On Tue, Nov 19, 2024 at 5:11 AM PGC <[email protected]> wrote:
> On Monday, November 18, 2024 at 7:03:02 AM UTC+1 Bruce Kellett wrote: > > On Mon, Nov 18, 2024 at 4:17 PM PGC <[email protected]> wrote: > > Bruce, let’s directly address the epistemic interpretation of the > wavefunction. While this view neatly avoids ontological commitments and > sidesteps issues like FTL action, it doesn’t fully account for > experimentally observed phenomena such as violations of Bell’s inequalities. > > The violation of Bell inequalities implies non-locality, and the epistemic > interpretation of the wave function is perfectly compatible with > non-locality. > > These correlations are not just statistical artifacts of knowledge > updates; they point to an underlying structure that resists dismissal as > mere epistemic bookkeeping. The wavefunction’s role in consistently > modeling entanglement and its statistical implications suggests questioning > the existence of a deeper reality, challenging the sufficiency of an > epistemic-only framework. > > > Unfortunately, Everettian QM, or MWI, cannot even account for the > correlations, much less the violations of the Bell inequalities. I have > made this argument before, but failed to make any impact. Let me try again. > > The essence of Everett, as I see it, is that every possible outcome is > realized on every experiment, albeit on separate branches, or in disjoint > worlds. Given this interpretation, when Alice and Bob each separately > measure their particles, say spin one-half particles, they split at random > on to two branches, one getting spin-up and the other branch seeing > spin-down. This happens for both Alice and Bob, independent of their > particular polarization orientations. If this were not so, the correlations > could be used to send messages at spacelike separations, i.e, FTL. > > If N entangled pairs are exchanged, each of Alice and Bob split into 2^N > branches, covering all possible combinations of UP and DOWN. When Alice and > Bob meet, there is no control over which Alice-branch meets which > Bob-branch. If the branch meet-up is random, then in general there will be > zero correlation, since out of the 2^N Bob branches for each Alice branch, > only one will give the observed correlations -- a 1/2^N chance. In the > literature, some attempts have been made to solve this problem: for > instance, it is sometimes claimed that Alice and Bob interact when they > meet, and this interaction sorts out the relevant branches. But no account > of any suitable interaction has ever been given, and also, one can reduce > the possible interaction between Alice and Bob to as little as desired, > say by having them exchange their data by email, or some such. Another > suggestion has been that since the original particles are entangled, some > magic keeps everything straight. I do not find either line of attempted > explanation in the least convincing, so I conclude that Everettian QM > cannot account for any correlations, much less those that are observed to > violate the Bell inequalities. > > Attempts to relate Everettian many worlds to computationalism, or theories > of everything, are just disingenuous. There is no reason why these > many-worlds theories should have anything in common. > > > Bruce, your assertion that the epistemic interpretation of the > wavefunction is compatible with non-locality and capable of addressing Bell > inequality violations deserves attention. While it is true that an > epistemic interpretation can align with non-local correlations, it > struggles to explain the coherence and structure underlying these > correlations. If the wavefunction is purely a representation of knowledge, > what enforces the observed statistical regularities that persist > independently of the observer? These correlations suggest a deeper reality > to the wavefunction itself, beyond an epistemic framework. > > You critique MWI on the basis of a "branch meet-up" problem, suggesting > that the coherence of correlations collapses due to arbitrary branch > matching. However, this interpretation mischaracterizes the role of the > wavefunction in Everettian QM. The wavefunction evolves unitarily, > preserving coherence across all branches. Correlations between Alice and > Bob emerge from the shared history of their entangled particles, embedded > in the global structure of the wavefunction. The branches are not randomly > assigned but are intrinsically connected through their common origin in the > unitary evolution. This global coherence ensures the persistence of > correlations without requiring post-measurement sorting. > That is not an explanation of how the correlations arise. You are just relying on magic, without giving any coherent account of the process. 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/CAFxXSLT-QEpJqPEYjdPtu3ZzFQLvwYPLMyCn96%2B41AWz6KQVDA%40mail.gmail.com.
