], or $18,000 at [http://kriorus.ru/en KrioRus]. (These prices are not directly comparable, because the features of the cryonics plans are different at each organization, including options for "standby and stabilization".) The majority of people do not pay for cryopreservation "out of pocket". They typically pay for cryonics using a life insurance policy, which tends to make cryonics services more affordable. For example, the cost of a suitable term life insurance policy for a healthy middle-aged adult might be a few hundred dollars per year. The full cryopreservation costs are not due until the time of death, which is why cryonics services can generally be paid with a life insurance policy.

It is common for cryonics clients to purchase a term or permanent life policy with a face value of $250,000. (This policy size is also commonly offered by insurance companies.) As of 2019, a policy of this amount is more than sufficient to pay for a standard cryonics plan from any known cryonics organization, with significant funds remaining for other desired beneficiaries.

==Cryonics Organizations==

===Cryonics Storage Organizations===

* [https://www.alcor.org/ Alcor Life Extension Foundation], Cryonics Storage Organization, in Scottsdale AZ, USA.
* [https://www.cryonics.org/ Cryonics Institute], Cryonics Storage Organization, in Clinton Township MI, USA.
* [https://kriorus.ru/en KrioRus], Cryonics Storage Organization, in Moscow, Russia.

===Stabilization and Transport Companies===

* [https://suspendedanimationlabs.com/ Suspended Animation, Inc], Cryonics Stabilization and Transport Company, operating within the continental USA.

===Information and Advocacy===

* [https://www.longecity.org/ LongeCity], Information and Advocacy for Cryonics and Life Extension.

===New Organizations and Projects===

* [https://southerncryonics.com/ Southern Cryonics], A Cryonics Storage Organization constructing a new cryonics storage facility, in New South Wales, Australia. They have projected to open near the end of the year 2021.

==References==
<references />

Cryonics

2021-09-07T08:58:05Z

BLife: Added section, Cost of Cryonics

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==Cost of Cryonics==

Cryonics is typically paid for using life insurance. As of 2020, the cost of a cryopreservation procedure is $80,000 at [https://alcor.org/ Alcor], or $28,000 at the [https://www.cryonics.org/ Cryonics Institute], or $18,000 at [http://kriorus.ru/en KrioRus]. (These prices are not directly comparable, because the features of the cryonics plans are different at each organization, including options for "standby and stabilization".) The majority of people do not pay for cryopreservation "out of pocket". They typically pay for cryonics using a life insurance policy, which tends to make cryonics services more affordable. For example, the cost of a suitable term life insurance policy for a healthy middle-aged adult might be a few hundred dollars per year. The full cryopreservation costs are not due until the time of death, which is why cryonics services can generally be paid with a life insurance policy.

It is common for cryonics clients to purchase a term or permanent life policy with a face value of $250,000. (This policy size is also commonly offered by insurance companies.) As of 2019, a policy of this amount is more than sufficient to pay for a standard cryonics plan from any known cryonics organization, with significant funds remaining for other desired beneficiaries.
==References==
<references />

Cryonics

2021-09-07T08:30:29Z

BLife: /* Standard Cryopreservation Procedures */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Information theoretic death

2021-09-07T05:20:50Z

BLife:

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:
A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.
The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

Information-theoretic death arises in the context of [[cryonics]], which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. If currently preserved cryonics patients are not dead by information theoretic criteria, then it may be possible to revive those patients in the future using sufficiently advanced medical technology. If the information encoded in the brain of a particular cryonics patient has been completely destroyed, then revival of that patient may not ever become feasible. Because of this, the use of information-theoretic criteria has formed the basis of an ethical argument that states that cryonics is an attempt to save lives, rather than being an interment method for the dead.

==External Links==

*Molecular Repair of the Brain. (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
*Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
*Ethics review: Dark angels - the problem of death in intensive care. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
*Albert Einstein’s brain and information-theoretic death. (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

==Credits==
Portions of this article were originally copied from content on Information Theoretic Death at Wikipedia.org (2010), and En-Academic.com (2021), using a compatible Creative Commons License.

==References==
<references />
[[Category:Glossary]]

Information theoretic death

2021-09-07T04:47:25Z

BLife:

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:
A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.
The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

Information-theoretic death arises in the context of [[cryonics]], which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. If currently preserved cryonics patients are not dead by information theoretic criteria, then it may be possible to revive those patients in the future using sufficiently advanced medical technology. If the information encoded in the brain of a particular cryonics patient has been completely destroyed, then revival of that patient may not ever become feasible. Because of this, the use of information-theoretic criteria has formed the basis of an ethical argument that states that cryonics is an attempt to save lives, rather than being an interment method for the dead.

==External Links==

*Molecular Repair of the Brain. (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
*Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
*Ethics review: Dark angels - the problem of death in intensive care. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
*Albert Einstein’s brain and information-theoretic death. (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

==Credits==
Portions of this article were originally copied from content on Information Theoretic Death at Wikipedia.org (2010), and En-Academic.com (2021), using a Creative Commons License.

