X-Message-Number: 3778
Date: Wed, 1 Feb 1995 21:40:38 -0800
From: John K Clark <>
Subject: SCI.CRYONICS Uploading


"Steven B. Harris" <> Wrote:

	     >I cannot see what exchange forces (Pauli forces) have to do
	     >with anything 
I don't think exchange forces have anything to do with
consciousness, I only mentioned them to demonstrate that quantum
particles have no individuality, but as long as were on this
tangent ;  Pauli's exclusion principle is very important ,it's
the basis of the periodic table, but it's only one example of
exchange forces .
	    >such forces operate only between "identical" members of one
	    >class of  partic-les (fermions), and but not "identical        
	    >members" of the other class. [...]   condensation into
	    >the same quantum state in the absence of exchange  forces
	    >between bosons ...
Exchange Forces do operate between bosons but unlike the Pauli
exclusion principle that acts only on fermions and is repulsive,
on bosons exchange forces are  weak and a force of attraction
not repulsion. Exchange forces are what causes Bose-Einstein
condensation that you were referring to. 
We must use The Identity Of Indiscernibles to derive the fact
that there are indeed two classes of particles. Experimentally
we can't measure the quantum wave function  F(x) of a particle
we can only measure the intensity of the wave function [F(x)]^2
because that's probability and probability we can measure . 
P(x) =[F(x)]^2 is the probability of finding two particles x
distance apart. Now let's exchange the position of the
particles, the distance between them was x1 - x2 = x is now x2 -
x1 = -x . The Identity Of Indiscernibles tells us that because
the two particles are the same no measurable change has been
made , no change in probability ,so P(x) = P(-x) . From this we
see that  [ F(x) ]^2 = [ F(-x)]^2 so the Quantum wave function
can be an even function [ F(x) = +F(-x)  ] or an odd function 
[F(x) = -F(-x) ] , remember (-1)^2 = (+1)^2 =1.

Both solutions have physical significance, particles with
integer spin , bosons, have even wave functions, particles with
half integer spin , fermions, have odd wave functions . If we
put two fermions like electrons in the same place then the
distance between them x is zero and because they must follow odd
wave functions , F(0)  = -F(0) but the only number that is it's
own negative is zero so  F(0)  =0 . What this means is that the
wave function goes to zero and  [F(x)]^2 goes to zero , thus the
probability of finding two electrons in the same spot is zero
and that is The Pauli Exclusion Principle.

What all this has to do with survivability, immortality or
uploading is left as an exercise for the reader.

	     >being quantum-identical in quantum mechanics does *not*
	     >guarantee identical behavior. 
Quite true, quantum mechanics is after all a non deterministic theory. 
	     > two identical brains become quantum non-identical with great
That would be true even without quantum mechanics. Nobody has
ever proven that quantum effects change the way the brain
functions at all  but it probably has a subtle, negative, effect
by introducing a little randomness. There's not a shred of doubt
that the environment ( sense input, drugs, a blow to the head)
can alter the operation of the brain and the effect can be huge.
Drinking a cup of coffee will change you more than quantum non
deterministic events ever will.
	   > Please note that this is the same problem that all of us are
	   >faced with every single day. 
Absolutely true. It doesn't bother us now so I see no reason it
will bother us in the future. I could change my mind about that
but if I do it will almost certainly be because of computation
or changes in my environment and not because of quantum effects
in my brain .
				     John K Clark        

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