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> The best models Yes, models. But a model doesn't need to be "real", it just models something real to a certain extent. But models tend to break down if you l

by kawa 2y ago

> The best models Yes, models. But a model doesn't need to be "real", it just models something real to a certain extent. But models tend to break down if you look close enough, and I think this may also happen to QM at some point. Bell's Theorem doesn't rule out determinism, it only rules out hidden variables. If the universe is non-local, Bell's theorem fits well with determinism. > We don't live in a billiard ball universe We do - at least as long we look at clumps of matter. The billiard ball universe breaks down if we look at the constituents of matter but somehow it re-remerges if we put enough of those constituents together. It's probably the biggest riddle in Physics why this happens. But it does.

titzer 2y ago
> But models tend to break down if you look close enough, and I think this may also happen to QM at some point. Sure, but there's absolutely nothing to suggest that it will be some kind of deterministic computation underneath. > We do - at least as long we look at clumps of matter. Not even. Even non-quantum clumps of matter are influenced by continuous fields and dilation effects from both special and relativity. Even without QM, our universe is not efficiently simulatable on our computational models because of general relativity.
- kawa 2y ago
  > Sure, but there's absolutely nothing to suggest that it will be some kind of deterministic computation underneath The universe behaves very deterministically if we look at "clumps of matter". Why is it this way when this determinism isn't already part of the "base"? For me that's at least a "suggestion". Not a proof of course, but still a hint. > ... because of general relativity. General relativity doesn't fits together with QM, so either one is (or both are) "wrong" (in the sense that they only approximate reality to a certain degree). I'm even sceptical about special relativity: It's a good model and works well in most occasions, but it may still be wrong on a fundamental level. Most of the assumptions under which Einstein proposed SR (no QM, static universe) don't hold anymore.
  - LegionMammal978 2y ago
    > The universe behaves very deterministically if we look at "clumps of matter". Why is it this way when this determinism isn't already part of the "base"? For me that's at least a "suggestion". Not a proof of course, but still a hint. Just because a system is randomized doesn't mean it's not predictable: when measured in certain ways, it will statistically tend to clump around certain states. Suppose that every second, I flip a magic random coin and walk either 2 feet forward or 1 foot backward. Then after a million seconds, you'll quite probably find me about half a million feet from where I started. Small-scale random processes can easily create something predictable on the large scale. Still, I wouldn't characterize "clumps of matter" as being deterministic even in our everyday lives. There are many chaotic systems in this world, e.g., the weather, which can amplify randomness on the molecular level into a completely different state. Even the orbit of the Earth becomes unpredictable after several million years. > I'm even sceptical about special relativity: It's a good model and works well in most occasions, but it may still be wrong on a fundamental level. Most of the assumptions under which Einstein proposed SR (no QM, static universe) don't hold anymore. Special relativity is already 'wrong' in that it doesn't predict any of our observations of general relativity. But it unavoidably has plenty of truth in it, in that it is very succesful at predicting an identical speed of light for all observers, and the effects (e.g., time dilation) that that implies. Any superseding theory has to explain the same observations, at which point special relativity will continue to act as a useful model for the large-scale effects.
    - kawa 2y ago
      > Just because a system is randomized doesn't mean it's not predictable That's of course true (In fact I tend to also believe in a non-deterministic universe "at the core"). But if determinism falls out in the end, it's still a hint that there may also be deterministic effects at the root. Current observation can't rule that out, it's just our model which assumes pure randomness. But there are lot's of possibilities how randomness can sneak in into QM which doesn't contradict obserservation. And unless we solve the measurement problem in QM (by finding a unified theory from which both Schoedingers equations and Borns rule can be derived), it's still an open question. So considering it solved today is quite premature. > ... chaotic systems ... That's still deterministic. Sure, there may be some influence from quantum effects which then are amplified, but the dynamic of the chaotic system itself is still deterministic. > (SR) ... predicting an identical speed of light for all observers That's not really true. "identical speed of light for all observers" is an observation which was replicated quite often. SR is a way to explain this observation, but there before SR Lorenz already had a different model explaining it too. SR won, because Lorenz used an (at the time) unobservable "ether" and Einstein argued that its better to use Occams Razor and throw this "ether" away. But Einstein didn't now about QFT, the Big-Bang and the microwave-background - which all contradict Einsteins assumptions: QFT uses an "ether-like" vacuum, the Big-Bang created a "T=0" for the universe and with the microwave-background also an absolute reference frame for an absolute time. This in all contradicts SR, so maybe SR is really wrong on a global level. Which in turn would allow a non-local, realistic interpretation of quantum measurements because without SR simultaneity could be back on the table.

