> On 18 Feb 2021, at 04:39, Bruce Kellett <[email protected]> wrote: > > On Thu, Feb 18, 2021 at 2:21 PM 'Brent Meeker' via Everything List > <[email protected] <mailto:[email protected]>> > wrote: > On 2/17/2021 6:46 PM, Bruce Kellett wrote: >> On Thu, Feb 18, 2021 at 1:05 PM 'Brent Meeker' via Everything List >> <[email protected] <mailto:[email protected]>> >> wrote: >> On 2/17/2021 4:29 PM, Bruce Kellett wrote: >>> Thus previous experience is no guide to the future in MWI. I know this is >>> true also in ordinary classical probability theory, but the difference is >>> that in MWI, one or more of your successors is bound to see the atypical >>> sequences -- that is not guaranteed in classical probability theory. It >>> *might* happen, but it is not *bound to* happen. This difference is >>> important. >> >> I don't think it's even relevant. It isn't "bound to happen" to you. It's >> just a possibility for you, just as it is in the Kolmogorov sample space. >> >> >> This is the problem with personal identity in many worlds -- the copies are >> all *you*, so your comment is without force. You are sneaking in the >> collapse that Sabine mentions; or you are making a dualist assumption -- >> only one of the copies is *really you*. > > I don't think so. Every copy post-test is some copy of you pre-test. The > Everett explicitly writes the post-test wave function with all the you's in > it. I don't see that as any more problematic than referring to possible > you's pre-test. In any probabilistic theory only one possibility is realized > > > That is where you keep slipping in the implicit collapse (or dualist identity > hypothesis). In MWI it is just not the case that only one possibility is > realized.
It is not the case that only one possibility is realised, in the 3p-view. But as the WM illustrates in a simpler (non quantum) setting, despite it is true that after the split “you” are both in Washington and Moscow, it is plain obvious that the two copies will feel differently, and will feel to see only one city. That is predictable using just mechanism, and the fact that they have no telepathic communication. The one in W will say “I see only Washington” and the one in Moscow will say “I see only Moscow”, and, as they bet on mechanism, they knew this in advance. This indeterminacy is provable, from the mechanist simple assumption. > > > ...that doesn't mean we have to assume there was some realism-spirit that got > passed to it. > > > If you don't like dualism, then you are left with an implicit collapse > hypothesis. There are no other options in MWI. You are left with a phenomenological collapse, entirely explainable in a monist theory of mind. Now if that theory is mechanism, the indeterminacy can no more be related to any particular sort of computation (selected by some personal or impersonal ontology), making obligatory to extract the wave itself from the measure on all computations, and this is confirmed by what the universal machine already deduce in arithmetic: there is just no evidence for any needed ontological commitment, as we infer already the MWI from observation, after having it deduced from simple mechanism. And then, thanks to incompleteness we get different mathematics for the qualia and the quanta, where the naturalist are known to not address this question, if not abuse of identification which simply cannot work (unless abandoned,dong mechanism). I think that you are just eliminating the first person discourse. You look at all the diaries, without reading any particular one. Bruno > > >> >> <........> >>> >>> Yes. I think that the idea that Bob has been pursuing is a definite >>> non-starter. Carroll is smart enough to see this, even though he does want >>> to finally reduce probability to branch counting. The real trouble I see >>> with Sean's approach is that he has to call on Born rule insights to know >>> how many additional branches to manufacture. His approach is irreducibly >>> circular. >> >> But then he could just postulate the Born rule as the way to partition, or >> create, branches and it would work; which is what Sabine says. And that >> tells me that the Hemmo and Pitkowsky objection is wrong. >> >> >> That is what Carroll and Bob are doing. But that rather defeats the purpose >> of deriving the Born rule from the Schrodinger equation alone. All such >> arguments are inherently circular. > > I agree with that. Do you agree that it would work to simply add the Born > rule to MWI as a postulate? > > > I have difficulty seeing how that could work. For the Born rule to work, the > dynamics have to 'see' the amplitudes rather than just the eigenstate basis > vectors. But this does not happen in Everett. The set of histories arising in > N repetitions of the spin measurement is the same for any two-component > initial state -- there is no differentiation of the histories according to > the Born probabilities. > > You have attempted to remedy this by assuming that the number of branches on > each trial splits in the Born rule ratios. But this is inconsistent with > unitary evolution and the MWI. You might be able to construct a many worlds > theory that has the Born rule as an independent postulate -- but the > resultant theory will not be quantum mechanics as we know it. I doubt that it > can even be unitary. > > 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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/CAFxXSLSgYLYjRDBnhHUs2Bd1%2Bdk0Cyq1RLobMS9BLZ9vajt3WA%40mail.gmail.com > > <https://groups.google.com/d/msgid/everything-list/CAFxXSLSgYLYjRDBnhHUs2Bd1%2Bdk0Cyq1RLobMS9BLZ9vajt3WA%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- 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/6B68F18C-1637-4B5C-B16D-F0FD17CEA44F%40ulb.ac.be.