==References==
<references />
[[Category:Glossary]]

Information theoretic death

2021-09-07T04:43:20Z

BLife: /* Credits */

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:
A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.
The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

Information-theoretic death arises in the context of [[cryonics]], which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. If currently preserved cryonics patients are not dead by information theoretic criteria, then it may be possible to revive those patients by using a sufficiently advanced future medical technology. If the information encoded in the brain of a particular cryonics patient has been completely destroyed, then revival of that patient may not ever become feasible. Because of this, the use of information-theoretic criteria has formed the basis of an ethical argument that states that cryonics is an attempt to save lives, rather than being an interment method for the dead.

==External Links==

*Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
*Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
*Ethics review: Dark angels-- the problem of death in intensive care (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
*Albert Einstein’s brain and information-theoretic death (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

==Credits==
Parts of this article were originally copied from articles on Information Theoretic Death at Wikipedia.org (2010), and En-Academic.com (2021), using a Creative Commons License.

==References==
<references />
[[Category:Glossary]]

Information theoretic death

2021-09-07T04:42:20Z

BLife: Added improvements and attributions

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:
A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.
The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

Information-theoretic death arises in the context of [[cryonics]], which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. If currently preserved cryonics patients are not dead by information theoretic criteria, then it may be possible to revive those patients by using a sufficiently advanced future medical technology. If the information encoded in the brain of a particular cryonics patient has been completely destroyed, then revival of that patient may not ever become feasible. Because of this, the use of information-theoretic criteria has formed the basis of an ethical argument that states that cryonics is an attempt to save lives, rather than being an interment method for the dead.

==External Links==

*Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
*Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
*Ethics review: Dark angels-- the problem of death in intensive care (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
*Albert Einstein’s brain and information-theoretic death (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

==Credits==
Parts of this article were copied from articles on Information Theoretic Death at Wikipedia.org (2010), and En-Academic.com (2021), using a Creative Commons License.

==References==
<references />
[[Category:Glossary]]

Information theoretic death

2021-09-07T04:21:22Z

BLife:

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:

A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.

The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

Information-theoretic death arises in the context of [[cryonics]], which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. If currently preserved cryonics patients are not dead by information theoretic criteria, then it may be possible to revive those patients by using a sufficiently advanced future medical technology. If the information encoded in the brain of a particular cryonics patient has been completely destroyed, then revival of that patient may not ever become feasible. Because of this, the use of information-theoretic criteria has formed the basis of an ethical argument that states that cryonics is an attempt to save lives, rather than being an interment method for the dead.

== External Links ==

* Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
* Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
* Ethics review: Dark angels-- the problem of death in intensive care (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
* Albert Einstein’s brain and information-theoretic death (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

== References ==
<references />
[[Category:Glossary]]

Information theoretic death

2021-09-07T04:16:23Z

BLife:

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:

A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.

The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

Information-theoretic death arises in the context of cryonics, which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. If the currently preserved cryonics patients are not dead by information theoretic criteria, then it may be possible to revive those patients by using a sufficiently advanced future medical technology. If the information encoded in the brain of a specific cryonics patient has been destroyed, then revival of that cryonics patient may not ever be feasible. Because of this, the use of information-theoretic criteria has formed the basis of ethical arguments that state that cryonics is an attempt to save lives rather than being an interment method for the dead.

== External Links ==

* Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
* Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
* Ethics review: Dark angels-- the problem of death in intensive care (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
* Albert Einstein’s brain and information-theoretic death (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

== References ==
<references />
[[Category:Glossary]]

Information theoretic death

2021-09-07T04:13:27Z

BLife:

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:

A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.

The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

Information-theoretic death arises in the context of cryonics, which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. If current cryopreserved patients are not dead by information theoretic criteria, then it may be possible to revive those patients by using a sufficiently advanced future medical technology. If the information encoded in the brains of cryonics patients has been destroyed, then revival of cryonics patients may not be feasible. Therefore, the use of information-theoretic criteria has formed the basis of ethical arguments that state that cryonics is an attempt to save lives rather than being an interment method for the dead.

== External Links ==

* Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
* Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
* Ethics review: Dark angels-- the problem of death in intensive care (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
* Albert Einstein’s brain and information-theoretic death (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

== References ==
<references />
[[Category:Glossary]]

Cryonics

2021-09-07T01:34:15Z

BLife: Reordered sections

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T01:31:51Z

BLife: /* Conceptual Foundation */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T01:31:01Z

BLife: /* Conceptual Foundation */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T01:30:12Z

BLife: /* Concepts Affecting the Feasibility Of Cryonics */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T01:04:27Z

BLife: /* Standard Cryopreservation Procedures */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the cold ischemia associated with the transport phase can be minimized or eliminated. This can be accomplished if, 1) The person relocates to the same city as their cryonics facility at some point before death occurs, or 2) A field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T01:01:07Z

BLife: /* Cryopreservation Procedures */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Standard Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T01:00:09Z

BLife: /* Cryopreservation Procedures */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Applied Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T00:58:11Z

BLife: /* Cryopreservation Procedures */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T00:57:23Z

BLife: /* Cryopreservation Procedures */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Human Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T00:50:36Z

BLife: Added section, History (citations pending)

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==History==

===1931 - 1962 ===

'''Research in cryobiology begins, and the idea of cryonics is conceived.'''

