Here's a parable: True fact: to make french fries, you need
a pot of hot oil. Another true fact: some people like to
put catsup on their french fries, although other people find
catsup unnecessary, and some people consider it an abomination.
Now ... suppose somebody sees a pot of hot oil and announces
that he has thereby proved the existence of catsup. That is
at least two fallacies removed from rational thinking.
Interpretation: True fact: in order to do quantum mechanics,
you need waves. Another true fact: some people like to augment
the laws of quantum mechanics with stories about multiple
worlds, although other people find this unnecessary, and
some people consider it an abomination. Now ... suppose
somebody sees evidence of waves and announces that he has
thereby proved the existence of multiple worlds. That is
at least two fallacies removed from rational thinking.
To say the same thing in more precise, technical terms:
The MWI (Many-Worlds Interpretation) was intended to help
people understand certain non-classical non-intuitive
aspects of quantum mechanics ... aspects that are _not_
demonstrated by observation of the two-slit interference
pattern. Again we conclude that using the interference
pattern by itself to "prove" the MWI is grossly fallacious.
Tangent, for those who want the next level of technical
detail: The QM notion that events can be correlated even
if they are separated by a spacelike interval is hard for
some people to reconcile with their gut feelings about
relativistic causality.
As far as I can tell, the MWI is not physics at all, but
rather metaphysics. It is a long-winded shaggy-dog story
that doesn't tell us anything that the equations of QM
didn't already tell us. It is a crutch that may help
some people let go of their inexact gut feelings about
relativistic causality.
Isaac Newton achieved the same goal in far fewer words when
he said "Hypotheses non fingo." That is, if you try to
imagine the rules of QM as being implemented in terms of
gears and machinery, you will never get it right ... just
as you will never be able to properly describe the operation
of the Maxwell equations in terms of "lines of force".
The MWI offers to replace overly-simple notions of the
"machinery" that enforces the laws of physics with a new
type of "machinery" that is capable of explaining _anything_.
It is therefore not a scientific theory at all. As Popper
would say, it is unfalsifiable ... it can "explain" magic
and miracles just as easily as it "explains" QM.
Fran Poodry wrote:
(only 2 more weeks of class for them).
Spending the last two weeks of HS studying waves seems
like a very reasonable thing to do. You can tell 'em
the wave equation is useful for understanding water-waves,
sound, light, and everything else ... and I really mean
everything, since QM tells us that everything obeys a
wave equation.
(Waves are necessary for understanding QM, but not by
themselves sufficient.)