On Sat, Feb 8, 2020 at 5:39 PM 'Brent Meeker' via Everything List < [email protected]> wrote:
> On 2/7/2020 9:54 PM, Bruce Kellett wrote: > > On Sat, Feb 8, 2020 at 4:41 PM 'Brent Meeker' via Everything List < > [email protected]> wrote: > >> On 2/7/2020 8:14 PM, Bruce Kellett wrote: >> >> On Sat, Feb 8, 2020 at 1:26 PM 'Brent Meeker' via Everything List < >> [email protected]> wrote: >> >>> On 2/7/2020 5:57 PM, Bruce Kellett wrote: >>> >>> There is nothing that picks out one particular set of paths as preferred >>> in the many-worlds situation. >>> >>> >>> Sure you can. For example you can pick out the set of paths whose >>> statistics are within some bounds of the mean. >>> >> >> Assuming you know what the 'mean' is absent any experiment. >> >> >> The mean is estimated by the average of the experimental values. >> > > > In other words, you use the data to infer probabilities. But the same data > occur whatever the probabilities, so your backward inference to the > probabilities is meaningless. > >> Otherwise you are just cherry picking data to support your arbitrary >> theory. >> >>> One can only get that in a stochastic one-world model. >>> >>> >>> All paths occur in a stochastic one-world model too. >>> >> >> No they don't. They are possible, perhaps, but they do not necessarily >> occur. >> >> >> They don't *necessarily* occur. But they probabilistic occur. >> > > It means they occur with high probability given enough instances of the > experiment. So I don't see why you attach great significance to all > possibilities occurring in MWI. > The problem here is "what constitutes enough instances of the experiment?". In MWI, all sequences occur for ever run of several trials. In a single-world theory, there are some sequences that will have such a low probability that you could wait till the end of time and never see them. What on earth does that mean? > > If the probability is very low, then the improbable sequences of results > need not occur even if you repeat the experiment 'till the heat death of > the universe. In MWI the low weight sequences necessarily occur in every > run of the experiments. Do you not see the difference? > > > But the improbable sequences will occur in the same proportion in both > scenarios. > No they won't. Because we do do an infinite number of repeats of any experiment. But all possible sequences occur on every run in the Many-worlds scenario. That does not seem like the same proportion in both scenarios. Otherwise it wouldn't be a stochastic model. So it seems that all you >> objections to MWI apply equally. >> > > > Get a grip, Brent. > >> >> The only difference is that some probability measure is assumed as part >>> of the model. >>> >> >> And this gives one a principled reason for ignoring the paths that are >> not observed. >> >> >> Why not ignore them because they are not observed? That's a principled >> reason. >> > > That is a one-world theory. And I agree that that is the way to go. > > Low probability has an independent meaning in the one-world case, so one >> is unlikely to observe a low probability set of results. >> >> >> One is unlikely to observe a result that is realized in only a small >> fraction of the MW branches. >> > > Why? One does not choose one's results at random from the set of all > possible results. > > > The theory is that which experience "you" have is determined by making a > copy of you for each result and one of them, at random, is the "you" who > has the experience. So it is effectively a random sample from the possible > results. > It is an indexical theory. The problem is that in MWI there will always be observers who see the sequences that are improbable according to the Born rule. This is not the case in the single-world theory. There is no random sampling from all possibilities in the single-world theory. In MWI there is always an observer who gets every possible set of results. > Why ignore those unfortunates who get rest inconsistent with your pet > theory? > > > Because they are relatively few in number and hence unlikely to be the > "you" who gets the result. > Unlikely to be you? OK, but what about the poor unfortunate who did get the anomalous results. You choose cavalierly to ignore him . But the fact that they might be few in number in the multiverse does not diminish their importance to themselves, even if not to anyone else. I agree that MWI fails to derive the Born rule. But I don't agree that >> it is inconsistent with it, given the version of MWI that postulates many >> branches...not just one per possible outcome. >> > > The point is that MWI is inconsistent with experience. There will always > be observers who get results inconsistent with the Born rule. > > > Why do you think you can't get a result inconsistent with the Born rule in > one world. > I don't think that. It is just that it is very unlikely -- of low probability. It has probability one with MWI. What do you mean by "inconsistent". The results are probabilistic so they > will have degrees of consistency and inconsistency with the Born > rule...just as there is a spread of results in MWI. > There are no probabilities in MWI. The probability of getting an anomalous set of results for a sequence of measurements of z-spin up for repeated measurement on x-spin up particles is calculable in quantum mechanics. But the result is different in MWI since the probability for any sequence whatsoever is one. And we cannot ensure that we are not such observers. So how can we claim > that our theory is confirmed by the data? The data are consistent with all > possible theories -- or none at all. > > > But it's not all or nothing. It's statistics. > So if we see anomalous results at the LHC we continue gathering data to ascertain whether it is a real effect, or merely a statistical anomaly. This possibility is not available in MWI (even though people pretend that it is). MWI cannot explain the consistency of the statistical results we observe. 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]. 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