From: Lee Corbin <[EMAIL PROTECTED]>
Godfrey writes
> As much as I sympathize with your call for preservation of naive
> realism
[LC]
Good heavens! How many times must it be said? What is going on
with people? There is a *clear* definition of "naive realism".
Try the almost always extremely reliable wikipedia:
http://en.wikipedia.org/wiki/Naive_realism
If one is very clear that information about events outside
the skin is conveyed to one's brain by layers of intermediate
processes, (usually beginning with emissions of photons or by
vibrations imparted to air), then you are *not* a naive realist.
[GK]
My, are prickly today!!! In this is when I was still sympathizing with
you! (;-)
[LC]
Since this has come up so many times before---and not just on this
list---I'm really starting to wonder what the explanation is. You
can even find links on the web that confuse realism and naive
realism.
The acid test of what to call something is "do the adherents of
the view themselves use the term?". Then, in cases like this,
we see it for what it is: name calling.
[GK]
Hold on! I don't believe I have even called you a "naive realist"!
> and agree entirely with your opinion on the demerits
> of introspection. I have to take issue with half of
> what you say below:
[LC]
Of course. Anyone who understands and believes in
PCR always invites criticism, as least as much as
he has time for.
> > I'm not too sure what you mean by "to embed".
> > If we are seeking to *explain*---if that is
> > what you mean---then we cannot explain QM by
> > classical physics, but we *can* explain classical
> > physics by QM. (I take our primary activity to
> > be---and the activity I'm most interesting in
> > participating in---*explaining*.)
>
> Yes we cannot explain QM by classical physics
> but NEITHER can we explain from QM the classical
> world we know and love with its well defined and
> assigned elements of (naive) physical reality
> that you so much cherish, I am afraid! If we did
> there would not be no Measurement Problem, no spooky
> long-distance correlations, no zombie Schrodinger
> Cat's around to haunt us...
Quantum mechanics' greatest successes have included
explanations for what you cite. That is why QM is
accepted.
[GK]
My point is that it does NOT include explanations for
any of the items I cite and that is why I cite them
and that is why they are called "problems".
From Bruno's message I take it that you subscribe to the
Everett Interpretation which indeed "avoids" some of these
problems but has some more of its own and
surely does a number on your "naive reality"!
What is it then: many worlds or one?
[LC]
But you seem to be saying that the *correct* results
of classical physics cannot be obtained from QM. Surely
you don't mean that. Of course they can! If they could
not, then they'd be wrong!
True, classical physics *cannot* explain many phenomena,
such as why black bodies radiate the way that they do,
and this bothered 19th century physicist a great deal.
Planck was *forced* to come up with the concept of the
quantum, if he was to be able to explain.
[GK]
No, I am not saying that QM does not reproduce much of
the classical results given the appropriate limits. Indeed it can
and it, furthermore, predicts and explains a number of
macroscopic (thus part of the world of direct experience)
phenomena that Classical Physics does not.
What I am saying above (and this is the clincher of the EPR argument
as is that of the Everett interpretation) is that QM does not provide
you with a picture of a reality where objects naively have their
well defined properties associated with assignable elements
of physical reality.
> You see, amplitudes don't just add! They also multiply
> and square!
[LC]
Why, of course. Just how innocent of QM do you suppose
that I am? I invented the phrase "at the basis of things
are amplitudes that add" after a thorough study of Feynman's
volume 3. The multiplication obtains---at the very beginning
---simply from concatenating paths: you multiply amplitudes
to get a total amplitude for one path.
[GK]
If that sentence is any measure of your "guilt" that you will
be doing "quantum time", Lee (:-) What you want to say
is "at the basis of QM there are amplitudes that add, multiply
and square". Notice the absence of "things"! It is the
"things" that ain't there!!!
[LC]
Your point about the squared modulus is well taken. Just why
*probabilities* emerge from squared amplitudes, I couldn't
tell you. I'm not sure that anyone knows---as I recall, many
this is related to the basis problem of the MWI (though
Deutsch and others say that decoherence takes care of
everything, though).
Lee
[GK]
Wouldn't that be nice! Unfortunately they are wrong about
that. Decoherence is promising but still in need of major
patching. Check out the paper by Bassi and Ghiraridi:
http://arXiv.org/abs/quant-ph/9912031
There is some newer work on this by Adrian Kent but I
don't have the reference handy. As to why the amplitudes
square to give probabilities I agree with you that no one knows!
Regards,
Godfrey
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