* 1931: Robert Ettinger (the "Father of Cryonics") conceived the cryonics idea after reading a story called The Jameson Satellite.
* 1947: While in the hospital for battle wounds, Robert Ettinger discovered that research in cryogenics was being done by French biologist Jean Rostand.
* 1949: Bull semen was cryopreserved for the first time.
* 1962: Robert Ettinger published his cryonics idea in a nonfiction book called "The Prospect of Immortality".

===1963 - 1974===

'''Early cryonics organizations are formed, but they struggle to maintain their patients in liquid nitrogen. Only 3 out of the 22 people cryopreserved during this period remain preserved to this day.'''

* 1963: Evan Cooper founded the world's first cryonics organization, the Life Extension Society, which was intended to promote the idea of cryonics.
* 1965: A New York industrial designer named Karl Werner coined the word "cryonics".
* 1965: Early cryonics storage organizations were created. These included the Cryonics Society of California and the Cryonics Society of New York."
* 1967: Dr. James H. Bedford became the first man to enter cryonic suspension. Bedford remains frozen to this day at Alcor.
* 1968: A TV repairman, Robert Nelson, oversaw the worst historic cryonics disaster (the "Chatsworth Disaster"). Nine people were frozen, and later thawed.

===1975 - 1999===

'''The first professional cryonics storage organizations are created, and slowly grow during these years. Financial and procedural policies are developed which enable long term, stable patient storage.'''

* 1976: Alcor carries out the first human cryopreservation where cardiopulmonary support is initiated immediately after clinical death is pronounced.
* 1979: The first cryopreservation of a companion animal was performed, which was Mike Darwin’s childhood dog “Mitzi”.
* 1980: Leaf et al., carried out the first closed circuit perfusions with controlled and monitored increases in cryoprotectant concentration.
* 1981: The first paper suggesting that nanotechnology could reverse freezing injury is published.
* 1984: The first paper showing that large organs can be cryopreserved without structural damage from ice is published.
* 1995: Darwin et al., document the first use of a premedication protocol to mitigate ischemia injury in a cryonics patient.
* 1995: Alcor begins using a concentrated glycerol solution as their cryoprotective strategy.
* 1997: Alcor forms the Patient Care Trust as an entirely separate entity to manage and protect the funding for cryonics patients.

===2000 - 2009===

'''Cryonics organizations begin to use vitrification solution to preserve their patients. Stabilization and Transport organizations are formed.'''

* 2000: The application of vitrification to a relatively large tissue of medical interest, vascular grafts, is successful for the first time.
* 2002: Suspended Animation, Inc was created to provide advanced Stabilization and Transport services to other cryonics organizations.
* 2002: Alcor cryopreserved baseball star Ted Williams. Two of his children stated that Williams wanted to be cryopreserved, but a third child objected.
* 2003: Carnegie Mellon University receives a $1.3 million grant from the U.S. government to study vitrification of tissue for medical applications.
* 2004: The Cryonics Institute uses a cryoprotectant, CI-VM-1, for the first time.
* 2006: KrioRus was created in Moscow, Russia. This was the first cryonics storage organization located outside the United States.

===2010 - 2019===

'''Cryonics organizations grow at a faster rate in comparison to previous years. The concept of cryonics becomes more widely known to the public.'''

* 2011: CI shipped its vitrification solution (CI-VM-1) to the United Kingdom so European cryonics patients can be vitrified before transport to the USA.
* 2011: Robert Ettinger (the "Father of Cryonics") was cryopreserved at the Cryonics Institute, at age 92.
* 2015: The New York Times published "A Dying Young Woman's Hope in Cryonics and a Future" for Kim Suozzi. Public interest in cryonics surged.
* 2017: Southern Cryonics secured approximately $1 MM(AUD) to build the first cryonics facility in Australia, with construction to begin in 2020.
* 2018: Alcor received a five million dollar donation to be used for research which would benefit cryonics technology.

==References==
<references />

Cryonics

2021-09-07T00:36:33Z

BLife: /* The Scientists' Open Letter on Cryonics */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

[https://www.biostasis.com/scientists-open-letter-on-cryonics/ The Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology, Computing, Ethics, and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==References==
<references />

Cryonics

2021-09-07T00:34:14Z

BLife: /* The Scientists' Open Letter on Cryonics */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

The [https://www.biostasis.com/scientists-open-letter-on-cryonics/ Scientists' Open Letter on Cryonics] is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology and Computing, Ethics and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,
([https://www.biostasis.com/scientists-open-letter-on-cryonics/ 68 Signatories])

==References==
<references />

Cryonics

2021-09-07T00:25:39Z

BLife: Added section, Scientists Open Letter on Cryonics

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

== The Scientists' Open Letter on Cryonics ==

The Scientists' Open Letter on Cryonics is a collaborative document in support of cryonics. The signatories are largely PhD holding scientists, researchers, or professors. Together they encompass various fields relevant to cryonics, such as: Biology, Cryobiology, Neuroscience, Physical Science, Nanotechnology and Computing, Ethics and Theology. A quote from this letter is below.

