A Taxonomy of Immortality
Those folk who aspire to immortality - in the sense of "living a really long time without aging to death, and working out some of the details later" - would do well to spend a little time thinking about a taxonomy of this much abused word: "In 'Philosophical Models of Immortality in Science Fiction,' (in: Immortal Engines: Life Extension and Immortality in Science Fiction and Fantasy) John Martin Fischer and Ruth Curl construct a taxonomy for immortality. ... only some models of immortality meet the criterion of real personal immortality in which an individual leads an indefinitely long single life ... If we leave the issue of solipsistic and non-solipsistic immortality to the side (see David Deutsch on solipsism), the only mature method listed to achieve immortality which is available right now is cryonics. Strictly speaking, cryonics itself does not achieve immortality, but it can enable a person to reach a time when technologies that can produce immortality may be available. ... Even individuals who hope to benefit from SENS and have made arrangements for cryonics live in a world with a non-trivial probability of information-theoretic death. Minimizing the probability of information-theoretic death should be the objective of radical life extension."
Link: http://www.depressedmetabolism.com/2008/06/08/immortality-and-cryonics/