On Sat, Apr 9, 2022 at 12:25 PM smitra <smi...@zonnet.nl> wrote: > On 09-04-2022 01:07, Bruce Kellett wrote: > > > > The trouble here is that his argument about Bell's theorem uses his > > own peculiar derivation. Derivations invoking counterfactual reasoning > > abound, but Bell did not prove his theorem in this way. If the theorem > > can be proved without using counterfactual reasoning, then > > counterfactual reasoning is not essential to the proof. > > > > Tim Maudlin has an interesting take on this; see arxiv:1408.1826. > > Maudlin points out that Bell did not assume either Determinism or > > counterfactual definiteness in his proof. He derived determinism by > > pointing out that if the theory is EPR local, then the reactions of > > the measuring devices must be predetermined by some element of reality > > in the system. This is a derivation of determinism for a local theory, > > which simultaneously derives the condition sometimes called > > 'counterfactual definiteness'. But Bell does not assume an EPR local > > theory -- he shows that such a theory contradicts quantum mechanics.. > > Counterfactual reasoning, or counterfactual definiteness, have no > > place in his argument. > > > > https://en.wikipedia.org/wiki/Bell%27s_theorem > > "Its derivation here depends upon two assumptions: first, that the > underlying physical properties PQ, PR, PS, PT exist independently of > being observed or measured (sometimes called the assumption of realism); > and second, that Alice's choice of action cannot influence Bob's result > or vice versa (often called the assumption of locality)" > > This allows for the counterfactual reasoning Bell uses in the > derivation. >
Wikipedia is not always a reliable source. > > > https://en.wikipedia.org/wiki/Bell%27s_theorem#Many-worlds_interpretation_of_quantum_mechanics > > "The Many-Worlds interpretation, also known as the Everett > interpretation, is local and deterministic, as it consists of the > unitary part of quantum mechanics without collapse. It can generate > correlations that violate a Bell inequality because it doesn't satisfy > the implicit assumption that Bell made that measurements have a single > outcome. In fact, Bell's theorem can be proven in the Many-Worlds > framework from the assumption that a measurement has a single outcome. > Therefore a violation of a Bell inequality can be interpreted as a > demonstration that measurements have multiple outcomes." > What a remarkably silly argument. The writer here is claiming that since Bell's theorem doesn't apply to many worlds, many worlds can give a local account of the correlations. It is amazing that so many people claim this, but no one has ever given this remarkable local account of the Bell correlations; in many worlds, or in any other theory. 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLTFqJPB6kZOS3_%3DB%3DUyQ%2BRFhpJ4q0wXfwJXBpT7EB0U0w%40mail.gmail.com.
