• i_love_FFT@jlai.lu
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    5 days ago

    What if some parts of the universe are deterministic, and some others aren’t? Or that is is deterministic sometimes, but sometimes it is not?

    Then, would it mean that initiating a chain of deterministic events that eventually causes suffering makes me responsible for this suffering?

    What if i choose to cut taxes because i think I’ll have more money, but it causes a series of events that end up increasing organised crimes? What if it was always the deterministic result of that choice, but the choice itself was not deterministic and I could have chosen not to do it?

    • queermunist she/her@lemmy.ml
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      4 days ago

      Oh it’s even worse.

      The universe is indeterministic. It’s probabilistic and uncertain, but that doesn’t mean you actually have a choice. Your “choices” are just determined by quantum dice rolls.

      Anything can happen, nothing is certain, but you still don’t actually exercise will over reality.

      • CarbonIceDragon@pawb.social
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        4 days ago

        Tbh I dont think that this is actually incompatible with determinism, since the mechanism by which the future is predetermined doesnt necessarily have to be that all causes only have one possible effect associated with them. I mostly suspect the universe is deterministic because I suspect (though this is only a suspicion that I cannot prove) that the universe has block time and therefore that, even if random events with no clear “this must lead to that” chain exist, the future is predetermined merely by “already” existing along some time axis. Sort of like how if you had a character in a flipbook roll a die, and nothing earlier in the flipbook forces the die to have to land on one particular number to keep the plot self-consistent, the outcome of the die will still always be the same, because the pages where its result is shown already have been drawn.

        • queermunist she/her@lemmy.ml
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          4 days ago

          Sure, but now you have to make a bunch of assumptions about things we can’t test or observe to keep the universe consistent with determinism. It’s not impossible that the universe is predetermined, but there’s just no reason to believe it is. You’re making more of an aesthetic argument than a scientific one.

          • CarbonIceDragon@pawb.social
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            4 days ago

            It wasnt really an argument at all, except for the part that randomness isnt incompatible with determinism. I dont have a proper scientific reason for suspecting the future already exists, it just feels somehow “simpler” since it doesnt require assuming that the time dimension is somehow particularly different from space dimensions.

      • Amnesigenic@lemmy.ml
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        4 days ago

        That’s assuming that our current understanding of quantum mechanics is even close to accurate, just because we haven’t figured out how to predict the outcomes yet doesn’t mean it can’t be done

        • queermunist she/her@lemmy.ml
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          4 days ago

          That’s called Hidden Variable Theory, but there’s also no indication that this is how the universe works and everything we find just reinforces indeterminism and uncertainty.

          The most notable development is the math working out to make hidden variables irrelevant i.e. they do not actually help us better describe reality or predict outcomes of measurement.

          The math doesn’t seem to care whether God is rolling dice or not.

          • pcalau12i@lemmy.world
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            4 days ago

            Speaking of predicting outcomes implies a forwards arrow of time. As far as we know, the arrow of time is a macroscopic feature of the universe and just doesn’t exist at a fundamental level. You cannot explain it with entropy without appealing to the past hypothesis, which then requires appealing to the Big Bang, which is in and of itself an appeal to general relativity, something which is not part of quantum mechanics.

            Let’s say we happen to live in a universe where causality is genuinely indifferent to the arrow of time. This doesn’t mean such a universe would have retrocausality, because retrocausality is just causality with an arrow facing backwards. If its causal structure was genuinely independent of the arrow of time, then its causal structure would follow what the physicist Emily Adlam refers to as global determinism and an "all-at-once* structure of causality.

            Such a causal model would require the universe’s future and past to follow certain global consistency rules, but each taken separately would not allow you to derive the outcomes of systems deterministically. You would only ever be able to describe the deterministic evolution of a system retrospecitvely, when you know its initial and final state, and then subject it to those consistency rules. Given science is usually driven by predictive theories, it would thus be useless in terms of making predictions, as in practice we’re usually only interested in making future predictions and not giving retrospective explanations.

