Cryonics is the practice of preserving humans or animals at extremely low temperatures with the hope of reviving them in the future when medical technology has advanced enough to cure currently incurable diseases or reverse death. It involves cooling the body, or just the brain in some cases, to a temperature where all biological activity, including the processes that cause decay, is effectively halted. The goal of cryonics is not to resuscitate the patient in the present but to preserve them until future technologies may offer solutions for the conditions that led to their death.
Cryonics is often associated with science fiction, but it is a real practice, albeit controversial. It is based on the idea that biological death, as we currently define it, might not be the end of life but rather a condition from which people could potentially be revived. Although no one has yet been successfully revived from cryonic preservation, cryonicists believe that the advances in medicine, artificial intelligence, and nanotechnology may eventually allow for such an achievement.
In this article, we’ll explore what cryonics is, how it works, the scientific principles behind it, the current state of cryonic preservation, and the ethical, legal, and practical challenges it faces.
The Origins of Cryonics
The concept of cryonics dates back to the 1960s, when Robert Ettinger, a physics teacher and author, published The Prospect of Immortality in 1962. In this seminal book, Ettinger proposed that people who die today could be preserved through cryopreservation and then revived in the future when medical science has advanced sufficiently. His ideas were inspired by emerging research in low-temperature biology, specifically the ability to freeze and preserve small organisms like bacteria and invertebrates, and by science fiction literature that envisioned the possibility of suspended animation.
Ettinger’s vision inspired the establishment of cryonics organizations, such as the Cryonics Institute (which he founded in 1976) and Alcor Life Extension Foundation (founded in 1972). These organizations offered the opportunity for individuals to be cryopreserved after legal death, with the hope of future revival.
While Ettinger’s ideas were met with skepticism from the medical and scientific communities, they also garnered interest from people fascinated by the possibility of extending life or deferring death until a time when technology could reverse it.
How Does Cryonics Work?
Cryonics involves several key processes, each designed to preserve the patient’s body, or at least their brain, in a way that halts biological decay and deterioration. This preservation process happens in the following stages:
1. Legal Death Declaration
Cryonic preservation can only begin after a person has been legally declared dead. In the context of cryonics, legal death means that the heart has stopped beating and the person is no longer able to be resuscitated by current medical techniques. However, cryonicists believe that at this stage, biological death—the irreversible cessation of all brain activity—has not yet occurred. This distinction is important because, according to cryonics advocates, it means that the person could potentially be revived in the future.
Once legal death is declared, a cryonics team must act quickly to begin the preservation process. This is because, even though legal death has been declared, biological tissues (especially brain tissue) can begin to degrade rapidly if not cooled down in time.
2. Stabilization and Cooling
Immediately after legal death is declared, the cryonics team begins stabilization procedures to maintain the body in a state that minimizes further damage. This involves cooling the body as quickly as possible to slow down metabolic processes and prevent decay.
At this stage, the team may begin cardiopulmonary support to artificially circulate blood and oxygen to the brain, helping to preserve the tissues for as long as possible. The goal is to keep the organs viable until the body can be prepared for deeper cooling.
The patient’s body is then cooled using ice water or other methods to bring the temperature down toward freezing without causing immediate cellular damage. The rapid cooling reduces the activity of enzymes and bacteria that could otherwise cause tissue breakdown.
3. Cryoprotectant Perfusion (Vitrification)
One of the biggest challenges of cryopreservation is preventing ice formation in the body’s tissues. When biological tissues freeze, the water inside cells can form ice crystals, which expand and damage cell membranes and other structures. This damage can be catastrophic, making future revival impossible.
To prevent this, cryonics organizations use a process called vitrification, which involves replacing the blood and other bodily fluids with a cryoprotectant solution. Cryoprotectants are chemicals that reduce the formation of ice crystals by turning the water in cells into a glass-like solid rather than ice. This process minimizes the mechanical damage caused by freezing.
The most common cryoprotectants used in cryonics are ethylene glycol or dimethyl sulfoxide (DMSO). These substances are perfused (circulated) through the patient’s bloodstream, gradually replacing the water in the tissues. When the body is subsequently cooled to extremely low temperatures (around -196°C or -320°F), the cryoprotectant ensures that the body enters a vitrified state rather than freezing solid.
4. Long-Term Storage in Liquid Nitrogen
Once the body has been vitrified, it is slowly cooled to cryogenic temperatures and placed in a cryostat—a large insulated container filled with liquid nitrogen. The body (or brain, depending on the patient’s choice) is stored at temperatures around -196°C, where all biological processes are effectively halted.
At this temperature, the metabolic processes that cause decay and decomposition stop entirely, and the body can theoretically remain in this preserved state indefinitely. The cryostat is designed to maintain these temperatures with minimal intervention, and regular refills of liquid nitrogen are needed to ensure the preservation continues.
5. Revival (Theoretical Future Technology)
The final and most speculative stage of cryonics is revival, which remains purely theoretical at this time. Cryonics organizations are not yet able to bring a preserved patient back to life. The hope is that future advances in nanotechnology, regenerative medicine, artificial intelligence, and medical science will make it possible to:
- Repair cellular and tissue damage caused by the preservation process.
- Cure the disease or condition that originally caused the patient’s death.
- Restore neurological function, especially in the brain, to allow for the return of consciousness and memory.
Some cryonicists believe that molecular nanotechnology, a field that envisions the creation of machines on the atomic scale, could be used to repair cells and tissues at the molecular level. This would include fixing any damage caused by freezing or disease, essentially reversing the aging or death process.
