1Bohm vs. Bohm's pilot wave
- Sep 21, 2000The motivation for this egroup was to answer certain mistaken ideas about
the de Broglie-Bohm theory (let's call it dBB).
One is that because Bohm went wacko in his old age, likening certain
aspects of dBB to mystical concepts, these aspects really do have
something to do with dBB.
It's true, dBB does invoke instantaneous influences between far separated
places--and just as Bohm himself pointed out--there's no reason to take
this as literally the case. As in many other physical theories, the idea
is that it doesn't happen instantaneously, just really fast. Fast enough
to be approximated as instantaneous in the context of current experiments.
Presumably at some point this breaks down, and experiments would stop
showing Bell inequality violations if the polarizers could be switched
fast enough. This means there's new physics there, which would require a
fuller theory, but we don't have it (or any experimental indications of
what it may be) at this point.
Some people like to say things like "There's a contradiction in Bohm's
theory because of the instantaneous influences." Or: "There's a
contradiction in general relativity because of the prediction of
singularities." These people do not understand that a physical theory does
not have to declare itself the absolute, metaphysical last word on a
certain arena of physics. It can be a brilliant, beautiful, precise
mathematical theory--and still acknowledge that it's not complete. That
certain approximations are made to brush over areas where the physics is
not understood yet, like what does a "singularity" look like in detail,
what is it's actual (finite) mass density--or: exactly how does a
polarizer setting super-luminally affect a far-separated
In this regard Bohm's theory has two merits:
1. unlike standard QM it explicitly faces up to the non-localities
(faster-than-light effects) which we know are simply a fact, whatever
interp of QM you support so long as it gives the correct QM predictions.
(This fact is a seldom grasped, or at least discussed, implication of
Bell's theorem + expts.)
2. unlike certain supposed relativistically local theories (like Little's
TEW), it does not pretend to be what it simply cannot be.
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