To whom it may concern,

Cryonics is a legitimate science-based endeavor that seeks to preserve human beings, especially the human brain, by the best technology available. Future technologies for resuscitation can be envisioned that involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.

With a view toward these developments, there is a credible possibility that cryonics performed under the best conditions achievable today can preserve sufficient neurological information to permit eventual restoration of a person to full health.

The rights of people who choose cryonics are important, and should be respected.

Sincerely,

(68 Signatories)

==References==
<references />

Cryonics

2021-09-07T00:18:46Z

BLife: /* Cryopreservation Procedures */

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, for long term storage in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==References==
<references />

Cryonics

2021-09-07T00:17:50Z

BLife: Improved Cryopreservation Procedures section

Cryonics is the practice of preserving a human body at ultra-cold temperatures for multiple years, with the intention of restoring good health if that is made possible by future medical technologies.<ref name=":0">"Cryonics Definition." Cambridge English Dictionary, https://dictionary.cambridge.org/us/dictionary/english/cryonics</ref><ref name=":1">"What is Cryonics." Alcor Life Extension Foundation, https://www.alcor.org/what-is-cryonics/</ref><ref name=":2">"Cryonics Frequently Asked Questions (FAQs)." Cryonics Institute, https://www.cryonics.org/about-us/faqs/</ref>

Cryonics is considered an experimental procedure. It is not yet possible to revive an adult human being from cryopreservation, and it's unknown if revival will ever become possible. There has been controversy within the scientific community regarding the technical feasibility of cryonics resuscitation, with support or skepticism from various scientists. If cryonics resuscitation becomes possible in the future, it would likely require advanced technologies such as molecular level repair, and detailed tissue regeneration.<ref name=":3">“Scientists’ Open Letter on Cryonics.” Biostasis.com, https://www.biostasis.com/scientists-open-letter-on-cryonics/</ref>

The first human cryopreservation was performed on Dr. James Bedford in January 1967.<ref>"Evaluation of the Condition of Dr. James H. Bedford After 24 Years of Cryonic Suspension." Alcor, Aug. 1991, https://www.alcor.org/library/bedford-condition/</ref> As of 2020, there are about 390 individuals cryopreserved around the world, and about 3,100 people hold contracts with cryonics service providers to be cryopreserved immediately after their legal death.<ref name=":10">"Cryonics Institute Member Statistics." Cryonics Institute, https://www.cryonics.org/ci-landing/member-statistics/</ref><ref name=":11">"Alcor Membership Statistics." Alcor, https://alcor.org/AboutAlcor/membershipstats.html</ref> Major cryonics storage companies include the Alcor Foundation and the Cryonics Institute in the USA, and KrioRus in Russia. A network of other cryonics organizations provide standby and stabilization services, local emergency response, cryonics information and outreach, and fundamental or applied research. There is some overlap between the goals of the cryonics field, and the wider organ cryopreservation and life extension fields.<ref>Finger, Erik B., and John C. Bischof. "Cryopreservation by Vitrification: a Promising Approach for Transplant Organ Banking." Current Opinion in Organ Transplantation, 2018, doi:10.1097/mot.0000000000000534</ref><ref>Corbyn, Zoë. "Live Forever: Scientists Say They'll Extend Life 'Well beyond 120'." The Guardian, 11 Jan. 2015, https://www.theguardian.com/science/2015/jan/11/-sp-live-forever-extend-life-calico-google-longevity</ref>

== Conceptual Foundation==

===Summary ===

The practice of cryonics is based on a combination of current scientific understandings ([[Cryonics#Concepts Affecting the Feasibility Of Cryonics|knowns]]) and future technological possibilities ([[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|unknowns]]). Some of the [[Cryonics#Concepts Affecting the Feasibility Of Cryonics|concepts affecting the feasibility of cryonics]] are further described in later sections.

People choose to use cryonics services in the hope that their legal death will be temporary instead of permanent.<ref name=":0" /><ref name=":1" /><ref name=":2" /> They would like to be revived at a future date and restored to good health, if that is made possible by future medical technologies. The use of advanced technologies to revive a person from a cryopreserved state may or may not become feasible, for reasons discussed here.

