zenith8 said:
It's a postulate in orthodox QM. In deBB theory, the orthodox formalism (operators as observables, Born rule etc) emerges only as an equilibrium phenomenology and is not required at the fundamental level, where there is only a partial differential equation for a field in configuration space plus a guidance equation.
Sure, but deBB simply embeds a deeper postulate underneath the Born rule, and as far as I can see, it doesn't actually accomplish anything beyond giving us the Born rule and the Schroedinger equation in a way that is every bit as much ad hoc as those two are. They are already the postulates of QM, so deBB isn't really any different-- when any differences it predicts are unmeasurable anyway.
But everyone who's looked at it carefully sees that it does..
So your main argument is going to be that everyone who understands deBB becomes a convert, so any non-converts don't understand it? Here's the problem with that logic--
everyone thinks that way about their
own interpretation. Everyone.
By quasi-classical do you mean anything other than 'particles exist'?
Yes, I mean a lot more than "particles exist." In particular, I mean that particles behave deterministically, and that everything that happens is controlled by the initial state. That is the most classical possible concept one can have, and preserving that mentality is clearly the primary motivation for deBB. So here are the three interpretations in a nutshell:
CI: God might not play dice, but people do when they do physics.
MWI: God doesn't play dice, but it looks that way because we don't see the full unity of all the worlds, we only see our own corner.
deBB: God doesn't play dice, but it looks that way because we don't see the full information locked up in the initial conditions.
Indeed, my contention is not that the more you know about any of these, the more you think they are right, my contention is that the more you know about all of these, the more you see they aren't really saying anything scientifically different at all-- they merely express philosophical priorities. Occasionally you hear MWI and deBB proponents claiming their approaches do make different predictions that could be verified, but you never actually see anyone trying to verify those different predictions. Funny that.
If that's what you mean, well, so what? Surely it's an interesting point that, despite 80 years of argument, the only known and generally accepted (even by unusualname!) way to explain the Born rule is to imagine that particles don't wink out of existence as soon as you cease to look at them, in which case it follows immediately. That single definition in the meaning of a word ('probability' referring to 'being at x' rather than 'being measured at x') is ultimately the only difference between BM and OQM - everything else is a natural consequence.
To the empiricist, there is not the
slightest difference in those two concepts, scientifically speaking. The differences are pure 100% philosophical ontology, which has been my main point.
No, BM leads to suggestions for potential ways to decide experimentally the existence of non-Born-rule states (see my earlier post and the voluminous literature).. And BM is not an interpretation, it's a different theory (separate axioms/postulates plus different predictions - at least away from quantum equilibrium).
So it is often claimed. Still, nobody ever actually tests that, now do they? Where are all the tests of those different predictions? Lots of angels on pins is all I see, and the occasional ludicrous experiment doing some kind of average over "partial measurements" that we are somehow supposed to interpret as something different from the usual ensemble averages that just give classical wave mechanics. No, I haven't seen squat in the way of evidence that deBB is really a different theory, that emperor has no clothes. It's not surprising really-- deBB was not formulated as a new theory responding to any new data than what QM already explained, it was always just a way to reverse-engineer QM in such a way as to preserve initial-state-encoded determinism. Surely you can see that about it, it's no kind of secret.
No, you can make the the theory deterministic or non-deterministic as you wish, as I already explained.
And as I explained, that was never the point of it. Take the determinism away from deBB, and all you have is something a bit less neoclassical. It's fine if you like to have a way to think of QM such that particles have classical properties, but that is demonstrably all anyone has ever gotten from it. It's basically a proof that QM does not require the claims that people often make on it, which is of value to prove, but it is hardly some kind of better theory. That's just empty claims.
