If correct, Bell's Theorem rules out local variables and suggests a superdeterministic for to the Universe?

Question

If Bell's Theorem is correct and Quantum Mechanics cannot rely upon 'local variables'. Bell suggests that a probable solution is the existence of a Super-determined order upon the construct of our Universe. Bell stated the following during a radio interview in the 1980s:

There is a way to escape the inference of superluminal speeds and spooky action at a distance. But it involves absolute determinism in the universe, the complete absence of free will. Suppose the world is super-deterministic, with not just inanimate nature running on behind-the-scenes clockwork, but with our behavior, including our belief that we are free to choose to do one experiment rather than another, absolutely predetermined, including the "decision" by the experimenter to carry out one set of measurements rather than another, the difficulty disappears. There is no need for a faster than light signal to tell particle A what measurement has been carried out on particle B, because the universe, including particle A, already "knows" what that measurement, and its outcome, will be." (BBC Interview with Bell 1985)

Is there further evidence to confirm or reject a Super-determined Universal Construct, outside of John Bell's Theorem?

Answer 1

You're somewhat misreading his words there. rules out local variables and suggests superdeterminism -- instead, what he's saying is it rules out local variables UNLESS there's superdeterminism.

Superdeterminism is a potential way to keep local realism in tact, is what Bell is saying.

BUT it is in my opinion a completely untenable approach. The superdeterminism answer to the violation of Bell's Inequalities basically amounts to, "The entire universe works according to local realism, BUT the entire universe has conspired to make itself look like local realism is not the case". Though my opinion is probably not worth much.

Answer 2

First of all, we do not need superdeterminism: QM is OK as it stands without it. Superdeterminism seems to be necessary if we do not believe in the standard formulation of QM and we want a hidden variable theory which is local and realistic and can explain the phenomenology of QM.

Actually the Bell theorem, together with the results of experiments accumulated along the years, imply that there is no local realistic hidden-variable theory capable to explain the phenomenology of Quantum Mechanics. All that is true provided all loopholes in interpreting the above experimental data which should confirm the violation of the CHSH inequality are fixed. One of these loopholes (I think the only one remaining) regards superdeterminism, the last apparent (much more philosophical than physical) chance to keep both locality and realism in a hidden variable theory.

What is nowadays named "Bell theorem" is actually a statement of this type: "every local realistic hidden-variable theory capable to explain the phenomenology of QM must satisfy the CHSH inequality".

Realistic means that all observables are always defined (this is not the case for QM, as there exist incompatible observables). Local means that no superluminal transmission of physical information is permitted.

This reformulation of Bell's results is recent (this century) and I think it is due to Legget.

You cannot find that type of statement in the famous 1964 paper by Bell. There, a more elaborated philosopical position was proposed, relying on the original EPR analysis.

Furthermore the used inequality in that paper was not the CHSH one, but another version (the proper Bell inequality) much more difficult to experimentally test (however Clauser did it, I think in 1969).

I would like to finally stress that, actually, there is a realistic non-local hidden variable theory observationally equivalent to the standard non-relativistic QM. That is the deBroglie-Bohm theory.

Answer 3

Bell's theorem is the statement of an inequality derived from a pair of simple assumptions. So, any statement that implies that the theorem is wrong, would imply that he (and everybody else who checked it) made a mistake in the derivation. So, I'd say it is reasonable to accept that the theorem is correct.

The irony is that Bell's theorem is violated by nature, as demonstrated by experiments that have recently been awarded the Nobel prize. What this mean is not that Bell's theorem is not correct, but that one or both of the assumptions must be wrong. This is where we are with our scientific understanding of quantum mechanics.

Many people are not happy with that, so they try to come up with ways to "interpret" it. But those interpretations are in general non-scientific because there are no ways to determine whether they are correct through experimental observations. I suspect (correct me if I'm wrong) that super-determinism is one of those non-scientific interpretations.