X-Message-Number: 9153
From: Thomas Donaldson <>
Subject: Re: CryoNet #9142 - #9148
Date: Wed, 11 Feb 1998 21:12:48 -0800 (PST)

Hi everyone!

To Mr. Strout: 
(Well, I really thought you were a PhD, but it doesn't matter). 
Your answer raises further questions. If this reconstructed machine into which
your memories have somehow been implanted is at the same scale as you are,
then I do not understand just why you believe we can work so finely (nano-
finely, so to speak) with this machine but somehow cannot do the same with
biological objects such as brains. One initial thought was the idea that
perhaps you felt that we understood matter at that scale, for electronics
purposes, well enough or close to well enough already, but did not understand
how brains worked at that scale. However there is a problem there: we can
hardly make an electronic machine containing your memories unless we know
how to read off the memories inside brains --- and for cryonics purposes,
damaged brains, too.

It should be clear that no essential barrier prevents us from working with
biological material using tools which are not biological. Any biolab in 
any university will show that. We do have to understand what we're doing,
when we work with these things, and at the lower levels we have now a 
better understanding of computer memories than of brain memories --- but
that is irrelevant to the problem, which requires that we understand 
brain memories to remake you in any form at all.

Or is YOU to be merely something which looks like you and superficially
behaves like you? I don't believe you meant it so simply.

There is, just to add a bit of likelihood to this picture, a growing 
sense that long term memory formation occurs by the creation of new 
synapses and new connections. Cf the recent article in SCIENCE, ER Kandel
et al (270(1998) 338-341) for a discussion of this in Aplysia in a different
context. With references. This suggests to me that the current electronic
neural nets won't match brains in their behavior (NOTE that I say nothing
here about speed). If we create a device capable of imitating your brain
on the scale at which your memories are stored, then that device will have
to have some ability to grow and change, and not in any fixed mode (ie.
turn on connections already there, for instance).

So why is it that you believe we can make electronic (or light, or other)
networks of connections to match that of our brain, but cannot do so with
biological tissue? I know we can't do this now, but the question is that
of what is possible IN PRINCIPLE. And I will add that we at present don't
know enough to make even a small "brain" of anything at all --- electronic
or not. 

Of course one major feature of biological tissue is that it is floppy, and
wet, and moves around all the time (when it's alive). But then I find it hard
to imagine remaking YOU (or me) into something which does not have such
features. And the insights in Aplysia memory suggest that such behavior
is essential to us, not just a side effect of the way we are made. It does
have its advantages, as you know --- even on a simple level. If I get
dings and scratches they heal over, while if your car, television, or
computer gets dings and scratches they stay there forever. And please be
careful: I am not claiming here that creatures able to carry out such
self repair must necessarily be composed of the same materials and systems
as we are. But it IS an advantage, especially if we want to survive a 
long time.

So over to you on this issue.

				Best wishes and long long life,

					Thomas Donaldson

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