While this is still a distant hope, advancements in areas like stem cell research, biotechnology, and neuroscience are often cited by cryonicists as steps toward the potential revival of cryopreserved individuals.
Types of Cryonics: Whole Body vs. Neurocryopreservation
There are two primary types of cryonics preservation that individuals can choose from:
- Whole-Body Cryopreservation: In this method, the entire body is preserved at cryogenic temperatures. The rationale behind whole-body preservation is that all parts of the body, including the brain and organs, may one day be repairable or replaceable. This method is more expensive due to the need for larger storage facilities and more cryoprotectants.
- Neurocryopreservation: In this method, only the brain or head is preserved. This option is based on the belief that the brain holds the personality, memories, and consciousness of an individual, and that the rest of the body can be replaced or regenerated in the future. Neurocryopreservation is often chosen as a lower-cost option, with the assumption that the brain is the most critical part of the body to preserve.
The Science Behind Cryonics: Is It Feasible?
While the idea of cryonics is appealing to those who want to extend their lives or avoid death, it remains a controversial and unproven practice. Critics argue that there is no scientific evidence to support the idea that cryopreserved individuals can be revived in the future. There are several scientific challenges and unknowns that make cryonics highly speculative at best:
1. Damage from Cryopreservation
Even with the use of cryoprotectants, the process of cooling the body to cryogenic temperatures can cause significant damage to cells and tissues. While vitrification reduces ice crystal formation, it does not eliminate it entirely, and some level of damage is inevitable. Currently, there is no known way to reverse this damage or repair cells that have been damaged by the freezing process.
2. Complexity of the Human Brain
The human brain is an incredibly complex organ, and its functions—particularly those related to memory, consciousness, and personality—are not fully understood. Even if a preserved brain could be revived, it is unclear whether the person’s memories or sense of self could be restored. Cryonicists argue that future advances in neuroscience might allow for the repair or regeneration of damaged brain tissue, but this remains speculative.
3. Current State of Technology
At present, medical science is far from being able to repair or regenerate whole organs or reverse the processes of death. While regenerative medicine and stem cell research are making advances, the ability to revive cryopreserved individuals is beyond the reach of current technology. Cryonicists are betting on breakthroughs in fields like nanotechnology and artificial intelligence, but these technologies are still in their infancy.
Legal and Ethical Considerations
Cryonics raises a number of legal and ethical questions, particularly surrounding the definition of death and the rights of individuals who have been cryopreserved.
1. Definition of Death
In cryonics, the preservation process begins after a person has been declared legally dead. However, cryonicists argue that current definitions of death—based on the cessation of heartbeat or brain activity—are too rigid. They suggest that “death” may be reversible in the future with the right technologies. This raises ethical questions about when it is appropriate to begin preservation and how to define death in the context of potential future revival.
2. Consent and Autonomy
For cryonics to be carried out, the individual must give informed consent before their death. This means they must understand the speculative nature of cryonics and agree to be cryopreserved with the understanding that there is no guarantee of revival. Additionally, there are cases where family members may disagree with a person’s wish to be cryopreserved, leading to legal disputes over consent and burial rights.
3. Financial Considerations
Cryonics is a costly process, with whole-body preservation often costing $150,000 or more and neurocryopreservation around $80,000. Some individuals use life insurance policies to fund their cryopreservation, naming the cryonics organization as the beneficiary. However, maintaining the cryogenic facilities and ensuring the long-term preservation of patients requires ongoing financial support, which raises concerns about the sustainability of cryonics organizations over the decades (or centuries) it might take for revival to become possible.
4. Ethical Concerns About Future Revival
Even if future technologies allow for the revival of cryopreserved individuals, there are ethical questions about what kind of life they would return to. Would they have the same legal rights? Would they be integrated back into society? What if the world they wake up in is drastically different from the one they left behind? These questions remain speculative but are worth considering as the field of cryonics continues to evolve.
Cryonics Today: Current State and Challenges
As of today, no one has been successfully revived from cryonic preservation. However, there are several organizations that continue to offer cryonics services to individuals who wish to be preserved after death. The two largest and most well-known cryonics organizations are:
- Alcor Life Extension Foundation: Based in Arizona, Alcor is one of the leading cryonics organizations, offering both whole-body and neurocryopreservation services.
- Cryonics Institute: Founded by Robert Ettinger, the Cryonics Institute is based in Michigan and offers whole-body cryopreservation at a lower cost than Alcor.
Both organizations maintain facilities where patients are stored in cryostats at cryogenic temperatures, awaiting future technologies that may one day enable revival.
Despite its growth, cryonics remains controversial and is often viewed skeptically by the medical and scientific communities. Critics argue that it offers false hope to individuals seeking immortality, while proponents see it as a legitimate extension of life-extension technologies.
Conclusion
Cryonics is a highly speculative practice that aims to preserve individuals at extremely low temperatures in the hope that future medical technologies will one day allow for their revival. While the concept of cryonics is grounded in the desire to extend life and overcome death, it remains fraught with scientific, ethical, and practical challenges.
For now, cryonics offers the possibility—not the promise—of a second chance at life in the distant future. Whether that possibility will ever become a reality remains to be seen, but for those who believe in the potential of science and technology to reverse death, cryonics represents a unique and fascinating frontier in the quest to defy the limitations of the human lifespan.
