Re: copy method important?

From: Hal Finney <>
Date: Sat, 18 Jun 2005 15:52:37 -0700 (PDT)

Norman Samish writes:
> Isn't it possible that decision processes of the brain, hence
> consciousness, DOES depend critically on quantum states?

Yes, it's possible. There is a school of thought which advances this
position. Penrose, Hamerhoff are a couple of the names, off the top
of my head. There is an extensive literature on the subject to which you
could find some entries via Google. I just did so and found archives
of a mailing list called QUANTUM-MIND which is all about this subject.

Nevertheless I think it is safe to say that the opposite opinion
is more widespread, that the mind does not depend critically on any
quantum property. One of the main reasons is that quantum coherence
is very difficult to maintain outside of carefully prepared laboratory
conditions. Another point is that our models of neurons do not require
quantum behavior, yet computer simulations suggest that they can learn
patterns and respond in meaningful ways similar to actual neural tissue.
Of course we are far from being able to simulate anything at the level
of consciousness, but so far there is nothing observable about neural
behavior that suggests nonclassical effects.

> My understanding of the workings of the brain is that my action, whether
> thought or deed, is determined by whether or not certain neurons fire. This
> depends on many other neurons. So the brain can be in a state of delicate
> balance, where it could be impossible to predict whether or not the neuron
> fires.
> We all have to make decisions where the pluses apparently equal the
> minuses. It would take very little to tip the balance one way or the other.
> Perhaps, at the deepest level, the route we take depends on whether an
> electron has left or right polarization, or some other quantum property -
> which we agree can't be measured.

I think it is doubtful that neurons often get into a condition where
they are so delicately balanced that a single electron could make a
difference. There are a lot of electrons in a neuron! But even if it
did happen, it wouldn't mean that the neuron *depends* on this effect.
A simulation of a brain that was non-quantum might not behave 100% the
same as the real brain being modelled, but it would probably work ok.
By their nature, brains need to be robust and immune to disturbances.
Neurons are constantly dying, their internals assaulted by changes in
blood chemistry, but the brain keeps chugging away. It's not exactly
a delicate flower. Again, this is exactly the opposite of the quantum
behavior we observe in the lab, which is extremely sensitive and gets
messed up if you look at it funny.

> If this is true, then perhaps Free Will (or at least behavior that is,
> in principle, unpredictable) does exist.

Right, well, for many people, being at the mercy of unpredictable and
uncontrollable randomness may be free but it's hardly willful.

Hal Finney
Received on Sat Jun 18 2005 - 19:48:46 PDT

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