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. 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/CAFxXSLRKUmzW3Db2kze0RHOKbTYkna_5gWnmxi3onB_KhFmUcw%40mail.gmail.com.
