X-Message-Number: 17481 Date: Sat, 8 Sep 2001 10:20:12 -0400 From: Thomas Donaldson <> Subject: comments on 3 subjects Hi everyone! Well well ... some good questions and claims, this time. First of all, for Fabio, who asks how early the possibility of cryonic suspension began to look real: I was young at this time, and hardly someone who saw everything that happened. However so far as I understand, the idea of cryonic suspension required not just the notion that very low temperature might freeze life, but that it might preserve at least good clues to our MEMORY. This means that it could not have come about before the early 50's, when cryobiologists froze the brains of animals such as guinea pigs (not as low at LN at all, but just below 0 C) and showed that they remembered events happening beforehand. The important point here is that at such temperatures a brain behaves as if it's dead, with no metabolism. I believe Audrey Smith was the earliest to do this, but Isamu Suda carried this work further by freezing brains to lower temperatures (in the 1970's without full revival). Ettinger's book THE PROSPECT OF IMMORTALITY appeared not so long after Audrey Smith, in 1964. In any case, the likelihood that freezing would NOT destroy memory had been established when Ettinger's book appeared. Incidentally, the Immortalist Society still sells that book, and Ettinger hasn't yet been frozen and you can consult him directly. His book is a bit out of date on technology, but discusses several other important factors about cryonics better than anything so far done afterwards. Second, for Mike Perry: miserable explanation. I too believe that the structure and operation of our nervous system is critical to our survival, and that any device which imitates it in the right way will be living. However this has nothing to do with whether or not the device itself can tell the difference. Just as Ettinger says, if the device lacks the required structural characteristics, then whether or not it "thinks" itself real doesn't matter. By now we can say that it must be a net of processors, with each processor not simple at all, and with the ability to reproduce itself under the right circumstances and change its connections under other circumstances. We're coming close to being able to specify those circumstances more precisely, too. I will point out that as of the present time (2001) no one has actually made a system with all the required traits, and it's unlikely that merely being a neural net would be enough... though it might be enough to serve as the brain of an insect, for instance. My difference from Ettinger comes from the belief that brains are not the only devices that might become aware and intelligent. We can imagine other devices with quite different metabolism but an underlying structure like that of our own brains. Current neural nets and computers, however, are very unlikely to have such such abilities, no matter how much work goes into them. (I'm aware that Ettinger isn't quite so strong as to say such things are impossible, but he does require more than superficial similarities). Finally, though I am repeating myself, our revival does not require that "future society" be willing to revive us. It requires only that some group in that future society be willing to do so. We now call such groups "cryonic societies", and I see no reason to stop doing so. And the need for some form of suspension will be with us indefinitely ... it will not disappear when we can cure all our current diseases, including old age. We'll find plenty of others after living to 500 years, or 1000, or however long we may live: conditions incurable when they happen but which someday will become curable. I believe that these give some answers to questions raised. I'd like Bob Ettinger to tell more about the early history of cryonics as he himself saw it. He's become worth consulting from his age alone, and he wrote one of the earliest books on the subject. Best wishes and long long life to all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=17481