Most life extensionists and transhumanists do not buy into many of the myths about cryonics. But one perspective that is sometimes voiced by futurists is that cryonics is a rational backup plan until aging is cured. This position has some serious shortcomings and potentially lethal implications.
Human cryopreservation is the practice of placing terminally ill patients who have exhausted contemporary medical treatments into long term cryogenic care, allowing them to benefit from future medical treatments. Although aging-associated diseases are an important cause of death, they are not the only cause of death. Even when biological aging becomes optional, a person will still be vulnerable to accidents and violence.
The mindset that cryonics will become redundant as soon as aging is conquered is especially dangerous when it leads (young) people to forgo or postpone making cryonics arrangements because they expect to benefit from rejuvenation technologies and dietary supplementation during their lifetime. This may not only reflect wishful thinking regarding the rate of progress in overcoming aging, but it will also leave them vulnerable to other causes of death.
As long as humans (or post-humans) are vulnerable to injury that cannot be treated with contemporary medical technologies, human cryopreservation will remain important as a form of critical care. In other words, as long as there can be situations that warrant metabolic arrest to avoid information-theoretic death, there is a need for cryonics or similar technologies to induce metabolic arrest, like molecular warm biostasis.
There are a lot of people who believe in the technical feasibility of cryonics and intend to make cryonics arrangements….when necessary. As cryonics observers know, this is an extremely risky attitude because when people need cryonics the most, they often are unable to communicate their wishes, may meet resistance from relatives who benefit from their not making cryonics arrangements, or lack financial resources because life insurance is no longer an option to fund cryonics.
The best time to make cryonics arrangements is when it seems least likely that you need them soon. This is also evidenced by the fact that young healthy people can get excellent rates on life insurance.