            If the initial conditions aren’t sufficient to predict the future, then any future prediction based on an initial state, not being sufficient to constrain the future state to a specific value, would lead to ambiguities, causing us to have to predict it probabilistically. And since physicists are very practically-minded, everyone would focus on the probabilistic forwards-evolution in time, and very few people would be that interested in reconstructing the state of the system retrospectively as it would have no practical predictive benefit.

            I bring this all up because, as the physicists Ken Wharton, Roderick Sutherland, Titus Amza, Raylor Liu, and James Saslow have pointed out, you can quite easily reconstruct values for all the observables in the evolution of system retrospectively by analyzing its weak values, and those values appear to evolve entirely locally, deterministically, and continuously, but doing so requires conditioning on both the initial and final state of the system simultaneously and evolving both ends towards that intermediate point to arrive at the value of the observable at that intermediate point in time. You can therefore only do this retrospectively.

            This is already built into the mathematics. You don’t have to add any additional assumptions. It is basically already a feature of quantum mechanics that if you evolve a known eigenstate at t=-1 and a known eigenstate at t=1 and evolve them towards each other simultaneously until they intersect at t=0, at the interaction you can seemingly compute the values of the observables at t=0. Even though the laws of quantum mechanics do not apply sufficient constraints to recover the observables when evolving them in a single direction in time, either forwards or backwards, if you do both simultaneously it gives you those sufficient constraints to determine a concrete value.

            Of course, there is no practical utility to this, but we should not necessarily confuse practicality with reality. Yes, being able to retrospectively reconstruct the system’s local and deterministic evolution is not practically useful as science is more about future prediction, but we shouldn’t declare from this practical choice that therefore the system has no deterministic dynamics, that it has no intermediate values and when it’s in a superposition of states it has no physical state at all or is literally equivalent to its probability distribution (a spread out wave in phase space). You are right that reconstructing the history of the system doesn’t help us predict outcomes better, but I don’t agree it doesn’t help us understand reality better.

            Take all the “paradoxes” for example, like the Einstein-Podolsky-Rosen paradox or, my favorite, the Frauchiger–Renner paradox. These are more conceptual problems dealing with an understanding of reality and ultimately your answer to them doesn’t change what predictions you make with quantum mechanics in any way. Yet, I still think there is some benefit, maybe on a more philosophical level, of giving an answer to those paradoxes. If you reconstruct the history of the systems with weak values for example, then out falls very simple solutions to these conceptual problems because you can actually just look directly at how the observables change throughout the system as it evolves.

            Not taking retrospection seriously as a tool of analysis leads to people believing in all sort of bizarre things like multiverses or physically collapsing wave functions, that all disappear if you just allow for retrospection to be a legitimate tool of analysis. It might not be as important as understanding the probabilistic structure of the theory that is needed for predictions, but it can still resolve confusions around the theory and what it implies about physical reality.

          • Amnesigenic@lemmy.ml
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            4 days ago

            That’s one theory about how it might work, our inability to come up with another way to explain the possibility of quantum determinism is not evidence against it

            • queermunist she/her@lemmy.ml
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              4 days ago

              It’s not that there aren’t other ways to explain the universe, but rather, none of those alternatives are more predictive or descriptive. Not only can’t we find hidden variables, we don’t need them.

              You can believe there are angels dancing on the heads of pins (or whatever) and that’s the hidden variable causing uncertainty, but there’s literally no reason to. You’re introducing addition unnecessary complexity when we can explain everything without it.

              • Amnesigenic@lemmy.ml
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                4 days ago

                Our inability to predict an outcome does not prove anything about the certainty of the outcome, our understanding of physics is incomplete and any conclusions you draw from incomplete information are necessarily assumptions, you felt compelled to describe that with reference to angels as a means of delegitimizing this fact because you’re emotionally invested in your preferred theory