Is there a way to pause death and then, at some future time, reverse it? And if there is, when and how can we do it? These questions are particularly relevant to the topic of cryonics aka human cryopreservation. This is the practice of preserving a patient right after their legal death, pausing the degradation process. Once medical technology has developed to a point where it can treat the causes of death, the patient will possibly be revived and live an extended life in the future. But this can only be achieved if we start from the assumption that death is reversible…
To find an answer to our questions we first need to understand what it means to be dead. Traditionally, death was viewed as a single moment. At one point someone is completely alive and at the next, they are completely dead. The idea that death is a single moment has been widely accepted for centuries. But let's examine this assumption more closely.
If you had been walking down the street in 1950 and your heart stopped, you would have been considered dead. Only 10 years later, with the development of CPR, this would no longer be the case. Today, someone's heart can stop for a few minutes and still be resuscitated. Someone considered dead in 1950 could have been saved and gone on to live a healthy life with today's medical practices. So, if a person's heart stopped in 1950, were they really dead?
We would say no. They were not really dead, they just weren't savable with the medical technology of the specific time in which they "died." When someone dies today, what it really means is that there is nothing more that current medical technology can do to help them.
Just as someone who was considered completely dead in 1950 could have potentially been saved today, it's possible that someone who is considered completely dead today could be saved by the medical practices of the future.
As our medical technology has advanced, so has our definition of death. From the perspective of an individual's lifespan, it is easy to see death as this inevitable moment. Something that has remained constant and inescapable throughout our history. However, when we step back and look at the progress of medical practices over long periods of time, we quickly see our assumptions about death challenged.
Today, someone is considered "dead" when their heart stops for 4-6 minutes. This is how long the brain can go without oxygen before our current technology cannot save them. New experimental treatments have been able to prevent brain damage even after more than 10 minutes of cardiac arrest. It is widely expected that molecular repair technologies in the future may extend the boundaries of resuscitation well beyond 10 minutes. The current definition of death is already becoming obsolete.
After legal death, biological processes still occur in the body. As oxygen is depleted, cells slowly begin the process of self recycling. Depending on the conditions (and temperature ...) of the body, this process can be slowed down significantly and even stop. The fact is that death is not a moment, it is a process. If that process can be paused, then perhaps they are not really "dead". This is the fundamental idea behind cryonics. Cryonics can put the body into a complete biological pause just after legal death. We may not be able to treat cryopreservation patients today, but if we pause the dying process, these patients may live to see a world that can save them.
There is no fundamental biological reason why revival after cryopreservation is not possible. Death and its causes aren't necessarily an insurmountable inevitability; they are a series of individual problems that can be solved. Proponents of cryonics are well aware that there are many challenges to overcome before restoration of life is possible. However, the fact that these life-saving technologies are not yet available and may be difficult for some people to imagine, does not mean that they will never be available. We see today's technological achievements as obvious evolutions of our past technology, but if you took someone out of the 19th century, they would see what we have achieved as nothing short of magic.
So is death reversible? The honest answer is that we don't know. We probably won't know the answer to that question in our natural life. In a sense, cryonics is a grand experiment and we won't know if it will succeed for another century or so. The question to ask yourself is: would you rather be in the control group or the experimental group? By default, we are all resigned to permanent death in the control group. But if you are reading this, then you are at least somewhat aware of what cryonics is, which means that you are presented with the rare opportunity to consciously choose which group you want to be in. It is now in your hands to make that choice.