Home › Forums › 2015 International Workshop on Quantum Foundations › Bohm’s theory › God knows where all the particles are! › Reply To: God knows where all the particles are!
Ok Travis, maybe we are getting somewhere.
For (1) I would just ask you to avoid terms like “directly observable”. Not even position is in BM, as you well know.
Does BM ever make “exactly” the right predictions? Surely not, because this depends on the additional assumptions. Actually, no theory ever makes “exact” predictions. You will realize this when you actually, finally, maybe, do analyze concrete situations. What you will need is the combination of whatever “exact” mathematical framework with a lot of dirty stuff, rough estimates, approximate models and all that. I will be the last person to hold that against BM. What I do object to is your pretending that you don’t need that.
Of course, I am aware that none of you guys is actually interested in concrete physics, and that that is not the aim of BM anyway. But even when you want to just do in-principle physics, you should be more explicit about what kinds of assumptions will be needed. That is part of the theory. The simplicity of “just two equations” simply is a lie.
What I expect will turn out is this: You will need the same kind of assumptions that QM needs (maybe suitably translated to BM language) PLUS some additional ones about orthogonality of macroscopic wave functions if you actually try to bring in effective wave functions and want them to satisfy Schrödinger’s eq. (See Rainer Plaga’s thread). The plausibility of these will need to be analyzed. Maybe someone even comes up with some theoretical arguments.
It may be that BM “provides a theory in which it seems possible in principle” to analyze a measurement. It just hasn’t been done except by blanket nostrification of QM. So before you call anyone a hypocrite, clean up your own act. And please, please, drop those silly claims of “exactness”, which only show that you have no idea of how physics works.
On that note, your desciption of operational QM as a theory “in which literally new ad hoc rules are just made up out of whole cloth and postulated on no grounds whatever except that they seem to be needed because the basic micro-dynamical axioms started to output nonsense” is very interesting. Where did you get that? Do you have a random generastor in the basement? It certainly does not relate to anything I ever did in the field or have seen done.