It is known that [[Cryonics#Known: Life can be stopped and restarted using very cold temperatures.2C in some organisms.|life can be stopped and restarted using very cold temperatures in some organisms]].<ref name=":4">“The Impact of Vitrification in Artificial Reproductive Technology Programmes.” European Medical Journal, 17 Sept. 2018, https://www.emjreviews.com/reproductive-health/article/the-impact-of-vitrification-in-artificial-reproductive-technology-programmes/</ref><ref name=":5">Vita-More, Natasha, and Daniel Barranco. "Persistence of Long-Term Memory in Vitrified and Revived Caenorhabditis elegans." Rejuvenation Research (2015): 458-63. doi:10.1089/rej.2014.1636</ref><ref name=":6">Koštál, Vladimír, et al. “Hyperprolinemic Larvae of the Drosophilid Fly,Chymomyza Costata, Survive Cryopreservation in Liquid Nitrogen.” Proceedings of the National Academy of Sciences, 2011, doi:10.1073/pnas.1107060108</ref> it is known that for large organisms, the currently applied cooldown and rewarming processes cause [[Cryonics#Unknown: How much of the human mind is preserved during cryopreservation.3F .28How much damage occurs.3F.29|varying amounts of tissue damage]]. An educated guess can be made about the types of tissue damage that are sustained in any particular human cryopreservation case. The amounts of damage can vary greatly depending on the cryopreservation timelines, and the techniques applied.<ref>Best BP. Vascular and neuronal ischemic damage in cryonics patients. Rejuvenation Res. 2012 Apr;15(2):165-9. doi: 10.1089/rej.2011.1272. PMID: 22533424.</ref> The amounts of neurological damage cannot be quantified in detail using current technology, because our understanding of the neurological basis of the mind is incomplete, and because we do not know the capabilities of future medical repair technologies.<ref name=":7">Lemler, Jerry, et al. “The Arrest of Biological Time as a Bridge to Engineered Negligible Senescence.” Annals of the New York Academy of Sciences, 2004, doi:10.1196/annals.1297.104</ref> Specifically, the mechanisms and systems by which personality and memory are physiologically encoded within the nervous system are not yet fully understood.<ref name=":8">Poo, Mm., Pignatelli, M., Ryan, T.J. ''et al.'' What is memory? The present state of the engram. ''BMC Biol'' 14, 40 (2016). <nowiki>https://doi.org/10.1186/s12915-016-0261-6</nowiki></ref>

In principle, a sufficiently advanced medical technology could repair some or all of the tissue damage caused by current cryopreservation technologies.<ref>Merkle, R.C. “The Technical Feasibility of Cryonics.” Medical Hypotheses, 1992, doi:10.1016/0306-9877(92)90133-w</ref><ref name=":9">Best, Benjamin. “Scientific Justification of Cryonics Practice.” Rejuvenation Research, 2008, doi:10.1089/rej.2008.0661</ref> The detailed repair of an organism or human being at the cellular and molecular scales [[Cryonics#Known: The detailed repair of an organism does not conflict with any known scientific principles.|does not conflict with any known scientific principles]]. However, scientific possibility does not necessarily mean that comprehensive repairs will become feasible. There are significant engineering challenges involved with the development of medical technologies that would be capable of detailed tissue repair throughout a whole organism. Future technologies can currently be envisioned which involve molecular repair by nanomedicine, highly advanced computation, detailed control of cell growth, and tissue regeneration.<ref name=":3" /> The trend for medical technologies to become more advanced over historic time frames increases the optimism that cryonics could work, but the historic trends do not guarantee success.<ref>Hajar, Rachel. “History of Medicine Timeline.” Heart Views, 2015, doi:10.4103/1995-705x.153008</ref><ref>“Timeline of Discovery.” Harvard Medical School, https://hms.harvard.edu/about-hms/history-hms/timeline-discovery</ref>

=== Concepts Affecting the Feasibility Of Cryonics ===

==== Known: Life can be stopped and restarted using very cold temperatures, in some organisms. ====

It's known that life can be stopped and restarted using very low temperatures in some organisms, as long as small scale biological structures are preserved. The cryopreservation and revival of a variety of species of whole small organisms, as well as human embryos, has become routine in science and medicine over recent decades.<ref name=":4" /><ref name=":5" /><ref name=":6" /> The revival of adult human beings is not currently possible, partially due to the size of the tissues involved. It is currently possible to vitrify and revive small organisms with very little damage, but in larger organisms, various types of tissue damage are caused by the perfusion, cooldown, and the rewarming processes.<ref>Taylor, Michael J., et al. “New Approaches to Cryopreservation of Cells, Tissues, and Organs.” Transfusion Medicine and Hemotherapy, 2019, doi:10.1159/000499453</ref>

==== Known: The detailed repair of an organism does not conflict with any known scientific principles. ====

[[Information Theoretic Death|Information theoretic death]] is the disruption of the structures which encode memory and personality within a brain to such an extent that the recovery or repair of the original person becomes theoretically impossible.<ref>Merkle, R C. “Information-Theoretic Death.” Merkle.com, http://www.merkle.com/definitions/infodeath.html</ref> As long as a person has not suffered information theoretic death, there is no known scientific principle that would prevent the use of sufficiently advanced medical technology to repair or rejuvenate the person to an appropriate level of functionality. As of 2020, there are no peer-reviewed scientific papers which claim that cryonics cannot work. However, there are writings in other media which are skeptical about cryonics. In general, the scientifically minded writings against cryonics revival have tended to argue against its feasibility, or sometimes its desirability, but not its scientific possibility.<ref>Crowley, Paul. "A Survey of Anti-Cryonics Writing." LessWrong.com, 7 Feb. 2010, https://www.lesswrong.com/posts/ZXaRHHLsxaTTQQsZb/a-survey-of-anti-cryonics-writing</ref><ref name=":12">Gorski, David. “Cold Reality versus the Wishful Thinking of Cryonics.” sciencebasedmedicine.org, 2 Aug. 2014, https://sciencebasedmedicine.org/cold-reality-versus-the-wishful-thinking-of-cryonics/</ref> Some writings have incorrectly assumed that the purpose of cryonics was to copy the patient's mind into a digital form (also known as mind uploading), instead of the repair and revival of their biological body.<ref>Hendricks, Michael. "The False Science of Cryonics: Brain Uploads" MIT Technology Review, 16 Sept. 2015, https://www.technologyreview.com/s/541311/the-false-science-of-cryonics/</ref>

