On Sat, Feb 8, 2020 at 12:28 PM Lawrence Crowell < [email protected]> wrote:
> On Friday, February 7, 2020 at 7:10:54 PM UTC-6, Bruce wrote: >> >> On Sat, Feb 8, 2020 at 11:51 AM Lawrence Crowell < >> [email protected]> wrote: >> >>> On Friday, February 7, 2020 at 6:16:45 PM UTC-6, Bruce wrote: >>>> >>>> On Sat, Feb 8, 2020 at 4:33 AM Stathis Papaioannou <[email protected]> >>>> wrote: >>>> >>>>> On Fri, 7 Feb 2020 at 15:59, Bruce Kellett <[email protected]> >>>>> wrote: >>>>> >>>>>> >>>>>> This argument from Kent completely destroys Everett's attempt to >>>>>> derive the Born rule from his many-worlds approach to quantum mechanics. >>>>>> In >>>>>> fact, it totally undermines most attempts to derive the Born rule from >>>>>> any >>>>>> branching theory, and undermines attempts to justify ignoring branches on >>>>>> which the Born rule weights are disconfirmed. In the many-worlds case, >>>>>> recall, all observers are aware that other observers with other data must >>>>>> exist, but each is led to construct a spurious measure of importance that >>>>>> favours their own observations against the others', and this leads to an >>>>>> obvious absurdity. In the one-world case, observers treat what actually >>>>>> happened as important, and ignore what didn't happen: this doesn't lead >>>>>> to >>>>>> the same difficulty. >>>>>> >>>>> >>> Carroll and Sebens worked a paper a year ago illustrating how MWI was >>> consistent with Born rule. They did have to restrict paths or states that >>> were too far removed from being a good Bayeisan prior, so it is a bit >>> loose. However, it was not bad. >>> >> >> Not bad!!!! I suppose if you feel justified in just throwing away >> anything that does not suit your favourite theory, then you can get away >> with anything. It is the fact that these 'worlds' that are far removed >> from what one wants to see cannot just be "thrown away" that destroys MWI. >> Given that the probability of particular outcomes no longer has meaning >> when all outcomes necessarily occur, one cannot use any observed data to >> justify any theory about the probabilities. All theories are just as good, >> or just as bad. Consequently, assuming probabilities for particular >> outcomes no longer makes any sense. >> >> > The set of amplitudes or paths thrown away is a small measure. The bounds > are not entirely certain, but they are comparatively small. > The problem is to justify that the paths thrown away do, in fact, have small measure. The proof given by Kent shows that, whatever result you obtain, you can argue that contrary results have "small measure", and can be thrown away. There is nothing that picks out one particular set of paths as preferred in the many-worlds situation. One can only get that in a stochastic one-world model. 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/CAFxXSLS0HPUp3vfn4-ABF54mypbM9m_Ogmq%2BGDm3TwheOM0Mnw%40mail.gmail.com.
