Brent, You say the Born rule is justified empirically, which is true. But empirical justification is not the same as theoretical derivation. If we only appeal to empirical evidence, then we are just restating that the rule works, not explaining why it follows from unitary evolution.
The problem isn’t whether the Born rule is correct—it clearly is—but whether its connection to amplitude can be derived within MWI rather than imposed. Saying "probabilities are just what happens" is not an explanation, it’s an assertion. You keep insisting that decoherence doesn’t justify why amplitudes should determine observer frequency. But if amplitudes dictate the behavior of quantum systems in all other cases, why would they suddenly stop mattering when it comes to what observers experience? You haven’t answered that—you’ve just stated that amplitudes don’t determine frequency without justification. As for the "bush of worlds," decoherence doesn’t create separate worlds—it describes why interference becomes negligible, leading to effectively independent branches. The number of observer instances per branch is what’s at stake. If amplitude plays no role in observer distribution, then why does the Born rule hold? If you believe MWI cannot account for the Born rule, then you need a reason why amplitudes should stop affecting probabilities at the moment of measurement, despite governing quantum evolution everywhere else. Otherwise, you’re just stating the rule rather than explaining it. Quentin Le sam. 22 févr. 2025, 02:26, Brent Meeker <[email protected]> a écrit : > > > On 2/21/2025 1:41 PM, Quentin Anciaux wrote: > > Brent, > > The Born rule is not something that "should" be obeyed—it is obeyed in > experiments. The question is why. Saying "some things happen and others > don’t" doesn’t answer that. > > That's my answer to what probabilities mean. And the Born rule says the > squared amplitudes of Schroedinger's equation should be interpreted as > probabilities. > > If amplitudes determine the behavior of quantum systems in every other > context, why would they suddenly become meaningless when it comes to > observer experiences? That’s what you need to justify. > > It's justified empirically. You're the one claiming in follows from the > Schroedinger equation. Justify that. > > > You claim that talking about observers is "obfuscation," but probability > itself is about expectations—what an observer should expect to see given > the structure of the theory. If multiple observers look at the same SG > detector, yes, they all see UP. But why was that outcome observed with > probability a² rather than any other distribution? > > Because the Born rule. But according you it's because somehow decoherence > produces a bush or identical worlds for each outcome. > > Ignoring that question doesn’t make it go away. > > Ignoring that having ten people in room looking at the result doesn't > increase it's probability doesn't help. So where is your explanation of > how the bush of worlds gets produced? > > > The challenge for any interpretation—whether MWI, collapse, or anything > else—is to explain why experiments follow the Born rule. Dismissing the > problem as circular without engaging with why amplitudes might determine > observer frequencies is avoiding the issue, not resolving it. > > We've know for over a century that the amplitudes determine the > frequencies, that was Born's insight. But that's just stating the Born > rule. Science can only answer "Why?" questions in terms of deeper theory. > So far none has been forthcoming. > > Brent > > -- > 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/72f3aafe-7d82-4916-9667-18cb20342806%40gmail.com > <https://groups.google.com/d/msgid/everything-list/72f3aafe-7d82-4916-9667-18cb20342806%40gmail.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/CAMW2kAqW3gsBJmCk2NOCD2YPM9p4rga%2BYAWi7JkZu4j-OeHXFQ%40mail.gmail.com.
