Re: Quantum spookiness in the brain?

On Wed, 9 Apr 2008 16:30:42 +0000 (UTC), Paul J Gans <gans@xxxxxxxxx>
wrote:

<snip>

I believe that Penrose was dealing with what I will call
the "mechanistic view" of the mind. In that view two absolutely
identical brains will think absolutely the same thoughts and make
absolutely the same decisions.

Folks who think this are basically saying that there can be no
free will since thoughts are then totally dependent on the physical
details of the brain that thinks them.

For many, the only way out of this is to posit a supernatural
something that would allow absolutely identical brains to think
different thoughts.

Penrose, I believe, was pointing out that it is impossible to
have absolutely identical brains because of quantum uncertainty.

The rest of his thinking then took off from this point of departure.
And I agree that the rest of his thinking may be just so much
poop, but the problem of identical brains is a real one and I believe
it is solved by quantum uncertanty.

The notion that identical brains must think alike and act alike is,
indeed, logically equivalent to the notion that, given the details of
one brain, one can then compute presumably the future of what it will
do. That is essentially the Newtonian universe view of the world, a
world in which there can be no free will. My definition of the
'details' which must be specified is exactly the same list of
'details' in which the duplicate brain must match the original.

But let us suppose that we do live in a Newtonian universe free from
any uncertain or quantum activity whatsoever. We know that chaotic
mathematical systems exist in which the slightest error in initial
conditions completely precludes prediction the future of the system.
Those systems are not at all rare; even 'simple' gravitational systems
of point masses are chaotic. And it is not enough to specify the
particles that make up the brain. Brownian motion in the environment
produces collisions in the brain that can influence its future so that
the position and momentum of every particle that could ever interact
with the brain or that could interact with a particle that could
interact with the brain or that could interact with a particle that
could interact with another particle that could.... must also be
computed.

We also know that any reasonably complex system cannot be computed
analytically; the equations must be solved numerically to predict the
future. Computations are limited in precision. We can use double
precision arithmetic quadruple precision or whatever finite length
precision we choose and still our numerical computations are limited
by finite word length and finite step size in the solution of the
partial differential equations of physics. Combine the inaccuracy of
computation with the problem of prediction in chaotic systems and you
find that it simply is not possible to predict the future for any
macroscopic system (Avogadro's number of particles) no matter how
large and fast a computer we may choose. The computer is still finite
and the computational problem so immense that the computation cannot
occur in real time.

The problem of identical brains is an interesting thought problem for
a conceptual universe but is absolutely no problem at all in a real
universe with real organisms producing real behavior.

.

Relevant Pages

  • Re: Quantum spookiness in the brain?
    ... identical brains will think absolutely the same thoughts and make ... details of the brain that thinks them. ... the position and momentum of every particle that could ever interact ...
    (talk.origins)
  • Re: Quantum spookiness in the brain?
    ... identical brains will think absolutely the same thoughts and make ... details of the brain that thinks them. ... the position and momentum of every particle that could ever interact ...
    (talk.origins)
  • Re: Quantum spookiness in the brain?
    ... identical brains will think absolutely the same thoughts and make ... details of the brain that thinks them. ... the position and momentum of every particle that could ever interact ...
    (talk.origins)
  • Re: Quantum spookiness in the brain?
    ... identical brains will think absolutely the same thoughts and make ... details of the brain that thinks them. ... the position and momentum of every particle that could ever interact ...
    (talk.origins)
  • Re: Quantum spookiness in the brain?
    ... identical brains will think absolutely the same thoughts and make ... details of the brain that thinks them. ... the position and momentum of every particle that could ever interact ...
    (talk.origins)