One of my colleagues are a magician and I love talking with him about magic tricks and it is clear that we as humans are easily fooled by magic tricks and it is a delight to try bust the trick and figure out how it is done. My general rule of thumb are that if you have something that is weird or magical. There is a trick behind it.

Now over to a experiment related to the double slit experiment of quantum mechanics that in popular press is known as spooky action at distance. The basic principle comes from the fact that we know that some properties like angular momentum is preserved if there is no external force acting on the system. So if this system has zero angular momentum and spontaneously split in two parts and both parts are either +1 or -1 we know that this system must add up to 0. On this determinism we can deduce a condition called Bell's theoream, that essentially mean that if you violate it you sometimes measure two 1's or -1's in both part that split. Now QM magically violates Bell's inequality and the consequences of this i philosophically speaking weird strange and looks like true magic.

The first red flag when it comes to discussions about these experiments that enters are that people refer to way to general assumptions. You do not see a mathematical proof that this deterministic model can explain Quantum Mechanics but they say that every mathematical model that is deterministic can't reproduce quantum mechanics hence it's weird consequences are just what nature is. Now the problem with such a general statement are that we can make up deterministic models where we simply have no chance of knowing all parameters in it and this essentially means a practical non determinism (no it is not hidden variables, read on).

So if we agree about that the system we talked about preserves angular momentum and that our system is deterministic how can we violate Bells inequality? If you study the literature you will know that there are a bunch of loopholes and this is what we should aim for, find out which loophole exists or in other words that we do not measure what we think we are measuring. And I would claim "we excluded all possible deterministic models" also means that we avoided "all possible loopholes" Now here is one of the main weaknesses you find in discussions about this. "all possible loopholes" are totally shoveled under the rug and this also shows why you should take care to define the system you claim the result for more careful than just state "a deterministic system". This is important because QM could be a model that you can deduce from a deterministic system but with a loophole that we have no chance to resolved and we must punt on a perfect measurement.

A glaring problem in the formulations of the slit experiments are that everywhere they treat the object as a point. This is a hint. We should of cause prove our system for objects that are extended in space and where the forces in our measurements act in multiple places of the body. Also with a rigid body comes preccession which essentially means that the object wobble through space where angular momentum varies in time which means essentially can mean that you can get a chaotic selection of the measurement and as we can't control the exact motion we can get both a +1 or both a -1 in our measurement so this is most likely a process that one need to address in order to maintain that QM is weird and we must accept that. Now it is possible that scientists has covered this loophole but I'm sceptical and I would like to see a paper doing exactly that.