RandallB said:
As Vanesch pointed out early on the key difference between QM & CM is superposition. If CM can show that that is wrong, then QM is done for.
So if CM is to assume superposition is invalid, that leaves several paradoxes unresolved. CM must prove it has not just a “better” solution, but a complete and real solution to at least one of the basics (entanglement, double slit, electron not crashing into protons, etc.)
The point of this thread as Vanesch kicked it off is where CM is now and what it needs to do. (Not who as an idea that should crush any CMer from even trying) Other than producing a solution a start could also be made on refuting the negative prove against CM where Bell says CM cannot work. I really don’t see how any “complete proof” can be considered complete if it doesn’t lead to that any way. Certainly for CM that should be more important than superconductivity, even if it can be developed into another form of a negative proof against CM.
As to who will win this “race” how can we tell till we know, till then I’ve never been much for giving odds, so I’ll take the odds and bet on CM.
RB
I don't think theory A can prove theory B wrong or vice versa. You can only find out 2 possibilities:
- it can be shown that theory A and theory B will make the same predictions for experiment
- theory A and theory B make, in some cases, different predictions for experiment.
If you are in the first case, it is a matter of taste and you can argue until you grow a long beard over it. The interesting case is when you're in the second case. It is then sufficient to do one of those experiments where the predictions are different and you know that at least ONE theory will be falsified.
Ok, that sounded simple. But the situation QM - CM is not that easy.
Here we have: theory A versus an entire set of not yet clearly defined theories B, call it Bag C. Clearly, Bag C does not have many predictions for many things, because they are many of them and not even written down.
What Bell did, was: well, if I can make these basic assumptions about ALL theories of Bag C, then I can show that theory A will make, in certain cases, different predictions than all the theories of Bag C.
So we know that no theory of Bag C will ever be a theory that will bring us in the first case.
The problem is that the experiments suggested are difficult to put in place, and we can not do them, exactly in that way. We can do experiments that come close and use the elements of theory A exactly where they would make different predictions, but we need experimental corrections, also suggested by theory A, which make that some theories in Bag C can do the same. This is strongly suggestive that theory A is not wrong, but it is not excluded.
And of course the main problem is that we still have a whole bag of undefined theories Bag C, so for MOST phenomena which are handled well by theory A, nothing is said by the theories of Bag C. This was ZapperZ point: telling about how it is not impossible that some theory in Bag C can do all the same is nothing else but day dreaming.
It is correct that the scientific method only discriminates between two existing theories, not between an existing theory and a set of as yet undefined theories which could potentially maybe make the same predictions.
Now, imagine that CM proponents do a lot of work and finally come up with a classical theory that matches all of QM's predictions in those areas where it has been tested. Did CM now prove QM wrong ? No, of course not: QM ALSO made all these predictions. You can now maybe have an interpretational preference for CM, but if I wanted to, I could stick to QM, and CM DID NOT PROVE QM WRONG. Are we now in case 1, where it is simply a matter of taste to prefer one theory over another ? No, because of Bell's theorem: it means that SOME predictions of the CM theory to be develloped ALWAYS will be different from the QM predictions. So we only have to do those experiments, right ? Only this time it will be clear: there will not be loopholes because the CM theory will ALSO make precise numerical predictions of the outcomes (and not just an inequality).
One of both will win (or both will loose).
Imagine that the experiment proves QM wrong: it wasn't CM who falsified QM in that case: it was experiment. So we didn't really need the CM theory to falsify QM.
Imagine that the experiment proves QM right: all the work in CM for nothing.
So the situation is this:
- for the moment we have no CM theory that makes identical predictions as QM in ALL the areas where QM was successfully tested. It is only some HOPE by some that such a theory exists and can be worked out.
- If ever their hope is satisfied and they finally DO find such a theory that can make same predictions as QM in areas such as superconductivity, atomic and molecular spectra etc... then QM and CM are at that moment on an equal footing.
- finally experiment alone will decide between them, and QM will only be proved wrong when experiment falsifies it. Also, CM could be proven wrong.
That's why I honestly don't see the point in working on a CM until QM is falsified experimentally. The reason is that you have to work a lot and hope 2 times: first to FIND the CM theory that fits current QM (I'm far from convinced that that is a reasonable thing to look for), and second that the EXPERIMENT will falsify QM, something it hasn't done since about a century. That's taking a big bet.
I think it is much more "bet efficient" to just do experiments to test QM in all possible ways. As long as QM is not falsified, I don't see the point in looking for something else. And IF QM is falsified, we'll have a clear indication into what direction to look for. The thing that CAN be interesting in looking for CM's are suggestions for experiments.
