Godfrey writes

> As much as I sympathise with your call for preservation of naive 
> realism

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.

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.

> and agree entirely with your opinion on the demerits
> of introspection. I have to take issue with half of
> what you say below:

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.

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.

> You see, amplitudes don't just add! They also multiply
> and square!

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.

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

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