by kawa 2y ago

titzer 2y ago

> But models tend to break down if you look close enough, and I think this may also happen to QM at some point. Sure, but there's absolutely nothing to suggest that it will be some kind of deterministic computation underneath. > We do - at least as long we look at clumps of matter. Not even. Even non-quantum clumps of matter are influenced by continuous fields and dilation effects from both special and relativity. Even without QM, our universe is not efficiently simulatable on our computational models because of general relativity.

kawa 2y ago
> Sure, but there's absolutely nothing to suggest that it will be some kind of deterministic computation underneath The universe behaves very deterministically if we look at "clumps of matter". Why is it this way when this determinism isn't already part of the "base"? For me that's at least a "suggestion". Not a proof of course, but still a hint. > ... because of general relativity. General relativity doesn't fits together with QM, so either one is (or both are) "wrong" (in the sense that they only approximate reality to a certain degree). I'm even sceptical about special relativity: It's a good model and works well in most occasions, but it may still be wrong on a fundamental level. Most of the assumptions under which Einstein proposed SR (no QM, static universe) don't hold anymore.
- LegionMammal978 2y ago
  > The universe behaves very deterministically if we look at "clumps of matter". Why is it this way when this determinism isn't already part of the "base"? For me that's at least a "suggestion". Not a proof of course, but still a hint. Just because a system is randomized doesn't mean it's not predictable: when measured in certain ways, it will statistically tend to clump around certain states. Suppose that every second, I flip a magic random coin and walk either 2 feet forward or 1 foot backward. Then after a million seconds, you'll quite probably find me about half a million feet from where I started. Small-scale random processes can easily create something predictable on the large scale. Still, I wouldn't characterize "clumps of matter" as being deterministic even in our everyday lives. There are many chaotic systems in this world, e.g., the weather, which can amplify randomness on the molecular level into a completely different state. Even the orbit of the Earth becomes unpredictable after several million years. > I'm even sceptical about special relativity: It's a good model and works well in most occasions, but it may still be wrong on a fundamental level. Most of the assumptions under which Einstein proposed SR (no QM, static universe) don't hold anymore. Special relativity is already 'wrong' in that it doesn't predict any of our observations of general relativity. But it unavoidably has plenty of truth in it, in that it is very succesful at predicting an identical speed of light for all observers, and the effects (e.g., time dilation) that that implies. Any superseding theory has to explain the same observations, at which point special relativity will continue to act as a useful model for the large-scale effects.
  - kawa 2y ago
    > Just because a system is randomized doesn't mean it's not predictable That's of course true (In fact I tend to also believe in a non-deterministic universe "at the core"). But if determinism falls out in the end, it's still a hint that there may also be deterministic effects at the root. Current observation can't rule that out, it's just our model which assumes pure randomness. But there are lot's of possibilities how randomness can sneak in into QM which doesn't contradict obserservation. And unless we solve the measurement problem in QM (by finding a unified theory from which both Schoedingers equations and Borns rule can be derived), it's still an open question. So considering it solved today is quite premature. > ... chaotic systems ... That's still deterministic. Sure, there may be some influence from quantum effects which then are amplified, but the dynamic of the chaotic system itself is still deterministic. > (SR) ... predicting an identical speed of light for all observers That's not really true. "identical speed of light for all observers" is an observation which was replicated quite often. SR is a way to explain this observation, but there before SR Lorenz already had a different model explaining it too. SR won, because Lorenz used an (at the time) unobservable "ether" and Einstein argued that its better to use Occams Razor and throw this "ether" away. But Einstein didn't now about QFT, the Big-Bang and the microwave-background - which all contradict Einsteins assumptions: QFT uses an "ether-like" vacuum, the Big-Bang created a "T=0" for the universe and with the microwave-background also an absolute reference frame for an absolute time. This in all contradicts SR, so maybe SR is really wrong on a global level. Which in turn would allow a non-local, realistic interpretation of quantum measurements because without SR simultaneity could be back on the table.