Re: Quantum spookiness in the brain?

In message <ftjgn9$pd1$3@xxxxxxxxxxxxxxxxx>, Paul J Gans <gans@xxxxxxxxx> writes
Vend <vend82@xxxxxxxxxxx> wrote:
On 9 Apr, 21:27, r norman <r_s_norman@xxxxxxxxxxxx> wrote:
On Wed, 9 Apr 2008 12:08:26 -0700 (PDT), Vend <ven...@xxxxxxxxxxx>
wrote:



>On 9 Apr, 19:51, r norman <r_s_norman@xxxxxxxxxxxx> wrote:
>> On Wed, 9 Apr 2008 16:30:42 +0000 (UTC), Paul J Gans <g...@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.

>This assumes that the physical laws are computable, or at least can be
>approximated by computable functions to any arbitrary level of
>precision.
>This is exactly the assumption that Penrose and Hameroff challenge.

>All known fundamental physical phenomena seem to be described by
>(approximately) computable laws, with the only exception of quantum
>wavefunction collapse, which seems to be probabilistic.
>Many interpretations of quantum mechanics have been formulated to try
>to address this oddness. Some just accept it as it is while others
>suggest that it might be actually a deterministic chaotic phenomenon.

>Penrose and Hameroff instead suggest an interpretation where quantum
>wavefunction collapse is governed by a (still unknown) uncomputable
>physical law.

>Their rationale for doing so is that they have convinced themselves
>that certain aspects of human behavior (like mathematical intuition)
>aren't compatible with a computable (and possibly probabilistic)
>physics, thus they have cringed on the only not completely explained
>fundamental phenomenon.

>However, their argument for the non-computability of human behavior is
>flawed (IMHO and in the opinion of most experts), making their
>proposed interpretation unparsimonious.

I remember a time when Penrose argued that quantum gravity must be the
factor behind consciousness since it was the only part of physics left
unexplained.

Right, he thinks that when quantum gravity is explained, it will
explanation for quantum wavefunction collapse and provide the
mechanism to understand human consciousness.
If I remember correctly, his schema for explanation is:
- Particles with mass distort space-time.
- Particle quantum states can be in superposition.
- A superposition of states of a massive particle causes a
superposition states of space-time.
- When the superposed states of space-time become too much different
(respect to a threshold depending perhaps on h and c), the universe
forces the superposition to collapse towards one state of space-time
and hence one state of massive particles (and entangled mass-less
particles).

Hmmm.

I think it can be demonstrated that quantum wave function
collapse is a product of human-environment interaction.

Consider the Schrodinger's Cat Modified: We have a container
with the usual cat and random apparatus. One one side of the
container we have the usual wise observers who create a state
function for the cat that is a supersition of two states with
appropriate normalization constants.

On the other side, and hidden from the first observers by
a curtain or what have you, is another set of observers. Their
side of the container has a glass wall. Their state function
for the cat never collapses at all.

If the cat dies, their wave function does exhibit a state transition
from phi_{living} to phi_{dead}. This transition is akin to
an electronic transition.

What I am claiming, and think I have shown an instance of, is that
the wave function represents *our* knowlege of the system at any
time t. It is always a composite function to some extent, but the
more we know, the fewer terms are included.

Comments?


I subscribe to the pragmatic interpretation ("shut up and calculate") of Quantum Mechanics - in other words for all the problems as to what QM means, we can ignore them to the degree that QM still remains a startingly effective theory for predicting the behaviour of the world.

As I understand the matter it is not correct to say that the wave function represents out knowledge of the system. Experiments with Bell's Inequality exclude, if I recall correctly, a local hidden-variable theory - meaning that we either have to give up determinacy or locality.

I think that your invocation of Schrodinger's Cat is a red herring. Schrodinger's Cat is a thought experiment that raises the question of why behaviour is classical at macroscopic scales. It doesn't not allow us to infer that the cat is neither alive or dead.

Your argument is tantamount to a claim that the wave function of a system can be different for different observers. For an experimental test of this I suggest the following - a linear accelerator in which anti-protons are slammed into protons, and two particle detects at successive points downstream of the path of the resulting particles, each with a separate observation team. Let the antiproton energy be tuned to produce Y-mesons. These can decay in several ways - e.g. into an electron-positron pair, or a muon-anti-muon pair.

If you are correct then what the people observing the second detector doesn't depend on what the people observing the first detector saw first. Assume that for the sake of argument that each of the stated decay paths occurs at a 50% rate. You predict that the second team will observe a positron 50% of the time, regardless of whether the first team observed a position or an anti-muon. I think that you will find that this prediction is not borne out by experiment.
--
alias Ernest Major

.

Relevant Pages

  • Re: Quantum spookiness in the brain?
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  • Re: Quantum spookiness in the brain?
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  • Re: Quantum spookiness in the brain?
    ... identical brains will think absolutely the same thoughts and make ... have absolutely identical brains because of quantum uncertainty. ... wavefunction collapse, ... their wave function does exhibit a state transition ...
    (talk.origins)
  • Re: Quantum spookiness in the brain?
    ... identical brains will think absolutely the same thoughts and make ... have absolutely identical brains because of quantum uncertainty. ... Consider the Schrodinger's Cat Modified: ... and hidden from the first observers by ...
    (talk.origins)