Taking (2) to its logical conclusion seems to imply that we live in a deterministic block universe,
That was not implied by (2) as stated, and isn’t implied by physics in general. Both the block universe and determinism are open questions (and not equivalent to each other).
One of the chief problems here is that physics, so far as we can tell, is entirely local.
[emph. added]
Nope. What is specifically ruled out by test’s of Bell’s inequalities is the conjunction of (local, deterministic). The one thing we know is that the two things you just asserted are not both true. What we don’t know is which is false.
What is specifically ruled out by test’s of Bell’s inequalities is the conjunction of (local, deterministic). The one thing we know is that the two things you just asserted are not both true. What we don’t know is which is false.
I think you’re nitpicking here. While we don’t know the fundamental laws of the universe with 100% confidence, I would suggest that based on what we do know, they are extremely likely to be local and non-deterministic (as opposed to nonlocal hidden variables). Quantum field theory (QFT) is in that category, and adding general relativity doesn’t change anything except in unusual extreme circumstances (e.g. microscopic black holes, or the Big Bang—where the two can’t be sensibly combined). String theory doesn’t really have a meaningful notion of locality at very small scales (Planck length, Planck time), but at larger scales in normal circumstances it approaches QFT + classical general relativity, which again is local and non-deterministic. (So yes, probably our everyday human interactions have nonlocality at a part-per-googolplex level or whatever, related to quantum fluctuations of the geometry of space itself, but it’s hard to imagine that this would matter for anything.)
(By non-deterministic I just mean that the Born rule involves true randomness. In Copenhagen interpretation you say that collapse is a random process. In many-worlds you would say that the laws of physics are deterministic but the quasi-anthropic question “what branch of the wavefunction will I happen to find myself in?” has a truly random answer. Either way is fine; it doesn’t matter for this comment.)
In many-worlds you would say that the laws of physics are deterministic
The only thing non-deterministic in QM is the Born rule, which isn’t part of a MWI block universe formulation. (You need a source of randomness to specify where “you” will end up in the future evolution of the universe, but not to specify all paths you might end up in.)
That was not implied by (2) as stated, and isn’t implied by physics in general. Both the block universe and determinism are open questions (and not equivalent to each other).
[emph. added]
Nope. What is specifically ruled out by test’s of Bell’s inequalities is the conjunction of (local, deterministic). The one thing we know is that the two things you just asserted are not both true. What we don’t know is which is false.
Actually the superdeterminism models allow for both to be true. There is a different assumption that breaks.
I think you’re nitpicking here. While we don’t know the fundamental laws of the universe with 100% confidence, I would suggest that based on what we do know, they are extremely likely to be local and non-deterministic (as opposed to nonlocal hidden variables). Quantum field theory (QFT) is in that category, and adding general relativity doesn’t change anything except in unusual extreme circumstances (e.g. microscopic black holes, or the Big Bang—where the two can’t be sensibly combined). String theory doesn’t really have a meaningful notion of locality at very small scales (Planck length, Planck time), but at larger scales in normal circumstances it approaches QFT + classical general relativity, which again is local and non-deterministic. (So yes, probably our everyday human interactions have nonlocality at a part-per-googolplex level or whatever, related to quantum fluctuations of the geometry of space itself, but it’s hard to imagine that this would matter for anything.)
(By non-deterministic I just mean that the Born rule involves true randomness. In Copenhagen interpretation you say that collapse is a random process. In many-worlds you would say that the laws of physics are deterministic but the quasi-anthropic question “what branch of the wavefunction will I happen to find myself in?” has a truly random answer. Either way is fine; it doesn’t matter for this comment.)
Well, I wasn’t nitpicking you. Friedenbach was assserting locality+determinism. You are asserting locality+nondeterminism, which is OK.
FWIW I was asserting this:
The only thing non-deterministic in QM is the Born rule, which isn’t part of a MWI block universe formulation. (You need a source of randomness to specify where “you” will end up in the future evolution of the universe, but not to specify all paths you might end up in.)