From: daryl@oracorp.com (Daryl McCullough)
Subject: Re: What does quantum have to do with it?
Organization: ORA Corporation
Date: Thu, 21 Jan 1993 14:53:14 GMT

martel@marvin.mr.sintef.no (Paulo Martel) writes:

>sichase@csa1.lbl.gov (SCOTT I CHASE) writes:
>>There are many fascinating puzzles in science that are enough to keep
>>each of us busy for many lifetimes, based upon interesting, or puzzling,
>>experimental evidence, without creating new ones out of thin air.  If you
>>want to speculate wildly, there are no grounds for scientific discussion,
>>because your claims or hypotheses are not grounded in any experimental
>>evidence, so there is no experiment to do, which has not been done,
>>to test your hypothesis.

Scott of course is giving the standard line, that science is about
prediction, and any discussion that does not have empirical
consequences is therefore "wild speculation". I would prefer to use
the word "philosophy". I think that Scott has somewhere lost touch of
the purpose of science: besides the modern purpose of allowing us to
build bigger and better gadgets, there is the much more ancient
purpose of trying to understand the universe we live in. Experiment
should certainly play an important role in testing our understanding,
but it isn't an end in itself. And there are other tests of our
understanding: the coherence, consistency, and perhaps elegance of
our theories.

>>For example, you, or perhaps some previous poster, speculated wildly that
>>there exists some underlying physics which would "explain" quantum mechanics
>>and it's apparent intrinsic randomness.  OK, how do you want to test this?
>
>>What about the body of evidence, apparently unknown to the original 
>>poster, which demonstrates under a broad set of conditions that this is 
>>not the fact?  How are you going to frame this discussion such that
>>we can talk reasonably about it, or even better, do an experiment?

Physicists seem to use Bell's theorem as a way to shut up people up
who talk about interpretations of quantum mechanics. I don't think
that Bell thought of his work along the lines of ending all discussion
of interpretations and alternate theories. It simply placed
constraints on what an alternate theory could be like and still agree
substantially with the predictions of quantum mechanics.

>>Heisenberg and Schroedinger worked many decades ago, long before the 
>>modern work of Bell, et al, on these issues.  Furthermore, they were
>>very unsure about the future of quantum mechanics because it was new, 
>>relatively untested, and unexplored. Today, it's a different world.
>>A new generation of scientists has grown up with quantum mechanics, and
>>it's implications. They are much more well understood than in Heisenberg's
>>day. I am not the only physicist who is comfortable with quantum 
>>mechanics.

I would replace the word "comfortable" with "complacent". I would say
that most physicists are complacent about quantum mechanics. However,
I wouldn't say that most physicists understand quantum mechanics very
well. If you ask most physicists to try to explain the basic concepts
of quantum mechanics, you will find that their understanding is
incoherent and even inconsistent. They have no way of describing the
laws of quantum mechanics without reference to one of the following:
observer, observables, observation, measurement, measuring device.
However, when pressed, they usually will say that there is nothing
special about a measuring device or an observer, they are quantum
systems, too, although complex ones.

That is one thing I find incoherent in quantum mechanics; it
simultaneously requires that observers be given special status in the
theory and denies that they have such a special status. Another source
of incoherence is the nature of the wave function. Physicists often
deny that the wave function is an objective physical quantity, and
also will deny that anything *other* than the wave function is an
objective physical quantity. They will say that nothing is real except
observation, and then say that observation is simply a special case of
a quantum mechanical interaction.

The bottom line for physicists is of course prediction, and in spite
of the incoherent mess that quantum theory is, one can identify a
solid enough core to make uncannily accurate predictions. That's
enough for some people, but not for everyone.

Daryl McCullough
ORA Corp.
Ithaca, NY