Re: Does the state-vector collapse?

From: David Blenkinsop (blenl@sk.sympatico.ca)
Date: Tue Sep 19 2000 - 18:15:57 MDT


Yesterday, scerir wrote:

>
>
>
> In a parallel paper (38 pages)
> http://arxiv.org/abs/quant-ph/0009062
> Henry P. Stapp is trying to explain non-locality by means of his
> quantum-mind-brain model.
> <Orthodox Copenhagen quantum theory renounces the quest to understand
> the reality in which we are imbedded, and settles for practical
> rules that describe connections between our observations. However,
> an examination of certain nonlocal features of quantum theory suggests
> that the perceived need for this renunciation was due to the
> uncritical importation from classical physics of a crippling
> metaphysical prejudice, and that rejection of that prejudice
> opens the way to a dynamical theory of the interaction between
> mind and brain that has significant explanatory power.>

Sounds generally interesting, however, I find I have a skeptical
reaction to the idea of "dynamical interaction between mind and brain"
as explaining anything more than many of the standard ideas relating to
quantum theory. For instance, the Copenhagen assumption of state-vector
collapse already depends on the assumption of a special, dynamic,
interaction between measuring devices and the quantum world! Also, if we
wish to question whether the collapse happens at all, isn't the Many
Worlds idea, supported by Deutsch and others, very much the standard
here? Sometimes Many Worlds can even be *hinted* at in discussions where
it isn't actually mentioned explicitly, as in the following quotation
from a very recent message on the sci.physics.research newsgroup (John
Baez was the writer of the message that I'm quoting from):

"When the position of an object affects the stuff in its environment,
putting the object in a superposition of position states will soon
cause its environment to be in a superposition of states as well.
If the environment includes *us*, we will wind up in a superposition
of states where we see the object in various definite positions. This
means we'll see the object in some (random) position, rather than seeing
the interference effects normally associated with superpositions of
position states."

Now this sort of statement surely represents some kind of metaphysically
wild scenario! If I wind up existing in a "superposition of states",
this is just the same as saying that there are many different copies of
me, existing in separate parallel worlds, the worlds having branched off
from one another at some point in the flow of time. So I'll never be
aware of this general, "environmental" superposition, and *that's* what
effectively pins the observed object to one location, the object's
timeline having split in tandem with my own, you see.

To the extent that Many Worlds explains what superpositions are all
about, better than more ordinary, Copenhagen style explanations, I
suppose we have to consider the possibility that *all* possible world
histories are equally real? Does this make any difference to our
scientific outlook on the world, or do we just discount Many Worlds as
one more grand uncertainty, as in "gee, don't know if all those
alternate histories are real, or not?" Even just as a matter of
explaining to someone what is implied or suggested by basic science
these days, this has some importance, right? For the moment I'm saying
that the agnostic position, "don't know if alternate worlds exist or
they don't" is the best I can do. Will there ever be a way to do better?

David Blenkinsop <blenl@sk.sympatico.ca>



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