From: Hal Finney (hal@finney.org)
Date: Thu Mar 28 2002 - 01:38:47 MST
Dan forwards:
> See http://home.mmcable.com/cogans/chris/Indeterminism_problem.htm
>
> I know this subject has been beaten to death, ressurected and beaten
> back to death again, here and elsewhere numerous times, but since
> quantum physics is again under discussion here, though more from an
> applications perspective, I thought some of you might find this article
> of interest.
I didn't think this article was very clear or well written. If you're
going to try to counter a particular argument, you need to set the
argument out clearly, or at least provide a reference to such a statement.
This article seems to assume that people know what the argument is,
and it alludes to it only vaguely and sarcastically.
Indeterminism is a fundamental mathematical *assumption* of the Copenhagen
interpretation. There are two dynamical processes in quantum systems
under this interpretation, which von Neumann called Type I and Type
II. Type II processes are what happens when no measurements occur.
The systems evolve continuously and deterministically according to
the Hamiltonian function, which relates to the energy. This part is
closely analogous to classical, pre-quantum formulations of dynamics.
Type I processes occur when a measurement happens. At that point the
quantum state gets projected onto one of the basis vectors associated
with that kind of measurement. The projection is probabilistic and
nondeterministic, and the probabilities depend on the amplitudes of the
wave function.
That's Copenhagenism in a nutshell. If you accept it as the starting
point, as this article claims to do, then there is no question but that
empirical indeterminism is a fundamental part of the theory.
But the article seems to be trying to oppose some argument based on an
EPR type experiment with coupled photons which are allowed to separate.
It's not clear what exactly the argument is, so it is hard to say just
how successful the article refutes it.
Hal
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