> On 11 Feb 2020, at 22:45, Bruce Kellett <[email protected]> wrote: > > On Tue, Feb 11, 2020 at 11:16 PM Bruno Marchal <[email protected] > <mailto:[email protected]>> wrote: > On 7 Feb 2020, at 12:07, Bruce Kellett <[email protected] > <mailto:[email protected]>> wrote: >> On Fri, Feb 7, 2020 at 9:54 PM Lawrence Crowell >> <[email protected] <mailto:[email protected]>> >> wrote: >> On Thursday, February 6, 2020 at 10:59:27 PM UTC-6, Bruce wrote: >> >> This argument from Kent completely destroys Everett's attempt to derive the >> Born rule from his many-worlds approach to quantum mechanics. In fact, it >> totally undermines most attempts to derive the Born rule from any branching >> theory, and undermines attempts to justify ignoring branches on which the >> Born rule weights are disconfirmed. In the many-worlds case, recall, all >> observers are aware that other observers with other data must exist, but >> each is led to construct a spurious measure of importance that favours their >> own observations against the others', and this leads to an obvious >> absurdity. In the one-world case, observers treat what actually happened as >> important, and ignore what didn't happen: this doesn't lead to the same >> difficulty. >> >> Bruce >> >> >> This appears to argue that observers in a branch are limited in their >> ability to take the results of their branch as a Bayesian prior. This >> limitation occurs for the coin flip case where some combinations have a high >> degree of structure. Say all heads or a repeated sequence of heads and tails >> with some structure, or apparent structure. For large N though these are a >> diminishing measure. >> >> I don't think you have fully come to terms with Kent's argument. How do you >> determine the measure on the observed outcomes? The argument that such >> 'outlier' sequences are of small measure fails at the first hurdle, because >> all sequences have equal measure -- all are equally likely. In fact, all >> occur with unit probability in MWI. > > Each individual sequence of head/tail would also occur with probability, in > the corresponding WM scenario, and in the coin tossing experience. > > OK. So what relevance does that comment have?
Of course I meant “probability” 1”. Sorry for the typo. The relevance is that this “probability one” is refuted from the first person view of the experimenter(s). > > In the MWI, what you describe is what has motivated the introduction of a > frequency operator, and that is the right thing to do in QM. > > What frequency operator? The trouble with any attempt to pretend that the > number of copies of any branch is related to the coefficient or weight of > that brranch in the superposition is that any such operator violates > unitarity. It would, in fact be nothing more than the von Neumann projection > operator in disguise. You are not going to rescue Everett in that way…… There are some critics possible on the use of a frequency operator, notably that it is really define “at the limit” of an finite number of experience, but that critics does not work with mechanism (used by Everett, who was unaware of the problem though, and use more the Gleason theorem to justify the measure. It is an alternative to that frequency operator). This comes from the fact that the first person is unable to detect the delays in the universal dovetailing (but of course this is also what lead to the mandatory derivation of the SWE itself from the statistics on all computations). > > > I think you might confuse the first person and the third person points of > view, in the WM-scenario and in the MWI (which is coherent with your > non-mechanist stance). > > That is your favourite rejoinder to any argument that you do not like. It is > just a meaningless straw man -- there is no relevant 1p/3p distinction in > operation here. How could that be possible? In all experience or experiment, you need to distinguish first and third person account, and even more so when self-multiplication and self-superposition are used. > From the 3p perspective, with unitary evolution (Everett), all sequences of > results occur with unit probability: It is the relative probabilities which count. The probability is not about being in W or in M, it is: knowing that you are in Helsinki, what it is the relative probability that you will feel yourself in W (res M). In the duplication, you know that you will survive (because you assume mechanism of course) and you know that P(coffee) = 1, because you have been promised coffee in both W and M, but you cannot write in your personal diary that the probability to be in W (res M) is one. You can predict that it will be a unique city, though, because in both cities, the duplicated person will see only one city. > the sequences do not depend on the weights, The consciousness existence in the sequence does not depend on the weight, but the probability of the consciousness continuation does depends on the weight. > so the sequences are the same whatever the initial state. From the 1p > perspective, an individual sees one of these sequences when he performs > repeated trials. The probabilities that he might infer from the data cannot > reflect the branch weights -- because the sequences are independent of the > branch weights. The theory has failed. Yet, after 100 iteration of the WM-duplication, only one guy say that his prediction that he will got the binary digits of PI, and 2^100 - 1 will say “I was wrong”. With mechanism, this explains the behaviour of light crossing an half-silvered mirror. Bruno > > Bruce > > -- > 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 [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/CAFxXSLT9_t0g53ByCkMQR%3DWS3jADEW_mwmrrWKd_zz_0zWoRAg%40mail.gmail.com > > <https://groups.google.com/d/msgid/everything-list/CAFxXSLT9_t0g53ByCkMQR%3DWS3jADEW_mwmrrWKd_zz_0zWoRAg%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/908AC454-A07A-428A-B06D-2180B4C0C92D%40ulb.ac.be.