==== Known: Medical repair technologies have historically tended to become more capable over time. ====

The ability of medical technology to repair human tissue has unambiguously increased and accelerated over historic timescales.<ref>“Looking Back on the Millennium in Medicine.” New England Journal of Medicine, 6 Jan. 2000, doi:10.1056/nejm200003303421323</ref><ref>Pinker, Steven. Enlightenment Now: the Case for Reason, Science, Humanism and Progress. Penguin Books, 2019.</ref> Examples of these trends can be seen in the medical milestone timelines for the last [https://www.medicinenet.com/medical_milestones_in_the_past_500_years/views.htm 500 years], [https://www.keckmedicine.org/the-most-life-changing-health-advances-of-the-past-50-years/ 50 years], or [https://web.archive.org/web/20190529232120/https://www.syberscribe.com.au/blog/19-mind-blowing-medical-advances-in-the-past-8-years/ decade]. The size scale at which tissue repairs can be performed has also become smaller over time, with cellular and molecular scale tissue repairs only recently becoming possible. Examples of tissue repairs at these scales are therapeutic gene editing, stem cell technologies, organ 3-D printing, and cancer immunotherapies. The historic trends for medical technologies to become increasingly capable, at increasingly smaller scales, implies that future medical technologies could possibly or even likely be more capable of repairing damaged tissues than they are today. However, it is generally very difficult to accurately predict the capabilities or limits of future technologies, especially when trying to forecast more than a decade or so into the future.<ref>Quinn, James Brian. “Technological Forecasting.” Harvard Business Review, 1 Aug. 2014, <nowiki>https://hbr.org/1967/03/technological-forecasting</nowiki>.</ref><ref>Loeffler, John. “29 Terrible Predictions About Future Technology.” Interesting Engineering, 12 Feb. 2019, https://interestingengineering.com/29-terrible-predictions-about-future-technology</ref><ref name=":13">Epstein, David. “The Peculiar Blindness of Experts.” The Atlantic, 20 May 2019, https://www.theatlantic.com/magazine/archive/2019/06/how-to-predict-the-future/588040/</ref>

==== Unknown: How much of the human mind is preserved during cryopreservation? (How much damage occurs?) ====

It is not yet known how much of the neurological basis of the mind is preserved using current cryopreservation technologies. Cryonics cooldown and rewarming procedures do cause some amount of tissue damage. The amount of damage is estimated to be relatively small in some cases, and larger in other cases, depending on the circumstances and techniques that were used with each particular cryonics patient. There is reason to believe that with the best currently achievable vitrification procedures, and the best cryopreservation timelines, that the small-scale neurological structures of the brain are preserved very well.<ref name=":7" /><ref>Fahy, G.m., et al. “Vitrification as an Approach to Cryopreservation.” Cryobiology, 1984, doi:10.1016/0011-2240(84)90079-8.</ref><ref name=":5" /> At the other end of the spectrum, the amount of neurological tissue damage increases whenever a particular cryopreservation is significantly delayed, or when a "straight freezing" process is performed instead of a vitrification. One reason it is difficult to quantify how much of the mind is preserved using current cryonics procedures, is that the neurological basis of the human mind is not yet completely understood by science.<ref name=":8" /> The current research into how human personality and memories are biologically encoded is still in its early stages. Hypothetically, if there is a partial loss of neurological information caused by tissue damage, then a cryonics patient may have partial loss of preexisting behaviors or memories after repair and revival.<ref>Merkle, Ralph C. “Will Cryonics Work?” Merkle.com, 2019, https://web.archive.org/web/20190702182723/http://www.merkle.com/cryo/probability.html</ref><ref name=":9" />

==== Unknown: How much tissue damage will be repairable by future medical technologies? (Are comprehensive repairs feasible?) ====

Predicting the capabilities of future technologies is inherently difficult.<ref name=":13" /> Historically, medical repair technologies have become [[Cryonics#Known: Medical repair technologies have historically tended to become more capable over time.|increasingly capable over time]]. Some scientists claim that medical technologies can be foreseen, such as nanotechnology, and detailed tissue regeneration, which may be able to repair the tissue damage that is caused by current cryopreservation technologies.<ref name=":3" /> Other scientists are skeptical that sufficiently advanced medical technologies will ever exist.<ref name=":12" /> In general, there is no way to predict for certain the capabilities and limits of future technologies, until the time that those technologies are developed.

