Of Light and Double-Slit Experiments

The physics Thunderdome: Two theories enter… and two theories leave, with neither of them being a clear winner.

Yes, everybody agrees to that—but the controversy is about what, exactly, those assumptions are, with one camp claiming it’s a combination of ‘locality’ and a further assumption, often phrased as ‘realism’, ‘counterfactual definiteness’, ‘hidden variables’ or the like, while the other maintains that ‘locality’ alone suffices.

The received view is the former—to prove Bell’s theorem, you need both locality and some assumption that boils down to incompatible observables simultaneously having definite, albeit not simultaneously observable, values. Becker’s book, and also George Musser’s recent work Spooky Action at a Distance, pretty much take the line that the latter camp is correct, which is at least premature (and by my lights, pretty much dead wrong).