The 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

particle/detector.

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.