> On 7 Feb 2020, at 12:07, Bruce Kellett <[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. 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. 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). Bruno > > Bruce > > > An observer might see their branch as having sufficient randomness to be a > Bayesian prior, but to derive a full theory these outlier branches with the > appearance of structure have to be eliminated. This is not a devastating blow > to MWI, but it is a limitation on its explanatory power. Of course with > statistical physics we have these logarithms and the rest and such slop tends > to be "washed out" for large enough sample space. > > No matter how hard we try it is tough to make this all epistemic, say > Bayesian etc, or ontological with frequentist statistics. > > LC > > -- > 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/CAFxXSLRz%3D6MzUV13uBDrKrH%2BAO_RhizyyCaT1wcdpF6ctLxBUA%40mail.gmail.com > > <https://groups.google.com/d/msgid/everything-list/CAFxXSLRz%3D6MzUV13uBDrKrH%2BAO_RhizyyCaT1wcdpF6ctLxBUA%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/A999D84A-F783-4381-9E7A-BF1CDE4A1F8C%40ulb.ac.be.
