RE: Explaining QM to the layperson

[Leigh Palmer <palmer@sfu.ca>]

"....no one knows how it can be that way, it just is."

Feynman didn't refer to the Copenhagen interpretation, he referred to the
evident fact that QM has predictive power when applied algorithmically
by doing mathematics. Outside that context he made no claims.

I'm a fan of the Einsteinian (or statistical) interpretation of the QM.
It is minimal and makes no claims which are in principle unfalsifiable.

> I agree that the Schrodingers Cat gedanken experiment could have been used
> to illustrate the seeming absurdity of the Copenhagen interpretation of QM.

I don't understand "could have". Schrodinger's cat lays it on the line.
Either you are an objective realist or you are not; it's that simple.
What you must recognize is that some belief structure is necessary to the
interpretation of Nature. I am a realist; I believe in objective realism
without reservation. Schrodinger's cat in its mixed state is anathema in
my belief structure, but it is a logical interpretation in the Copenhagen
faith. I reject the Copenhagen faith.

> However it could also serve as a means to attempt to bring the odd
> properties of the QM world into a realm closer to our experience so that
> we might appreciate more the differences between the micro and macro worlds.
> In this sense it is in the spirit of Mr. Tompkins adventures, is it not?

Much of Mr. Tompkins is fairy tale. Charming in its time, and redolent
with concretizations of Copenhagen ideas in its QM parts, Mr. Tomkins
is now only suitable for children still enchanted by fairy tales. We
have Feynman's path integral formulation with its attendant
interpretation laid out in his book "QED, the strange theory of light
and matter". It is a worthy successor to Gamow's book (the atom one)
for nonmathematically inclined adults.

> As far as providing the students with alternatives, I did mention
> Everett's Many World's Interpretation.

Appropriate. That is yet another fairy tale, baren of capability to
predict testable consequences which would distinguish it from other
interpretations.

> Amazingly, they were significantly more comfortable with this concept.
> Probably due to the fact that so much media SciFi plays on this idea.

The best science friction is merely fairy tales for older children. No
one takes science friction seriously as an interpretation of Nature.

> I did point out to them that if they recalled our discussion of the
> Scientific Method, that this theory was untenable due to it's
> untestability. The only truly different interpretation that I can
> think of is Bohm's Causal Interpretation which I understand to be most
> closely related to deBroglie's pilot wave theory.

I believe the bottom line is that one cannot usefully interpret
microscopic phenomena without recourse to mathematics. Some aspects of
the Copenhagen interpretation are useful and not terribly misleading
(e.g. tunneling) and some are absurd. It seems to me that the absurd
aspects are pushed in all "popularizations". Schrodinger's cat is
presented as if it were a real possibility in an ideal case. The best
one can do is to present results and describe the symmetries that
result and the surprising outcomes, predicted by the mathematics, and
observed in Nature, which are not consistent with classical physics.
Going beyond this is fiction. Fiction itself is not bad; the fictions
of physics can be quite amusing as Schrodinger's cat or other nonsense
amply instantiates. Fiction is not science, however, and unless you
clearly label the fiction your naive students will think you are
teaching them science; that is the danger.

Teaching the substance of QM to students incapable of appreciating the
mathematics is like teaching music appreciation to students who have
been profoundly deaf from birth. Only a negligible fraction of them
could benefit. Ask yourself the question "Could I be spending this
brief time I have with these students teaching them something about
Nature that they will be able to appreciate more than the QM?" If the
answer is "Yes" then do it. You must also let them know that you are
not teaching them QM because you don't understand it yourself in other
than mathematical terms, and cite Feynman in support of your position.
Tell them about the phenomena of atomic physics. Introduce them to the
Bohr atom. Tell them that *no* physicist believes in the literal truth
of this model today, but that it does have powerful predictive power,
and use *that* as an example of how mathematical theories arise. Don't
press it farther by presenting fantasies more difficult to understand
- and believe!

Leigh