X-Message-Number: 12389
From: Thomas Donaldson <>
Subject: loss of memory
Date: Thu, 9 Sep 1999 21:54:30 +1000 (EST)


Since John de Rivaz has published your questions on Cryonet, and partially
answered them, I thought I'd add a bit myself.

You may or may not be aware that taking someone down to 0 C but NOT
freezing them will not affect their memory. This has actually been
experimentally proven with animals, even if it was done in the 1950's.
Audrey Smith, a prominent British cryobiologist of that time, looked at
whether taking several species of small animals down to 0 C but without
freezing would affect their memory. Animals treated in this way look
quite dead. However it turned out that they recovered their memory
after being warmed up. At the time this was seen as decisive evidence
that our memories did not depend on persistence of activity in our brain.
(Brains of these animals were electrically silent, as you can guess).

Right now there is lots of work going on by cryonicists to cut down
the damage caused by taking an animal (or a person) down to the LN2
temperatures required. One process now under investigation involves 
not freezing but using cryoprotectants which produce a glass at similarly
low temperatures. This cuts down on damage to a very great extent.

Some cryonicists believe that IF we can fund the research, we can 
produce cryonic suspensions for which memories PROVABLY persist in about
10 years. That won't be the whole of the problem, unfortunately. Cryonics
is a form of emergency medicine, and will probably remain that way
indefinitely; this means that the conditions of a particular suspension
need not be the same as one carried out with full warning and no legal
or other problems. The problem there is that we may be forced to use
methods which aren't the best at the time ... the only alternative is to
give up completely.

So a definition of death which specifies that you are dead if the
information in your brain has been destroyed remains important. Just what
conditions will and will not destroy that information in particular cases
remains unknown. It can be worked on, but most living cryonicists would
(for NOW) most support research on preserving it under the best possible 
conditions ... those to which I referred above by saying that we have a
chance of solving their problems in 10 years. We still feel an obligation
to work on the other cases, too, of course.

And you will note from my explanation that I (and any other cryonicist!)
prefer to take the cautious route of keeping anyone for whom we DID NOT
KNOW that information had been preserved rather than simply destroying
them because we happened at the time not to know how to fix them. We may
well find that we've kept in preservation some patients for whom we can
someday prove that they're actually dead; but to simply ASSUME someone is
dead because we happen not to be able to tell strikes me and other 
cryonicists as the height of inhumanity.

			Best wishes,

				Thomas Donaldson

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