On Wed, Apr 6, 2022 at 10:14 AM smitra <smi...@zonnet.nl> wrote: > On 06-04-2022 01:14, Bruce Kellett wrote: > > On Wed, Apr 6, 2022 at 9:03 AM smitra <smi...@zonnet.nl> wrote: > >> On 06-04-2022 00:21, Bruce Kellett wrote: > >>> On Wed, Apr 6, 2022 at 1:13 AM smitra <smi...@zonnet.nl> wrote: > >>>> > >>>> The conclusion that local hidden variables are rules out does depend > on > >>>> an argument about what would have happened had different polarizer > >>>> setting been used than the ones that were actually used. > >>> > >>> That is false. Where in the Aspect experiments is reference made to > >>> non-performed measurements? > >>> > >> > >> It's in the argument that local hidden variable theories must satisfy > >> Bell's inequalities. > > > > You are stretching things quite a bit. All Aspect needed to do was > > show that his measured results violated the inequalities. No > > counterfactual reasoning involved. If you then want to argue that > > Aspect's results extend to all possible such experiments, then of > > course, not all those experiments have been done. But that does not > > impact Bell's theorem. Bell, himself, did not have to make any > > measurements. > > How does one conclude that a set of measurement results cannot be > explained by a local hidden variable theory if you don't invoke > counterfactual reasoning to the performed experiment?
That is a rather trivial appeal to counterfactual reasoning. Such an appeal is not unique to Bell's theorem -- it applies to any theory that is confronted with experiment. A theory will state that "if you measure such-and-such, or perform such-and-such an operation, the following will happen (or not happen)." That is the only type of counterfactual involved in applying Bell's theorem to Aspect's results to rule out a local HV account. Bell's theorem itself is independent of any such counterfactual reasoning. He simply derives an inequality that any local theory must satisfy. This may be cast in the form of counterfactuals, if desired. But that is true of any theory. Bell does not depend on counterfactual reasoning. To go further with analysis of Rubin's argument, he states: "Each particle, even before its spin is measured by the analyzer, carries with it information—“instruction sets,”—determining what its response will be to the analyzer in every possible orientation." This is a fatal assumption. It is ruled out by the Kochen-Specker theorem which proves that no such complete set of instructions is possible. This is where Rubib introduces counterfactuals -- if a complete set of instructions for every angle is possible, then one can (counterfactually) ask what would happen if the polarizers are at auch-and-such an angle. But none of this is possible. And counterfactuals do not arise. In any case, Bell did not argue in this way. > Of course, Aspect could simply refer to Bell's theorem, but Bell's theorem > relies heavily > on counterfactual reasoning. No, it does not. The claims by Rubin: "Bell's theorem depends crucially on counterfactual reasoning....."; and "Bell's theorem is avoided because the counterfactual reasoning which leads to it is not required, and cannot be justified." are just assertions. No textual evidence is provided that Bell ever used counterfactual reasoning in any way. His proof is independent of counterfactuals. Rubin gives a derivation of Bell inequalities that does refer to non-performed experiments. But that appeal is not necessary (and invalid); Bell himself did not reason in this way. This is also why you can have > superderminisitic loopholes to the argument against local deterministic > theories. The superdeterministic argument stems from Bell's assumption of statistical independence: the claim that the distribution of the hidden variables does not depend on the future settings of either polarizer. It is part of Bell's understanding of locality and separability. He explicitly rules out superdeterminism as absurd. Again, nothing to do with counterfactuals. 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/CAFxXSLRoPA0q-WQxy1Ks_c9U6aK3e9pVk%3D9rqPEv4rE33V%3Doyg%40mail.gmail.com.
