X-Message-Number: 11798
From: Thomas Donaldson <>
Subject: Answer to Mike Perry plus longer discussion for Daniel Crevier
Date: Sat, 22 May 1999 23:30:32 +1000 (EST)

For Mike Perry:
My reason for saying that dreams are not the same as virtual consciousness
is simple. They DO depend on previous consciousness, and persist for only
a finite length of time. It isn't sufficient to keep a brain only
TEMPORARILY isolated to make its thinking virtual. If I go into my
room, lie down, and close my eyes to think about something, I am just 
as isolated, but that is hardly the same as the long term isolation of
a "virtual person" (if such is possible) in a computer.

There is, of course, also the simple point that it is only for unproved
theoretical reasons that the behavior of a living brain can be imitated
by a computer (highly parallel or not). And to say that these living 
brains occasionally pass through a period of virtual reality says nothing
about whether or not a computer could do so.

To Daniel Crevier:
I have discussed this issue several times in PERIASTRON. I can send you 
precise bibliographic information once I look it up, but basically an
article in the JOURNAL OF CHEMICAL NEUROANATOMY (I believe in 1998) showed
how we can distinguish at least 5 different kinds of interneuron solely on
the basis of whether or not they contained specific biochemical factors.
In two cases, the distinction lay in the ratio between two such factors
rather than any absolute level of containment.

Such information needs to be developed a good deal further; even those
studying such questions would agree. (I plan to report on several recent
articles looking at chemical neuroanatomy in the coming PERIASTRON ...
the 1 May issue, out towards the end of May). At its simplest level, such
information means that electron micrographs alone are unlikely to provide
enough information to decide whether or not a brain is revivable --- 
unless they show literally TOTAL destruction, which they do not.

As I've said, I'll have to look up the exact issue and article, and can
send that to you separately.

			Best and long long life to all,

				Thomas Donaldson

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