On Fri, Jun 21, 2019 at 2:35 PM 'Brent Meeker' via Everything List < [email protected]> wrote:
> On 6/20/2019 9:09 PM, Bruce Kellett wrote: > > On Fri, Jun 21, 2019 at 1:19 PM 'Brent Meeker' via Everything List < > [email protected]> wrote: > >> On 6/20/2019 5:56 PM, Bruce Kellett wrote: >> >> From: Bruno Marchal <[email protected]> >> >> >> I don’t think your refutation of step 3 has been understood by anyone. >> >> If someone else want to argue that there is no indeterminacy in the self >> duplication experience, he is welcome. >> >> >> I think that some might challenge your interpretation of this >> indeterminacy. This might not be exactly JC's objection to step 3, but, to >> my mind, it is a serious difficulty in its own right. >> >> This comes from a recent podcast of a conversation between Sean Carroll >> and David Albert: >> >> https://www.youtube.com/watch?v=AglOFx6eySE >> >> This is a long discussion, and the relevant parts of Albert's objections >> to MWI and self-locating uncertainty come towards the end. >> >> The essence of Albert's point is that in the duplication case, you ask >> "What is the probability that you will find yourself in Moscow (resp. >> Washington)?" Putting aside objections to the non-specificity of the >> pronoun 'you', I think your answer is that the probabilities are 0.5 for >> either city. Albert points out that to reach this conclusion, you use some >> principle of indifference, or point to some symmetry between the possible >> outcomes. Using this symmetry, you claim that the probabilities must be >> equal, hence 0.5 for each city. Now, says Albert, there is another solution >> that also respects all the symmetries involved, viz., "I have not idea what >> the probability is." >> >> You can then easily argue that this is a better solution. Because the >> probability 0.5 is not written in the physics of the situation -- it comes >> entirely from the classical principle of indifference. So Albert asks how >> you are going to verify this probability experimentally -- as a large N >> limit, or something similar. So you repeat the duplication N times on your >> participants. i.e. after the original duplication you transport the >> subjects back to Helsinki and repeat the duplication to Washington and >> Moscow. You end up with 2^N copies, each of which has a record of the N >> cities they found themselves in after each duplication. You now ask each of >> them their best estimate of the probabilities for W or M on each >> duplication. Of course, you then get all possible answers, from 1/N for M >> to 1/N for W. Since, withprobaility one, the will always be someone who >> found himself in M each time, and similarly, someone who found himself in W >> each time. Plus all other 2^ possible combinations of results. >> >> >> But most participants will say they were in Washington approximately N/2 >> times and Moscow N/2 times, in accordance with a binomial distribution. >> > > But I am not "most participants". I am just me, only one of me. I could > easily be the guy who sees 100% Moscow. > > > Not "easily" since seeing only Moscow has probability 1/2^N. And it's > not just you I need to convince. I need to write a paper showing that my > P(M)=P(W)=0.5 theory is supported and the statistics reported by the > participants do exactly that. > As Bruno might say, that is to take the 3p view of things. I am concerned about the 1p view, where this survey of all participants is not possible. The point, of course, is to relate this to the many worlds interpretation of QM. There one does not have the option of surveying outcomes over all branches in order to reach one's conclusions about probabilities. Put another way, if MWI is true, why do we not regularly see substantial deviations from the Born Rule probabilities? After all, repetitions of the relevant interactions are happening all the time: and not just in our controlled experiments. How can there be such things as objective probabilities in the MWI scenario? How can we use experimental evidence to support theories when we do not know whether our observer probabilities are representative or not? 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/CAFxXSLSV4OPkXpj4V_7a3k2i%2BqjHryfCDr2uPEzE-3QyHbF1%2Bg%40mail.gmail.com.
