X-Message-Number: 20039
Date: Fri, 13 Sep 2002 08:46:44 -0400
From: Thomas Donaldson <>
Subject: CryoNet #20034 - #20036

For James Swayze:

Unfortunately or not, I was not referring to any holographic theory of
memory, nor is that the common view of how memory works. Basically
(so the common view says) our memories are encoded by the existence
of connections between particular neurons. That is, a particular memory
consists of a set of such connections; it may be itself spread among
many neurons, with each holding a part of it, but depending on just
what it is a memory of, destruction of some of these connections 
would destroy the memory. In a way, neuroscientists have gone back
to an older theory which located abilities and memories in particular
regions of the brain; it's much more complex and sophisticated now
than that older theory, but in one way it's in the same family. Some
neuroscientists actually have proposed that particular memories 
are stored in just one neuron, though most would not go so far.
(Actual memories are quite complex, as anyone who does any introspection
will see).

To be blunt, most neuroscientists would now think Kurzweil was WRONG.
There was a period in the 60's and early 70's when some thought that
memories were stored in chemicals which spread widely through our
brains. This theory has now been disproven, but it may be the theory
which led Kurzweil to make his statement.

As I said at the end of my discussion, one major thing I have been 
doing in my newsletter PERIASTRON is considering experiments on
both memory and identity. If our neurons really do remain static
and with fixed connections for our whole life (like computer 
memories) then any attempt to revive someone from freezing (as
distinct from vitrification) would require tracing out and 
rejoining all those broken connections caused by freezing. That's
not impossible if we look in detail at how brains are put together,
but full abilities to do that may take some time. However there is
also evidence that our connections do not remain static over our
lifetime, which raises questions about this whole theory of memory.
Even growth of new neurons and replacement of old ones by new ones
raises such questions. So I do not think that the most common present
theory of memory will keep its present leading position for much
longer, but can't yet make a reasonable guess about what will take
its place.

Someday I will discuss what neuroscientists have thought about 
identity, too. As for both memory and identity, I would definitely
say that it helps to learn about what others have thought on those
subjects, if only because doing so will help you avoid mistakes
which causes them to adjust their theories. To theorize about such
things without doing some reading beforehand risks that you come up
with a theory that those who have been at it longer than you have
ALREADY found to have many faults, enough to exclude it....and to
be more general, the way to come up with an original idea isn't
to ignore what others have said but to pay attention to it and 
work out a new way to get around its problems.

		Best wishes and long long life for all,

			Thomas Donaldson

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