From: John K Clark (johnkc@well.com)
Date: Mon Jul 20 1998 - 13:48:29 MDT
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"Jonathan Colvin" <jcolvin@ican.net> On Mon, 20 Jul 1998 Wrote:
>It [Uploading] seems to rest on a very narrow model of consciousness
>that regards neurons as discrete computational elements that can be
>simulated.
Unless a neuron has a soul it can be simulated. One neuron sees another
neuron as a black box, it doesn't matter how it does what it does as long as
it gets the job done.
>I think this model seriously de-emphasizes the chemical elements of
>consciousness...the enormously complicated stew of neurochemicals
>the washes thorugh our brains, [ ...] I am of the opinion that much
>of consciousness is dependent on very complicated chemistry. You
>might say I am of the "wet" school of consciousness. And how can
>you upload norepinephrine?
I don't see the slightest reason why norepinephrine or any other
neurotransmitter would be especially difficult to simulate, because chemical
messengers are not a sign of sophisticated design on nature's part, rather
it's an example of Evolution's bungling. If you need to inhibit a nearby
neuron there are better ways of sending that signal then launching a GABA
molecule like a message in a bottle thrown into the sea and waiting ages for
it to diffuse to it's random target.
I'm not interested in chemicals only the information they contain, I want the
information to get transmitted from cell to cell by best method and few would
send smoke signals if they had a fiber optic cable. The information content
in each molecular message must be tiny, just a few bits because only about 60
neurotransmitters such as acetylcholine, norepinephrine and GABA are known,
even if the true number is 100 times greater (or a million times for that
matter) the information content of each signal must be minute. Also, for the
long range stuff, exactly which neuron receives the signal can not be
specified because it relies on a random process, diffusion. The fact that
it's slow as molasses in February does not add to
its charm.
If your job is delivering packages and all the packages are very small and
your boss doesn't care who you give them to as long as it's on the correct
continent and you have until the next ice age to get the work done, then you
don't have a very difficult profession. I see no reason why simulating that
anachronism would present the slightest difficulty. Artificial neurons could
be made to release neurotransmitters as inefficiently as natural ones if
anybody really wanted to, but it would be pointless when there are much
faster ways.
Electronics is inherently fast because its electrical signals are sent by
fast light electrons. The brain also uses some electrical signals, but it
doesn't use electrons, it uses ions to send signals, the most important are
chlorine and potassium. A chlorine ion is 65 thousand times as heavy as an
electron, a potassium ion is even heavier, if you want to talk about gap
junctions, the ions they use are millions of times more massive than
electrons. There is no way to get around it, according to the fundamental laws
of physics, something that has a large mass will be slow, very, very, slow.
The great strength biology has over present day electronics is in the ability
of one neuron to make thousands of connections of various strengths with
other neurons. However, I see absolutely nothing in the fundamental laws of
physics that prevents nano machines from doing the same thing, or better and
MUCH faster.
John K Clark johnkc@well.com
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