Stathis Papaioannou
On Fri, Sep 13, 2024 at 19:31 Bruce Kellett <[email protected]> wrote: > On Fri, Sep 13, 2024 at 6:45 PM Stathis Papaioannou <[email protected]> > wrote: > >> On Fri, Sep 13, 2024 at 18:15 Quentin Anciaux <[email protected]> wrote: >> >>> Le ven. 13 sept. 2024, 10:12, Stathis Papaioannou <[email protected]> >>> a écrit : >>> >>>> 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. 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 thing is to recover the born rules, some frequency must be in play, >>> some things are more likely than other, if you had to make a bet, it's >>> important and you wouldn't bet every outcome is equally likely. >>> >> >> Isn’t that separate from the question of whether the randomness an >> observer sees in MWI is truly random? >> > > No. Randomness includes the notion of a probability distribution. > If the probability of an event is 0 or 1 it is determined, otherwise it is random. > -- 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%3D2ypV5q%2BrMSsKNgJUgM8ZMamU0nh%2Be9EB5SaWK6jyK1Gyw%2Bg%40mail.gmail.com.
