X-Message-Number: 24841 Subject: Re: physical immortality possible? From: Aubrey de Grey <> Date: Sun, 17 Oct 2004 13:08:20 +0100 Readers may not all be aware that a parallel discussion, initiated in part by Ben's essay and in part by a related one by Reason posted at Longevity Meme on September 20th, is occurring at ImmInst. Bruce has been cross-posting some of the Cryonet posts to that debate, but there is too much to cross-post it all in the other direction, so please go and have a look: http://www.imminst.org/forum/index.php?s=&act=ST&f=106&t=4298&st=0 One thing that has come up is related to what David writes. The basic thesis of his post, i.e. that we can live genuinely *forever*, seems contrary to basic principles: even if we totally eliminate aging, we still have a "half-life" and thus a very small chance of living a very long time, and indeed an exactly zero chance of never dying at all. But if (as David alludes to) we continue to increase our "half-life" as time goes on, that turns out not to be so: the asymptote of our survival probability graph is not zero. (I did a worked example at ImmInst.) This does, as David notes, rely on the Universe not having the last laugh by udergoing heat death or whatever, but discussion of that in the context of current physics is too speculative to detain us when we recall that (again, as David says) the only real point of this line of thought is to invigorate our short-term efforts. Where David goes wrong is to suggest that involuntary death will ever be conquered, in the true sense of the achievement of a *zero* chance of ever dying involuntarily (or even a zero chance in the coming year). The discussion at ImmInst is largely about this terminological issue. Aubrey de Grey Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=24841