I agree with most of the things you are saying here. I am not sure I agree about the cosmological horizon; it seems like you could derive this from special relativity, but in any case this is a minor point. I don’t know enough physics to confirm the thing you said about gravity and collapse.
In any case it seems you are currently saying “no collapse at intermediate scales is a good hypothesis and maybe wrong for this specific reason” whereas initially you were saying “interpretations [of quantum mechanics] by definition make no difference” and “I don’t know what untestable musings can say about the nature of reality”, and these statements seem to be in tension (as the question of whether collapse happens at intermediate scales depends on what are currently called “interpretations of quantum mechanics”, and is currently untestable); do you still agree with your original statements?
Yes, you could derive the horizon stuff from special relativity, but to construct an asymptotically de Sitter spacetime you need general relativity. Anyway, that wasn’t the original issue. “no collapse at intermediate scales is a good hypothesis and maybe wrong for this specific reason” is one possibility, the likelihood of which is currently hard to evaluate, as it extrapolates quantum mechanics far beyond the domain where it had been tested (Zeilinger’s bucky ball double slit experiments). The nature of the apparent collapse is a huge open problem, with decoherence and Zurek’s quantum Darwinism giving some hints at why certain states survive and others don’t, and pretending that MWI somehow dissolves the issue, the way Eliezer tells the tale, is a bit of a delusion. Anyway, MWI does not make any predictions, since it simply tells you that the feeling of being in a single world is an illusion, without going into the details of how to resolve the Wigner’s friend and similar paradoxes. See Scott Aaronson’s lecture 12 on the topic for more discussion.
I agree with most of the things you are saying here. I am not sure I agree about the cosmological horizon; it seems like you could derive this from special relativity, but in any case this is a minor point. I don’t know enough physics to confirm the thing you said about gravity and collapse.
In any case it seems you are currently saying “no collapse at intermediate scales is a good hypothesis and maybe wrong for this specific reason” whereas initially you were saying “interpretations [of quantum mechanics] by definition make no difference” and “I don’t know what untestable musings can say about the nature of reality”, and these statements seem to be in tension (as the question of whether collapse happens at intermediate scales depends on what are currently called “interpretations of quantum mechanics”, and is currently untestable); do you still agree with your original statements?
Yes, you could derive the horizon stuff from special relativity, but to construct an asymptotically de Sitter spacetime you need general relativity. Anyway, that wasn’t the original issue. “no collapse at intermediate scales is a good hypothesis and maybe wrong for this specific reason” is one possibility, the likelihood of which is currently hard to evaluate, as it extrapolates quantum mechanics far beyond the domain where it had been tested (Zeilinger’s bucky ball double slit experiments). The nature of the apparent collapse is a huge open problem, with decoherence and Zurek’s quantum Darwinism giving some hints at why certain states survive and others don’t, and pretending that MWI somehow dissolves the issue, the way Eliezer tells the tale, is a bit of a delusion. Anyway, MWI does not make any predictions, since it simply tells you that the feeling of being in a single world is an illusion, without going into the details of how to resolve the Wigner’s friend and similar paradoxes. See Scott Aaronson’s lecture 12 on the topic for more discussion.