==== Unknown: Will the cryonics organizations survive long enough for repair technologies to mature? (How long could that take?) ====

No one knows how long it could take before advanced molecular scale medical repair technologies are developed, or if they will be developed at all. If such technology does become possible, it could take decades or even centuries. It's unknown how long cryonics storage organizations can continue to survive, and can maintain their patients in liquid nitrogen. So far, the longest that any human has been cryopreserved is about 53 years, as of 2020. Within that timeframe, the two largest cryonics organizations (Alcor and the Cryonics Institute), have had a consistent record of maintaining their cryonics patients at liquid nitrogen temperatures.<ref>Best, Ben. “A History of Cryonics.” Benbest.com, https://www.benbest.com/cryonics/history.html</ref><ref name=":10" /><ref name=":11" />

== Past Revivals of Whole Organisms ==

Various living organisms have been successfully revived after freezing, either in the lab or in nature. Medical and laboratory revivals of whole organisms have included Human embryos, adult C. Elegans, and fly larvae.<ref name=":4" /><ref name=":5" /><ref name=":6" /> Notably, it is not yet possible to revive humans who were cryopreserved after the embryonic stage. The process of cooling to cryogenic temperatures tends to create conditions for tissue and cellular damage, but while cryogenic temperatures are maintained, little to no damage occurs.

Human embryos are routinely cryopreserved in medicine for assisted human reproduction. Embryos are most commonly vitrified at the blastocyst stage, which is 3-days or 5-days after conception. Slow cooling techniques were first used to freeze viable embryos starting in 1984. The first birth from a cryopreserved embryo occurred in 1998. Since then, the cryopreservation of embryos has become increasingly common, due to improved embryonic survival rates and better clinical outcomes.<ref name=":4" /> In 2017, a healthy baby girl, Emma Wren Gibson, was born after being cryopreserved as an embryo for 24 years.<ref>“'Longest-Frozen' Embryo Born 24 Years On.” BBC News, 20 Dec. 2017, https://www.bbc.com/news/world-us-canada-42420864</ref> That was a record for the longest time a human embryo had been cryopreserved before a revival and a live birth.

== Memory Retention Experiments ==

In 2015, it was demonstrated for the first time that memories can be retained after the cryopreservation of a whole organism. Adult Caenorhabditis Elegans nematode worms were instilled with memories of specific chemical odors. They were then cryopreserved in liquid nitrogen, and revived. After revival, they were tested for the retention of the odor memories, and it was shown that the memories were still present.<ref name=":5" />

== Cryopreservation Procedures ==

A standard cryopreservation procedure<ref>"Introduction to Alcor Procedures", Alcor Life Extension Foundation, https://www.alcor.org/library/introduction-to-alcor-procedures/</ref><ref>"Guide to Cryonics Procedures", Cryonics Institute, https://www.cryonics.org/ci-landing/guide-to-cryonics-procedures/</ref> has six phases:

# '''Standby:''' As a dying patient’s condition becomes critical, transport personnel wait nearby on a 24-hour basis.
# '''Stabilization:''' The patient is placed in an ice water bath, and breathing and circulation are artificially restored with a heart-lung resuscitator. Protective medications are also administered, including free radical inhibitors, anticoagulants, and anesthetics.
# '''Transport:''' After stabilization, patients will be transported to their cryonics facility.
# '''Cryoprotective Perfusion:''' Major blood vessels are connected to a perfusion circuit by a surgeon. A preservation solution circulated through the patient at a temperature near 0°C.
# '''Final Cooldown:''' After cryoprotective perfusion, patients are cooled under computer control by fans circulating nitrogen gas at a temperature near -125°C.
# '''Storage:''' Patients are placed into vacuum-insulated dewars, where they are stored in liquid nitrogen at a temperature of -196°C.

These phases describe a standard cryopreservation protocol. However, the circumstances surrounding a person's death can differ from person to person, and therefore the standard protocol is sometimes modified depending on the circumstances surrounding a person's death. An example of modified protocol is a "Straight Freeze" procedure. A straight freeze is the freezing of a cryonics patient to liquid nitrogen temperatures without introducing cryoprotectants. This can be performed in cases where cryoprotective perfusion is no longer feasible. A straight freeze procedure is less desirable that the standard protocols, because a freezing without cryoprotectants causes small ice crystals to form in the body from the water in tissues. Those crystals cause significant damage to the cellular membranes in the brain, and in other tissues of the body.

During the first two phases (stabilization and transport), time is of the essence. Ideally, the stabilization phase will begin within seconds of the pronouncement of a person's clinical death. Clinical death refers to the cessation of heartbeat and respiration. The transport phase should also proceed as quickly as possible. In an idealized cryopreservation procedure the transport phase can be minimized or eliminated. This can be accomplished if 1) the person relocates to the same city as their cryonics facility at some point before death occurs, or 2) if a field cryoprotection procedure is performed.

