Re: "Naive Realism" and QM

From: <>
Date: Thu, 18 Aug 2005 10:54:28 -0400

 From: Lee Corbin <>

 Godfrey writes

> As much as I sympathize 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:

 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.

  My, are prickly today!!! In this is when I was still sympathizing with
you! (;-)

 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

 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.

 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:

 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

 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?

 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.

 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!

 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.

 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!!!

 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).


 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:

 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!


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Received on Thu Aug 18 2005 - 10:58:59 PDT

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