Le ven. 14 févr. 2025, 16:23, Alan Grayson <[email protected]> a écrit :
> > > On Friday, February 14, 2025 at 2:41:44 AM UTC-7 Quentin Anciaux wrote: > > > > Le ven. 14 févr. 2025, 10:29, Alan Grayson <[email protected]> a écrit : > > > > On Friday, February 14, 2025 at 2:17:37 AM UTC-7 Quentin Anciaux wrote: > > > > Le ven. 14 févr. 2025, 10:08, Alan Grayson <[email protected]> a écrit : > > > On Friday, February 14, 2025 at 1:37:20 AM UTC-7 Quentin Anciaux wrote: > > Le ven. 14 févr. 2025, 06:13, Brent Meeker <[email protected]> a écrit : > > > > On 2/13/2025 4:57 AM, John Clark wrote: > > On Wed, Feb 12, 2025 at 5:41 PM Brent Meeker <[email protected]> wrote: > > *>> Schrodinger's Equation is 100% deterministic, so why is it necessary > to resort to probability at all?* > > > > > *Because one thing of many possible happens.* > > > > *Why is that "one" thing special? I can answer that; because it's not > special, many things happen, everything that is not forbidden happens. You > have no answer to that question other than "because it is". * > > The only thing special about is that it's the one that happened. If > everything not forbidden happens then you're going to need to explain what > probabilty means. > > > * > I can write an equation for the toss of die that shows that the > probability of each face is 1/6. That equation is deterministic. It > determines probabilities. And probabilities tell you that some things > happen and some don't. Not that every face of the die comes up on every > throw.* > > > > *Schrodinger's equation produces a complex-valued wave that evolves in > time, the square of the absolute value of the amplitude of that wave > determines probabilities. You just take the Born Rule as a given because > experimenters tell you that it works. Many Worlds can tell you why it works > and why you need it. * > > So you say. But all attempts to derive it, assuming MWI, have failed. I > look forward to your paper. > > > *And unlike Schrodinger's Equation your dice equation directly determines > a probability* > > Not as directly as Schrodinger's equation determines QM proability > amplitudes. > > *; classical physics doesn't have or need a counterpart to the Born Rule > (although the square of the absolute value of an electromagnetic wave is > proportional to its energy). Classical physics can provide us with an > excellent approximation of how the orientation of the die will change in > time, so why do we need to use probability? The reason for that is > practical not fundamental, sometimes in classical physics tiny changes in > initial conditions lead to exponentially diverging trajectories over time, > and you're never going to know the initial conditions exactly, and even if > you did you don't have the computing capacity to use them.* > > *> And you have no answer to what probability means, until you resort to > "uncertainty of self-location",* > > > *Resort to? If I'm not allowed to give the correct answer then my answer > is going to be wrong. Many Worlds says everything always obeys > Schrodinger's equation including the observer, therefore there will always > be self-location uncertainty, it can't be avoided. * > > And how does that result in uncertainty, when you are located in every > branch. It's just the problem of what does probability mean when > everything happens. You're just pushing the problem around. > > Brent, > > The problem isn’t that "everything happens"—it’s *how often* different > things happen from the perspective of an observer. Probability in MWI > doesn’t mean "some branches exist and others don’t" but rather that an > observer finds themselves in certain branches *proportionally* to their > measure. > > Saying "you’re just pushing the problem around" ignores that probability > in any framework is about *expectations for future experience* based on > structure. In a single-world view, you justify probabilities by appeal to > hypothetical ensembles or repeated trials that never actually happen. In > MWI, the structure of the wavefunction provides the ensemble *within* > reality, and measure determines where most instances of an observer exist. > > Also, I’m not specifically advocating for MWI. I lean more towards *a > computational theory of reality*, where measure and probability emerge > from an underlying informational structure. But I do favor frameworks where > *everything > happens* rather than a single unique history set in stone forever. > > *Then you'll like this: * > *In a horse race, according to the MWI, multiple worlds come into > existence for all possible winners in a particular race. But for one given > race, are there are not multiple worlds, possibly countably infinite, which > come into existence for every possible way in which the winner wins, while > retaining the finishing order of the losing horses? I think so, and is the > reason I find the MWI and its devotees, lacking in discrimination. But for > a discerning eye, it's in the eye of the beholder, of Schrodinger's > equation. AG * > > > AG, > > That’s exactly the point, MWI doesn’t just split for the winner, it splits > for every possible microscopic detail of the race, including variations in > how each horse crosses the finish line, fluctuations in the crowd, air > molecules, and so on. The number of branches isn’t just countably infinite; > it follows the continuous evolution of the wavefunction. > > But calling that "lacking in discrimination" misses the core idea. It’s > not about choosing which worlds are "important", it’s about unitary > evolution preserving all possible outcomes. The structure is dictated by > Schrödinger’s equation, not by human intuition about what "should" count as > a distinct event. > > If you think that level of detail makes MWI unreasonable, you should also > reject classical probability, where every possible dice roll, coin flip, or > weather pattern is part of a notional ensemble. The only difference is that > MWI doesn’t assume unrealized outcomes "disappear" without explanation. > > Quentin > > > *So every wiggle of your finger or toe results in perhaps uncountable > worlds coming into existence, as well as every random turn of a flying > insect? It just doesn't pass the smell test. AG * > > > AG, > > Yes, every quantum interaction leads to branching—whether it’s a photon > reflecting off your skin or an insect flapping its wings. But the mistake > is thinking of this as “new worlds popping into existence.” MWI doesn’t add > anything extra, it simply follows unitary evolution, where all possible > outcomes exist in superposition. > > What doesn’t pass the smell test is the idea that only one history is > mysteriously “chosen” while the rest, dictated by the same Schrödinger > equation, vanish without explanation. > > > What's the difference between an outcome not realized, and a branch which > is disjoint from this world (and BTW, what is a branch)? AG > AG, An unrealized outcome in a single-world interpretation means it never happened, it was just a hypothetical, a calculation tool that never manifested in reality. In MWI, an alternative outcome is not "unrealized" but real in a disjoint branch, it exists, but in a different part of the wavefunction that no longer interferes with ours. A branch is simply a part of the universal wavefunction that has decohered from others due to interactions with the environment. Once decoherence happens, branches stop interfering, effectively behaving as separate classical-like worlds. So the key difference is: in single-world views, unrealized outcomes are fiction, never happened, never will, never experienced, never interacted; in MWI, they are real but inaccessible due to decoherence. Quentin > > If you accept quantum mechanics, you already accept that reality operates > in a way that defies classical intuition. Rejecting MWI because it feels > excessive is just favoring one form of weirdness over another. > > Quentin > > > > Saying 'some things happen and others don’t, just because' is not an > explanation—it’s an arbitrary assertion, no better than saying 'God did it > that way.' A real theory should provide a mechanism for why certain things > are observed rather than simply declaring them to be the case. > 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/481e369b-3123-4a86-814d-e1c4edf869a9n%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/481e369b-3123-4a86-814d-e1c4edf869a9n%40googlegroups.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 visit > https://groups.google.com/d/msgid/everything-list/d7b79b51-84da-4144-a04f-a0abbc05b250n%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/d7b79b51-84da-4144-a04f-a0abbc05b250n%40googlegroups.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 visit > https://groups.google.com/d/msgid/everything-list/a2708f1c-c023-43ca-876a-e0eb3e4218b1n%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/a2708f1c-c023-43ca-876a-e0eb3e4218b1n%40googlegroups.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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