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Any evidence of any physical phenomena is probabilistic. And with Bell's inequalities, we know that for a fact.

eigenket 3y ago
This doesn't follow from Bell's inequalities. There are deterministic models of quantum mechanics which are compatible with Bell's theorem.
- golergka 3y ago
  That's why I argue with people on the internet — to be corrected and learn new things in the process! Please tell more.
  - eigenket 3y ago
    Bells theorem says that he predictions of quantum mechanics are incompatible with any "local hidden variable model". Experiments show that the real world appears to follow the predictions of quantum mechanics, so no local hidden variable model can explain what we see in these experiments. Therefore all you need to understand is what a "local hidden variable model" is, and what the lack of one would mean. You should think of doing measurements in quantum mechanics as something like flipping a biased coin, or rolling a biased dice. Every time you do a measurement you get some outcome (maybe heads or tails or a number from 1 to 6) but the probabilities aren't generally the same, they're biased in a way which tells you something about the system. They can even be biased so much that the outcomes are deterministic (0 and 1 are still probabilities). When you flip a coin or roll a dice, the outcomes are random from your point of view, but there isn't really any fundamental randomness going on. There's a bunch of data about how your hand moves, and the local wind speed and pressure and the physical characteristics of the coin which if you knew them then you'd be able to predict the outcome with certainty. People have even been able to build robots which can reliably flip coins to always get a desired outcome. This "extra information" that makes the outcome deterministic if you know it we could call hidden variables. Its "hidden" because you don't generally know it. If Bell's theorem said that there was no hidden variables model consistent with the predictions of quantum mechanics we'd be done now. We would have decided that quantum mechanics is fundamentally probabilistic and no extra hidden information could exist to make it deterministic. But Bell emphatically doesn't do that. The theorem says there is no local hidden variable model consistent with quantum mechanics. So what does "local" mean here? For that you can imagine that instead of rolling one dice I'm rolling one here, you're rolling a second one wherever you live, our friend on Mars is rolling a third one, etc. A hidden variable is "local" if it only affects the dice in once location. Bell's theorem says that if you want to have a hidden variable model that reproduces quantum mechanical predictions then it needs to be nom-local. That is the hidden variable has to affect the experiment here, and the one with you, and the one on Mars all at the same time. We consider that non-local hidden variables are unlikely because they're essentially magic, they need to affect things arbitrarily far away from each other all at the same time. Amongst other things this is wildly on conflict with special relativity.
    - golergka 3y ago
      > We consider that non-local hidden variables are unlikely Doesn't that essentially mean the same as > If Bell's theorem said that there was no hidden variables model consistent with the predictions of quantum mechanics we'd be done now. ?
      - eigenket 3y ago
        Unlikely does not mean the same as impossible, so no. There are also some "loopholes" in the story I told above. For example the many worlds interpretation of quantum mechanics is completely local and deterministic, but weird enough that the standard formulation of hidden variables models doesn't apply to it.
marblar 3y ago
> We know that for a fact Probably.
- ducttapecrown 3y ago
  The only true facts are the useless tautologies... Sad for the theory of knowledge, truly...
BobaFloutist 3y ago
Any evidence of any physical phenomena is probablystic? Maybe this is true of you go deep enough into mathematical/philosophical/quantum rabbit holes, but it doesn't pass the intuitive smell test - I could off-hand name tens of physical phenomena that will perform as expected 100% of the time, deterministic physics (on the macro scale, at least) are like the entire basis for the scientific method.
- para_parolu 3y ago
  You may think you have 100% probability of event but then simulation glitches and outcome is different.
  - BobaFloutist 3y ago
    Ok but that hasn't been scientifically observed, so it's more of a religion than a theory.

This doesn't follow from Bell's inequalities. There are deterministic models of quantum mechanics which are compatible with Bell's theorem.

golergka 3y ago
That's why I argue with people on the internet — to be corrected and learn new things in the process! Please tell more.
- eigenket 3y ago
  Bells theorem says that he predictions of quantum mechanics are incompatible with any "local hidden variable model". Experiments show that the real world appears to follow the predictions of quantum mechanics, so no local hidden variable model can explain what we see in these experiments. Therefore all you need to understand is what a "local hidden variable model" is, and what the lack of one would mean. You should think of doing measurements in quantum mechanics as something like flipping a biased coin, or rolling a biased dice. Every time you do a measurement you get some outcome (maybe heads or tails or a number from 1 to 6) but the probabilities aren't generally the same, they're biased in a way which tells you something about the system. They can even be biased so much that the outcomes are deterministic (0 and 1 are still probabilities). When you flip a coin or roll a dice, the outcomes are random from your point of view, but there isn't really any fundamental randomness going on. There's a bunch of data about how your hand moves, and the local wind speed and pressure and the physical characteristics of the coin which if you knew them then you'd be able to predict the outcome with certainty. People have even been able to build robots which can reliably flip coins to always get a desired outcome. This "extra information" that makes the outcome deterministic if you know it we could call hidden variables. Its "hidden" because you don't generally know it. If Bell's theorem said that there was no hidden variables model consistent with the predictions of quantum mechanics we'd be done now. We would have decided that quantum mechanics is fundamentally probabilistic and no extra hidden information could exist to make it deterministic. But Bell emphatically doesn't do that. The theorem says there is no local hidden variable model consistent with quantum mechanics. So what does "local" mean here? For that you can imagine that instead of rolling one dice I'm rolling one here, you're rolling a second one wherever you live, our friend on Mars is rolling a third one, etc. A hidden variable is "local" if it only affects the dice in once location. Bell's theorem says that if you want to have a hidden variable model that reproduces quantum mechanical predictions then it needs to be nom-local. That is the hidden variable has to affect the experiment here, and the one with you, and the one on Mars all at the same time. We consider that non-local hidden variables are unlikely because they're essentially magic, they need to affect things arbitrarily far away from each other all at the same time. Amongst other things this is wildly on conflict with special relativity.
  - golergka 3y ago
    > We consider that non-local hidden variables are unlikely Doesn't that essentially mean the same as > If Bell's theorem said that there was no hidden variables model consistent with the predictions of quantum mechanics we'd be done now. ?
    - eigenket 3y ago
      Unlikely does not mean the same as impossible, so no. There are also some "loopholes" in the story I told above. For example the many worlds interpretation of quantum mechanics is completely local and deterministic, but weird enough that the standard formulation of hidden variables models doesn't apply to it.

marblar 3y ago

> We know that for a fact Probably.

ducttapecrown 3y ago
The only true facts are the useless tautologies... Sad for the theory of knowledge, truly...

BobaFloutist 3y ago

Any evidence of any physical phenomena is probablystic? Maybe this is true of you go deep enough into mathematical/philosophical/quantum rabbit holes, but it doesn't pass the intuitive smell test - I could off-hand name tens of physical phenomena that will perform as expected 100% of the time, deterministic physics (on the macro scale, at least) are like the entire basis for the scientific method.

para_parolu 3y ago
You may think you have 100% probability of event but then simulation glitches and outcome is different.
- BobaFloutist 3y ago
  Ok but that hasn't been scientifically observed, so it's more of a religion than a theory.