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

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