Le mar. 18 févr. 2025, 00:39, Bruce Kellett <[email protected]> a écrit :
> On Tue, Feb 18, 2025 at 10:34 AM Quentin Anciaux <[email protected]> > wrote: > >> Le mar. 18 févr. 2025, 00:32, Bruce Kellett <[email protected]> a >> écrit : >> >>> On Tue, Feb 18, 2025 at 10:13 AM Quentin Anciaux <[email protected]> >>> wrote: >>> >>>> >>>> >>>> Le mar. 18 févr. 2025, 00:05, Bruce Kellett <[email protected]> a >>>> écrit : >>>> >>>>> On Tue, Feb 18, 2025 at 9:51 AM Quentin Anciaux <[email protected]> >>>>> wrote: >>>>> >>>>>> >>>>>> If you assign probability to horse X winning, you are describing >>>>>> uncertainty before the race is run, which is exactly the point. In >>>>>> standard >>>>>> probability, that uncertainty is about a single outcome being realized. >>>>>> In >>>>>> MWI, it’s about which branch an observer will find themselves in. >>>>>> >>>>> >>>>> And how many branches is that? It is just about a single outcome being >>>>> realized. Other possibilities are not realized. Same as with probability >>>>> -- >>>>> One thing happens, others don't. >>>>> >>>> >>>> In a single-history universe, unrealized possibilities are nothing more >>>> than fiction, they never happen, never will, and have no causal impact on >>>> reality. Why invoke entities that don’t exist and never will to explain the >>>> one outcome that does? That’s not an explanation, it’s just storytelling. >>>> >>>> >>>>> The key question isn’t whether probability exists before measurement, >>>>>> it’s why the observer should expect the Born rule to govern the >>>>>> distribution of experiences. If you dismiss self-locating uncertainty, >>>>>> then >>>>>> what mechanism in a purely unitary framework explains why we don’t see >>>>>> uniform distributions or some other weighting instead of Born’s rule? >>>>>> >>>>> >>>>> Why do you expect to see outcomes conforming to the Born probabilities? >>>>> >>>> >>>> Because experiments consistently confirm the Born probabilities. The >>>> question isn’t whether they hold, it’s why they hold in a purely unitary >>>> framework. In a single-world view, you assume the Born rule as a >>>> fundamental postulate. In MWI, it should emerge naturally, but without a >>>> clear derivation, it remains an open problem >>>> >>>> >>>>> In a single-world framework, the supposed ensemble of possible >>>>>> outcomes is purely imaginary, it never happens, it never will, and it has >>>>>> no more reality than a work of fiction. Treating these unrealized >>>>>> possibilities as if they have explanatory power is just storytelling, >>>>>> not a >>>>>> real mechanism. >>>>>> >>>>> >>>>> You are obsessed with 'mechanisms'. This is quantum mechanics, not >>>>> 19th century rods-and-wires stuff. What is the "mechanism" of gravity? >>>>> With >>>>> Newton we can reasonably say *Hypotheses non fingo!* >>>>> >>>> >>>> Physics has always sought deeper explanations beyond just stating “this >>>> is how things happen.” Newton could say hypotheses non fingo because his >>>> equations worked without additional assumptions. But if unitary evolution >>>> is all there is, why should probability emerge at all, and why should it >>>> follow Born’s rule? Dismissing this as an unnecessary question is just >>>> assuming what needs to be explained. >>>> >>> >>> Anyone who has experience of dealing with small children, knows that >>> there can always be an endless sequence of "why?" questions. The trouble is >>> that such sequences always end up with something like "why am I who I am >>> and not someone else?" Some questions simply have no answers. >>> >>> As I have pointed out, MWI is inconsistent with the Born rule, so >>> looking for an explanation of the Born rule in MWI is rather silly. >>> >> >> You did not, you're just assuming what you want to prove. >> > > As I recall it, we called the discussion off because you couldn't see that > the 2^N binary sequences from N trials of a measurement on |psi> = a|0> + > b|1> sre independent of the amplitudes a and b. So the sequences, which > give probability estimates, do not agree with the Born probabilities a^2 > and b^2. > > Bruce > Bruce, You didn’t prove that MWI is inconsistent with the Born rule, you assumed it by asserting that all 2^N sequences contribute equally, which is not how MWI works. The amplitude coefficients do matter, they determine the measure of each sequence, which affects the relative frequency of observed outcomes. Your argument rests on the assumption that sequences exist independently of their amplitudes, but you haven’t justified why the observer should expect a uniform distribution rather than one weighted by the wavefunction’s structure. This is precisely the question that needs to be answered, not assumed away. Quentin > -- > 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 visit > https://groups.google.com/d/msgid/everything-list/CAFxXSLQs-CC2_ptu3c%3DkMtbtL2REV%3Dx9kGWug55wB%3D%3DhxZ_RNw%40mail.gmail.com > <https://groups.google.com/d/msgid/everything-list/CAFxXSLQs-CC2_ptu3c%3DkMtbtL2REV%3Dx9kGWug55wB%3D%3DhxZ_RNw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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