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 -- 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.
