On Fri, Sep 13, 2024 at 6:12 PM Stathis Papaioannou <[email protected]> wrote:
> On Fri, 13 Sept 2024 at 17:30, Bruce Kellett <[email protected]> > wrote: > >> On Fri, Sep 13, 2024 at 5:23 PM Stathis Papaioannou <[email protected]> >> wrote: >> >>> On Fri, 13 Sept 2024 at 15:08, Bruce Kellett <[email protected]> >>> wrote: >>> >>>> On Fri, Sep 13, 2024 at 1:07 PM Liz R <[email protected]> wrote: >>>>>> >>>>>> I don't think that works. The idea often put forward is something >>>>>> along the lines of self-locating uncertainty -- out of all the branches, >>>>>> which one am I on? But that is only apparent randomness, and to get such >>>>>> an >>>>>> idea to work, you need to be able to make a random choice between >>>>>> branches. >>>>>> Such randomness will be intrinsic in that It doesn't come from anywhere >>>>>> else (it is not already part of the theory). So in order to generate such >>>>>> apparent randomness you actually need an independent source of intrinsic >>>>>> randomness (to be able to make your self-locating choice.) >>>>>> >>>>> >>>>> The intrinsic randomness arises from the fact that it is impossible to >>>>> predict which branch you will end up in, even for an omniscient being. >>>>> >>>> >>>> That is just a restatement of the traditional measurement problem. >>>> Self-locating uncertainty is not intrinsic randomness. What is it that >>>> selects which branch you are actually on? You need some means of random >>>> selection which is not included in the underlying theory. You have to add, >>>> by hand, some additional principle of randomness, such as the Born Rule. >>>> >>> >>> Nothing selects which branch you will be on, since with certainty a >>> version of you will end up in each branch. If the omniscient being predicts >>> that you will end up in branch A, the prediction is wrong for the version >>> of you in branch B, and if the omniscient being predicts that you will end >>> up in branch B the prediction is wrong for the version of you in branch A. >>> It is logically impossible to make an accurate prediction. >>> >> >> It is unfortunate, therefore, that all real experiments result in just >> one answer, which is the nub of the measurement problem. Which answer is >> unpredictable, but that does not mean that there can be some omniscient >> being that can predict your result. It is a matter of an intrinsic >> probability -- *viz*. the Born Rule. >> > > The branching makes the outcome fundamentally unpredictable, which is what > randomness is. > That is not randomness. Unpredictability might be a consequence of randomness, but they are not the same thing. It results from the branching and nothing else. It is not specific to QM or > MWI: it results from any process where the observer branches. > The problem with this approach is that it takes no account of probability. I can arrange things so that the probability of a particular result is, say, 0.7, and this can be verified with repeated experiments. If it is just a matter of the branching, then the probability is unity on every trial. So unpredictability and/or branching, in themselves, cannot account for probability. 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/CAFxXSLR71PjO_GSyZBuSAWUAR2553Wo8rvHc2aDGC9_8joMkHw%40mail.gmail.com.
