On Thu, 5 Mar 2020 at 08:54, Bruce Kellett <[email protected]> wrote:
> On Wed, Mar 4, 2020 at 11:01 PM Stathis Papaioannou <[email protected]> > wrote: > >> On Fri, 28 Feb 2020 at 08:40, Bruce Kellett <[email protected]> >> wrote: >> >>> 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.) >>> >> >> Probability derived from self-locating uncertainty is an idea independent >> of any particular physics. It is also independent of any theory of >> consciousness, since we can imagine a non-conscious observer reasoning in >> the same way. To some people it seems trivially obvious, to others it seems >> very strange. I don’t know if which group one falls into correlates with >> any other beliefs or attitudes. >> > > As I said, self-locating uncertainty is just another idea imposed on the > quantum formalism without any real theoretical foundation -- "it is just > imposed by fiat on a deterministic theory." If nothing else, this shows > that Carroll's claim that Everett is just "plain-vanilla" quantum > mechanics, without any additional assumptions, is a load of self-deluded > hogwash. > And as I said, probabilities derived from self-locating uncertainty is, for many people, trivially obvious, just a special case of frequentist inference. > -- Stathis Papaioannou -- 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/CAH%3D2ypXUah6wYyWJAf4fuJTR%2B6cKjUCj2pXLkoM745dowAm1xA%40mail.gmail.com.
