I am not a boy because my parents observed my penis at the 12 week echo. I am a boy because the sperm cell that made me, carried the right chromosome. It was decided at fertilization. Even if my parents never observed me, I would still be a boy.
The experiment described in the Veritasium video splits a particle in an electron and a proton. They must have opposite spin and that is measured at the time of observation. Than there’s a whole discussion about faster than light communication, but if the spin is given at the moment of creation, both will have the opposite spin from the start. It can still be random and measurements will still have a 25% failure rate.
What am I missing? Can the spin change between creation and measurement?
What happens if a particle doesn’t get observed, does it not have spin?
Bell’s theorem does not disprove hidden variables as it relies on various assumptions.
(1) Locality. The EPR paper already proves a non-hidden variable model of locality is mathematically impossible, so if you are rejecting hidden variables, you’re already rejecting locality, so Bell’s theorem no longer applies.
(2) Fundamental arrow of time, more specifically that systems can only be affected by events in a local causal chain down its backwards light cone but not its forward light cone. This requires a rigorous definition of which temporaral direction is “forwards” vs “backwards,” something Bell never provides. Without it, there is no obvious reason that causality should flow in one direction and not the other. A model where causality is indifferent to the arrow of time is called time-symmetric.
(3) Free will, the assumption that humans have the ability to make decisions that are statistically independent of all physical phenomena (note that the assumption is that they “have the ability to” not all decisions are statistically independent of all physical phenomena). If there is a law of physics that enforces certain correlations such that a system cannot evolve in a way to break those correlations, given that humans are also made of particles that obey the laws of physics, humans would also be unable to make the conscious decision to break those correlations, leading to an unintentional bias in each experiment. Dropping the free will assumption gives you what is called superdeterminism.
Bell himself did not believe he ruled out hidden variables but was the biggest advocate of them. Bell thought the free will assumption was necessary for the scientific method and that time-symmetry was not even worth considering. He also understood that the EPR paper succeeding in completely ruling out local non-hidden variable models. Hence, he concluded that his theorem just rules out local hidden variable models, not hidden variable models in general, and if you combine that with the results of the EPR paper that rule out local non-hidden variable models, then the natural conclusion is that Bell ruled out locality as a whole.
Indeed, that was Bell’s actual conclusion and belief regarding his theorem. Bell regarded his finding as having ruled out locality, not hidden variables. Bell was a major proponent of nonlocal hidden variable models, he even wrote a paper trying to develop Bohm’s pilot wave theory and accused other physicists of intentionally trying to keep quantum mechanics seemingly more mysterious by sweeping it under the rug.