The reason it is desirable to start the perfusion and final cooldown phases as quickly as possible after clinical death, is to better preserve the fine cellular structures in the brain. These neural structures are commonly thought to encode for the major aspects of a person's identity, such as memory and personality.

==References==
<references />

Cryonics

2021-09-06T23:53:40Z

BLife:

Cryonics

2021-09-06T23:52:52Z

BLife: Added section, Cryopreservation Procedures

Cryonics

2021-09-06T23:32:52Z

BLife: /* Memory Retention After Revival in Experiments */

Cryonics

2021-09-06T23:31:29Z

BLife: /* Memory Retention After Revival */

Cryonics

2021-09-06T23:26:16Z

BLife: /* Revivals of Whole Organisms */

Cryonics

2021-09-06T23:24:50Z

BLife: adding citations

Cryonics

2021-09-06T23:18:06Z

BLife: Added section, Revivals of Whole Organisms

Cryonics

2021-09-06T23:13:07Z

BLife: adding citations

Cryonics

2021-09-06T23:07:05Z

BLife: adding citations

Cryonics

2021-09-06T22:58:58Z

BLife: adding links and citations

Information theoretic death

2021-09-06T22:42:01Z

BLife: added to glossary category

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:

A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.

The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

"Information-theoretic death" also arises in the context of cryonics, which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. The use of information-theoretic criteria has formed the basis of ethical arguments that state that cryonics is an attempt to save lives rather than being an interment method for the dead. In contrast, if cryonics cannot be applied before information-theoretic death occurs, or if the cryopreservation procedure itself causes information-theoretic death, then cryonics is not feasible.

== External Links ==

* Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
* Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
* Ethics review: Dark angels-- the problem of death in intensive care (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
* Albert Einstein’s brain and information-theoretic death (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

== References ==
<references />
[[Category:Glossary]]

Information theoretic death

2021-09-06T22:40:55Z

BLife: fixed some broken external links

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:

A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.

The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

"Information-theoretic death" also arises in the context of cryonics, which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. The use of information-theoretic criteria has formed the basis of ethical arguments that state that cryonics is an attempt to save lives rather than being an interment method for the dead. In contrast, if cryonics cannot be applied before information-theoretic death occurs, or if the cryopreservation procedure itself causes information-theoretic death, then cryonics is not feasible.

== External Links ==

* Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
* Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
* Ethics review: Dark angels-- the problem of death in intensive care (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151911/)
* Albert Einstein’s brain and information-theoretic death (https://www.biostasis.com/albert-einsteins-brain-and-information-theoretic-death/)

== References ==
<references />

Information theoretic death

2021-09-06T22:35:52Z

BLife: added citation

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain"<ref>Ralph C. Merkle, “Molecular Repair of the Brain,” '''Cryonics''' 10(October 1989):21-44</ref> by Ralph Merkle defined information-theoretic death as follows:

A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.

The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

"Information-theoretic death" also arises in the context of cryonics, which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. The use of information-theoretic criteria has formed the basis of ethical arguments that state that cryonics is an attempt to save lives rather than being an interment method for the dead. In contrast, if cryonics cannot be applied before information-theoretic death occurs, or if the cryopreservation procedure itself causes information-theoretic death, then cryonics is not feasible.

== External Links ==

* Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
* Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
* Ethics review: Dark angels-- the problem of death in intensive care (http://nereja.free.fr/files/DarkAngels.pdf)
* Albert Einstein’s brain and information-theoretic death (http://www.depressedmetabolism.com/2008/06/01/albert-einsteins-brain-and-information-theoretic-death/)

== References ==
<references />

Information theoretic death

2021-09-06T22:32:28Z

BLife: Added external links

Information-theoretic death is the destruction of the human brain, and information within it, to such an extent that recovery of the original mind and person that occupied the brain is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest, become reversible and are no longer considered to be death.

"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death and legal death, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory.

The paper "Molecular Repair of the Brain" by Ralph Merkle defined information-theoretic death as follows:

A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.

The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after several hours of clinical death at room temperature as the brain undergoes autolysis. It can also occur if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death, or during the progression of degenerative brain diseases that cause extensive loss of brain structure.

"Information-theoretic death" also arises in the context of cryonics, which can be viewed as the use of cryopreservation to attempt to prevent information-theoretic death. The use of information-theoretic criteria has formed the basis of ethical arguments that state that cryonics is an attempt to save lives rather than being an interment method for the dead. In contrast, if cryonics cannot be applied before information-theoretic death occurs, or if the cryopreservation procedure itself causes information-theoretic death, then cryonics is not feasible.

== External Links ==

* Molecular Repair of the Brain (http://www.alcor.org/Library/html/MolecularRepairOfTheBrain.htm)
* Pro/con ethics debate: When is dead really dead? (http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07)
* Ethics review: Dark angels-- the problem of death in intensive care (http://nereja.free.fr/files/DarkAngels.pdf)
* Albert Einstein’s brain and information-theoretic death (http://www.depressedmetabolism.com/2008/06/01/albert-einsteins-brain-and-information-theoretic-death/)

== References ==
<references />