X-Message-Number: 8519
From: Thomas Donaldson <>
Subject: Re: CryoNet #8511 - #8514
Date: Mon, 1 Sep 1997 14:15:55 -0700 (PDT)

To Yvan:

About LN2, that's just not the way I understand it. Moreover, "corrosion"
at those temperatures, even if it happens, is hardly fast enough to matter.
Can you perhaps give some references on this?

About "uploading":

1. If we don't understand how brains work, then whatever pictures or other
   information we store might easily miss some very critical things. For
   instance, it's only very recently that neuroscientists realized that 
   some gases such as NO and CO could act as transmitters. So just how much
   are we losing when we "store" a brain in a computer?
 
2. I most certainly agree that we must still think about what to do with
   damaged patients. HOWEVER in that case, the problem of storage is still
   worse, since we have many different kinds of damage which will affect the
   brain of a patient in many different ways. Just what information to store
   and what to ignore, and in what form to store it, becomes important. The
   fact that some structures, features, or chemicals are NOT there becomes
   just as important as their presence. The setting: what was done to the
   patient in the past, as compared to their present state, also becomes
   important.

   While we will probably use very powerful computers to unravel all this
   about a damaged patient, I would prefer to filter (and possibly lose)
   information at the OTHER end rather than storing the damaged brain 
   now. Freezing it, with or without cryoprotectant, is one way to store
   it without making assumptions about what was there when the patient was
   alive and undamaged. (I make no assumptions here about future methods 
   for storage. But we must store people now).

3. About the problems of uploading: first of all, as I understand it, the
   present imaging technology might give a very gross view of a brain,
   but hardly do so at a microscopic level. X-rays don't obviously fix
   that problem, since their energy may well damage or change what we are
   trying to look at ... assuming in the first place that we could actually
   do the focusing required. We may well need a quite different technology,
   perhaps a system which inserts multiplying bacteria into the brain, each
   one of which attaches to a neuron, maps out its connections, and then
   leaves to report its results ... after which a computer puts them all
   together (that is a VERY simple statement of something which would have
   to be much more complex! and I also ignore many problems with it here).

4. If you think such patients will require uploading to be revived, I'd
   point out that even that is far from obvious. Yes, we'd need to work
   out the structure and chemistry of their damaged brain, in detail. We
   would also need a computer to figure out the undamaged structure and
   work out a plan for repair. Whether we then choose to recreate a brain
   with the former structure and chemistry, or fix the one we have, looks
   to me like a choice which would depend a lot on several different 
   things: just how much and how damaged was this brain? What kinds of 
   brain repair are now possible (ie. when the repair is done).

   As a subscriber to PERIASTRON, you know already that lots more repair
   potential exists in brains than neuroscientists formerly thought. Just
   what boundaries there might exist to affect our choice is something
   which should be settled AT THE TIME OF REPAIR.

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