On Fri, Feb 28, 2020 at 4:21 AM 'Brent Meeker' via Everything List < [email protected]> wrote:
> On 2/27/2020 3:45 AM, Bruce Kellett wrote: > > > That is probably what all this argument is actually about -- the maths > show that there are no probabilities. Because there are no unique > probabilities in the classical duplication case, the concept of probability > has been shown to be inadmissible in the deterministic (Everettian) quantum > case. The appeal by people like Deutsch and Wallace to betting quotients, > or quantum credibility measures, are just ways of forcing a probabilistic > interpretation on to quantum mechanics by hand -- they are not derivations > of probability from within the deterministic theory. There are no > probabilities in the deterministic theory, even from the 1p perspective, > because the data are consistent with any prior assignment of a probability > measure. > > > The probability enters from the self-location uncertainty; which is other > terms is saying: Assume each branch has the same probability (or some > weighting) for you being in that branch. Then that is the probability that > you have observed the sequence of events that define that branch. > I think that is Sean Carroll's approach. I am uncertain as to whether this really works or not. The concept of a 'weight' or 'thickness' for each branch is difficult to reconcile with the first-person experience of probability: which is obtained within the branch, so is independent of any overall 'weight'. But that aside, self-locating uncertainty is just another idea imposed on quantum mechanics and, like decision-theoretic ideas, it is without theoretical foundation -- it is just imposed by fiat on a deterministic theory. It makes probability a subjective notion imposed on a theory that is supposedly objective: there is an objective probability that a radioactive nucleus will decay in a certain time period -- independent of our subjective impressions, or self-location. (I can develop this thought further, if required, but I think it shows Sean's approach to fail.) 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLQs%2BPekZ_sX5b3b4peSumyKfqaHyK78tE2Sjo%3DENOT7jQ%40mail.gmail.com.
