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> Can you build non-determinism out of deterministic pieces? Yes. Pseudo-random generators are deterministic on lower level, yet they effectively non-determini

by js8 7y ago

> Can you build non-determinism out of deterministic pieces? Yes. Pseudo-random generators are deterministic on lower level, yet they effectively non-deterministic in the sense that you cannot easily predict next value. Or you can just take a system with large number of interacting particles - even if behavior of each of them is determined, the system as a whole is hard to predict. Converse is also possible, you can build effectively deterministic system on top of a non-deterministic one. We do that with computers, we have digital computers (deterministic) on top of solid-state physics, which is non-deterministic due to interactions of electrons and the material. This is not really a paradox, since at the higher level you only consider macrostates, so the fact that the microstates, which you consider at the lower level, are (non-)deterministic doesn't really matter.

trevyn 7y ago
Determinism and predictability are distinct concepts, it is epistemically dangerous to conflate them.
- js8 7y ago
  I agree that they are different because determinism is a (mathematical) property of the model, while the predictability (with respect to class of models) is observed.
- dlkf 7y ago
  Well put. Compatibilist arguments typically hinge on some bait and switch and this is a popular one. The author does this exact thing in his weather example: > At the level of individual air molecules, there is no such thing as weather. Perhaps the system at that very fine-grained level of description would indeed behave deterministically according to classical physical laws, but as you move to a more macroscopic description, you abstract away from this microphysical detail. That is not driven by ignorance on our part, but by the explanatory need to focus on the most salient regularities. > When you consider the macroscopic weather states, the system is not deterministic, but stochastic, or random. The high level weather pattern is just like the output of the pseudorandom number generator. It appears stochastic to someone who is only given the high level description, but it is still deterministic in the actual world. Given the Laplace's demon description of the system, there is no room for alternative possibilities. I think the author is only added the part I have bolded to try and deflect this. He is saying "we don't want the Laplace's demon description of the system, we just want the high level precis." Weirder still, he seems to suggest that getting the Laplace's demon is a realistic possibility, which obviously it's not. But the fact is it doesn't matter whether it's possible for a human to get the Laplace's demon description, or whether you actively pursue it or whatever - if your accept that it's there, as List seems to, then it fully determines the higher level phenomena and this idea about higher level indeterminacy is moot.
tpetrina 7y ago
> in the sense that you cannot easily predict next value Easily or _in principle_? Do not conflate our physical constraints with the actual mechanism behind the scene. Free will is not about our own ignorance or inability, it is the principal thing.
- js8 7y ago
  These are constraints from computational complexity. My point is the question "is it deterministic" is wrong without considering the level of detail you're looking at. Even in deterministic universe, a roll of dice is considered to be undeterministic, and this is good enough for casinos. If you're asking "in principle", then it might as well be unknowable because, as I pointed out, how we might observe the system to be (our model of it is deterministic or not) doesn't have to correspond at all whether it is actually deterministic or not at the lower level. So there always can be another level which can behave differently.

by js8 7y ago

trevyn 7y ago

Determinism and predictability are distinct concepts, it is epistemically dangerous to conflate them.

js8 7y ago
I agree that they are different because determinism is a (mathematical) property of the model, while the predictability (with respect to class of models) is observed.
dlkf 7y ago
Well put. Compatibilist arguments typically hinge on some bait and switch and this is a popular one. The author does this exact thing in his weather example: > At the level of individual air molecules, there is no such thing as weather. Perhaps the system at that very fine-grained level of description would indeed behave deterministically according to classical physical laws, but as you move to a more macroscopic description, you abstract away from this microphysical detail. That is not driven by ignorance on our part, but by the explanatory need to focus on the most salient regularities. > When you consider the macroscopic weather states, the system is not deterministic, but stochastic, or random. The high level weather pattern is just like the output of the pseudorandom number generator. It appears stochastic to someone who is only given the high level description, but it is still deterministic in the actual world. Given the Laplace's demon description of the system, there is no room for alternative possibilities. I think the author is only added the part I have bolded to try and deflect this. He is saying "we don't want the Laplace's demon description of the system, we just want the high level precis." Weirder still, he seems to suggest that getting the Laplace's demon is a realistic possibility, which obviously it's not. But the fact is it doesn't matter whether it's possible for a human to get the Laplace's demon description, or whether you actively pursue it or whatever - if your accept that it's there, as List seems to, then it fully determines the higher level phenomena and this idea about higher level indeterminacy is moot.

tpetrina 7y ago

> in the sense that you cannot easily predict next value Easily or _in principle_? Do not conflate our physical constraints with the actual mechanism behind the scene. Free will is not about our own ignorance or inability, it is the principal thing.

js8 7y ago
These are constraints from computational complexity. My point is the question "is it deterministic" is wrong without considering the level of detail you're looking at. Even in deterministic universe, a roll of dice is considered to be undeterministic, and this is good enough for casinos. If you're asking "in principle", then it might as well be unknowable because, as I pointed out, how we might observe the system to be (our model of it is deterministic or not) doesn't have to correspond at all whether it is actually deterministic or not at the lower level. So there always can be another level which can behave differently.