Counterfactual Reasoning in the Bell-EPR Paradox

Abstract

Skyrms's formulation of the argument against stochastic hidden variables in quantum mechanics using conditionals with chance consequences suffers from an ambiguity in its “conservation“ assumption. The strong version, which Skyrms needs, packs in a “no-rapport” assumption in addition to the weaker statement of the “experimental facts.“ On the positive side, I argue that Skyrms's proof has two unnoted virtues (not shared by previous proofs): (1) it shows that certain difficulties that arise for deterministic hidden variable theories that exploit a non-classical probability theory extend to the stochastic case; (2) the use of counterfactual conditionals relates the Bell puzzle to Dummett's (1976) discussion of realism in quantum mechanics.