> On 12 Feb 2020, at 00:41, 'Brent Meeker' via Everything List > <[email protected]> wrote: > > > > On 2/11/2020 4:16 AM, Bruno Marchal 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. >> >> 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). > > What is a frequency operator?
I guess you have the book edited by DeWitt and Graham “The Many-World Interpretation of Quantum Mechanics”, Princeton 1973. See the paper by Graham “the measurement of relative frequency”, page 229. > Your WM thought experiment models a case in which the probabilities are > equal. It depends what you want to measure. The probability of WWWWWW is the same as WMWMWM, but the probability to have 2 W and 4 M is different, and will be given by the Binomial coefficients. > MWI seems implausible if it splits into two worlds when P(W)=P(M)=0.5 but > splits into a thousand worlds when P(W)=0.501 and P(M)=0.499. Yes, that one of the reason to understand that in all experience, there is an infinity-continuum of differentiation. That infinity is already there in arithmetic, at the meta and phenomenological level. Bruno > > Brent > >> >> 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] >> <mailto:[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 >> >> <https://groups.google.com/d/msgid/everything-list/A999D84A-F783-4381-9E7A-BF1CDE4A1F8C%40ulb.ac.be?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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/4eb571de-a01a-998d-3c4e-42169777f287%40verizon.net > > <https://groups.google.com/d/msgid/everything-list/4eb571de-a01a-998d-3c4e-42169777f287%40verizon.net?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/15F86914-6393-4E10-8A09-A23FB0CFF5E9%40ulb.ac.be.
