X-Message-Number: 1614 From: (Thomas Donaldson) Subject: Re: cryonics: #1596-#1605 (2/2) Date: Wed, 13 Jan 93 23:53:06 PST Ralph Merkle's comments are basically levelheaded. I would like to add some more, though. First, and unfortunately, since we don't have the complete story of how memory is stored, we're not in a position to argue definitively that information theoretic survival does actually occur. Second, once we DO have that information, it will become very clear that we need far less information than Ralph proposes. Basically, we need whatever structures/chemistry allows us to infer the content of the patient's memories. Some interesting facts need pointing out: we already know that embryonic nervous systems recover quite well after freezing to LN2 temperatures. When nerve regeneration happens in those animals that support it, connections tend to be restored even if broken beforehand. The main reason our own nervous system can't achieve such levels of repair (as compared to the brains of salamanders, which SEEM (there is one published experiment and considerable anecdotal evidence) to survive quite massive damage, memory intact; or goldfish, that regenerate their eyes if the eye has been destroyed) is that we have chemicals which specifically halt regeneration. Blocking these experimentally in rats has led to partial regeneration of severed spinal cords. The axons involved, by some special process, manage to reconnect correctly when they reconnect. (All this is a matter of very active research!). One major way things may turn out to prove the cryonics case may turn out to come from the indirect implications of all this work on memory and regeneration. If we can actually point to structures in a frozen brain which consist of our memories, and describe also how the information about brain connections survives even though the connections themselves do not, then the case for repairability becomes very strong. (Too bad we can't do that now). Even though I'm professionally a mathematician, and certainly have no trouble following Ralph's calculations, and even think that some form of nanotechnological repair will take place (though it may well consist of means to beef up all the natural repair processes, and block any that normally prevent regeneration!), it seems to me that his points about mapping the location of individual molecules are really beside the point. Yes, no doubt that will become possible; but without survival of memory structures (which presently look like they include nerve cell connections), that ability will mean nothing. Frankly, that means to me that cryobiological research simply cannot be ignored. And the reason for that is NOT simply its effect on others, but in proving whether or not we will survive (and if not, in telling us what we might do so that we WILL survive!). Moreover, if research on memory were not presently going through such a boom, I would say the same for that subject too. But fortunately many neurophysiologists are busy doing that side of the job for us, right now. Best and a very long life (forever, if possible), Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=1614