Death is not a topic that people like to think about, and that is just as true of healthy life extension advocates as anyone else. We have to recognise, however, that the future of healthy life extension (regenerative medicine, stem cell therapies, understanding the biochemical processes of aging, and nanomedicine, to name a few fields) will not arrive soon enough to benefit everyone. Many people are too old, or suffer from other conditions that will kill them before cures can be developed. This is an unpleasant reality that we must face.
Do we just write these people off and forge ahead regardless? Of course not. Instead, we turn to the science and business of cryonics, a serious effort to solve this problem that has been underway since the early 1970s.
Cryonics is the only option for life extension open to many older and seriously ill people: those who cannot wait for the promised therapies of the next few decades. It is the science of placing humans and animals into a low-temperature, biologically unchanging state immediately after clinical death, with the expectation that advances in medical technology may eventually enable full restoration to life and health. A small industry of cryonics providers exists to freeze your body on death, in the hopes that future scientists (most likely using nanotechnology and nanomedicine) will be able to revive and repair you.
The practice of cryonics is an ongoing medical experiment with an unknown chance of success. Responsible cryonicists understand that cryonic suspension is an educated gamble. The chances are certainly better than zero, however, and as one wag noted, "the control group in this experiment isn't doing so well." By this, he was referring to the vast number of people who are cremated, buried or otherwise interred. The chances of any plausible future science restoring them is zero. Cryonic suspension is, after all, only the second worst thing that can happen to you.
Tyler Cowen points out the Robin Hanson paper on why cryonics remains an unpopular option and comments:
Alas, I am a cryonics pessimist and I have yet to sign up for the extant services. (It is an interesting exercise to sit down and calculate how much resurrection would be worth to you, your implicit probability expectation, and your value for the modest yearly fee; many people have to fudge the numbers to justify their absolute dismissal of the idea.) But I also am pretty sure that most people, including prospective donors, reject the idea for the wrong reasons.
If you are interested in learning more about cryonics, the Alcor website is a good place to start. The Alcor staff go over the basics, the facts and the myths in a very helpful, open and straightforward manner.
UPDATE: Here is another long, good post on cryonics and the rational choice to sign up.