Thanks for the comments! On Wednesday, April 13, 2022 at 8:55:48 PM UTC+3 meeke...@gmail.com (Brent) wrote:

Physics doesn't care about "rationally justified", only about empirically > justified. I admit that I have carried the subject to philosophy of physics, but only because this kind of subject cannot be addressed with just experiments. On the other hand, do you admit that your comment needs qualifications? You cannot possibly mean that we just obtain the Born Rule from experiments, and that this is all we care about. Did Einstein make any sense, complaining about who plays dice during a measurement? What was the point of attempts to introduce hidden variables, even at the cost of non-locality? What is the point of MWI, then? I suppose that you are a careful thinker, and if you object to MWI it would be on some rational grounds. Both your examples suffer from choosing the simplest case where symmetry > can be invoked. So that you would not be distracted from the basic issue: do you agree with always averaging over future selves (Deutsch) or do you take it for granted that the theory provides probability (Zurek and others)? Or none of the above? Correct me if I am wrong, but I gather that your responce is "who cares", or "po-tah-toes, pot-eight-os". Once you've assumed the Hilbert space structure of QM, then Gleason's > theorem essentially forces the Born rule (correct me if I'm wrong, but I > think the theorem has been extended to the two-dimensional case). I shall respectfully correct you, but not on the question you ask, because I cannot remember now, and I admit that I do not care to look it up (but I explain why). Gleason's theorem also requires the assumption of randomisation (God plays dice) and the assumption of non-contextuality of measurements. The reason I do not care about it any more is that I do not favour these two assumptions (especially the first one). I think the problem is that MWI (but not Everett) assume all outcomes are > equally realized. So how does a probability become assigned to them, what > does it mean. I agree, and I am glad you are critical on this point. I am intrigued, though, by the caveat "but not Everett": can you explain, please? We're told it's the probability of finding ourself in a particular > world...but that seems very much like "collapse of the wave-function". It > introduces the same problems of exactly when and where does it happen; with > only the advantage that consciousness is not understood in detail so the > mystery can be push off. I emphasise that I have no comment on the above, because I do not endorse probability strictly speaking but only on an "as-if" basis. (I agree with Deutsch on this narrow point -- Physics doesn't care, really?) Decoherence has gone part way in solving the when/where/what basis > questions, but only part way. > I guess you refer to the theoretical possibility of the environment occasionally failing to "decohere" the state. Here is one of the approximations that are required in the translation from objective, deterministic QM (without collapse) to the application of QM in the world of experience (with apparent collapse). Surely this approximation must be scrutinised, I agree. George K. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/de126bb1-3528-4f0a-9c2e-9a1cb0350644n%40googlegroups.com.