Here's a transcript of a talk given last year by Aubrey de Grey on SENS, cryonics and selling the ideas, put together at the People Database project blog: "It seems to me that the technical feasibility of cryonics is hard to sell, because real people out there don't like arguments along the lines of 'It doesn't matter how hard it is, because we've got arbitrarily long.' ... Not for any good reason, you understand. Arguments involving small numbers like '2+2=4' are altogether more effective it seems. ... Ultimately we are talking about four different concepts here: rejuvenating the body, rejuvenating the brain, reviving the body from cryostasis, and reviving the brain from cryostasis. If rejuvenating the body isn't much harder than rejuvenating the brain, then that probably means that we can get from reviving the body from cryostasis to reviving the brain from cryostasis. The difference in difficulty there will be similar. If we can get from rejuvenation, the sort of thing that I work on, keeping people's organs going by maintenance when they're still functioning to reviving those organs from cryostasis, if that's not a terribly big leap, then perhaps it can be done for the brain. ... Similarly, if cryobiology is a legitimate, even admirable field, including cryopreservation and resuscitation of organs, then we shouldn't really have too much difficulty in believing that cryonics is technically feasible in the foreseeable future. I find that this argument works rather well."