From stapp@thsrv.lbl.gov Mon Sep 30 09:18:57 2002
Date: Mon, 30 Sep 2002 09:16:10 -0700 (PDT)
From: stapp@thsrv.lbl.gov
Reply-To: hpstapp@lbl.gov
To: Mszlazak@aol.com
Cc: hpstapp@lbl.gov
Subject: Re: QM question: Can Bohmian mechanics be made to work with
strictly a classical
On Mon, 23 Sep 2002 Mszlazak@aol.com wrote:
> Hello Dr. Stapp.
>
> Can Bohemian mechanics be made to work as an interpretation of Quantum
> phenomena as a strictly classical materialistic interpretation. If not why
> not and if so then why has this version not been widely accepted?
>
> Thanks. Mark Szlazak.
>
Dear Mark,
I just returned from a small conference attended by Basil Hiley, among
a pestigious group of 17. An Oxford Philosopher of Science, S. Saunders,
asserted strongly a point that I have often made, namely that the theory
has never been extended to the relativistic case involving particle
creation. Hiley did not disagree, but I believe admitted that this was
indeed the case. So that is one reason why the theory as it stands is
inadequate.
I have also a second criticism. An adequate theory must make predictions
about empirical results of experiments. The way Bohm achieved this was to
link his theory to Copenhagen ideas, and show that his theory gave the
same results as Copenhagen. But the Copenhagen interpretation depends
critically upon what von Neumann later called Process I. This is an
intervention that is in principle not derivable from the unitary
evolution, but requires an outside choice of which experimental
set up is to be selected from a (continuously) infinite set of
alternative possibilities. Given that some good apparatus is in place
Bohm computed the probabilities in his theory by showing that the
relative probabilities of his Bohm trajectory entering the various
channels associated with the alternative possible outcomes of the
experiment were just the same as the Copenhagen prediction that
the corresponding outcome would be "observed." So if one associates
the Bohm trajectory with human experiences then one achieves concordance
between Bohm and Bohr.
But Process I is an intervention that Bohmian mechanics lacks. Hence
that theory by itself gives no predictions!
To see the problem in more detail suppose we have an initial state of
the universe that has been evolving since the big bang with no Process I
interventions. Every physical object will be smeared out over a continuum
of locations. Let's focus on the location of a Geiger Counter. The single
location selected by a Process I intervention will be surrounded by a
continuum of slightly displaced locations. For each of these possible
locations there will be some probability that the Bohmian trajectory
passes through the detection region. But there is a continuum of possible
locations. So the total probability will be infinite. This is precisely
the difficulty that the founders of quantum theory, and von Neumann,
resolved by bringing in the Process I intervention, which picks out
from the continuum of possible basis states generated by the unitary
evolution (Process II) some particular basis. Without this Process I
intervention the theory gives no well-defined predictions: the unitary
evolution by itself, in conjunction with a Bohm trajectory, does not
yield well-defined predictions pertaining to empirical/experiential
results. Process I interventions (or some other extra processes) are
needed. The founders and von Neumann did not introduce this Process I
intervention with no good reason.
This same criticism applies to the Everett-type theories.
Regards,
Henry
From stapp@thsrv.lbl.gov Wed Oct 2 09:10:26 2002
Date: Wed, 2 Oct 2002 09:01:42 -0700 (PDT)
From: stapp@thsrv.lbl.gov
Reply-To: hpstapp@lbl.gov
To: Mszlazak@aol.com
Subject: Re: Consciousness and 2nd law of thermodynamics
On Wed, 2 Oct 2002 Mszlazak@aol.com wrote:
> Hello Dr. Stapp.
>
> I've heard lots of people argue that consciousness can't be causal because it
> "violates the 2nd law of thermodynamics." What is the status of this second
> law, has it changed, and why would this argument not be valid with regard to
> the consciousness having a causal role? Or would it?
>
> Thanks AGAIN :-)
>
> Mark Szlazak.
>
I have a whole chapter of my (short) book on von Neumann's reconciliation
of consciousness with the second law. The point is that von Neumann
uses only Process I, not Process III, and Process I is compatible
with the second law.