Propensities and pragmatism

Abstract (for The Review of Metaphysics): This paper outlines a genuinely pragmatist conception of propensity, and defends it against common objections to the propensity interpretation of probability, prominently Humphreys’ paradox. The paper reviews the paradox and identifies one of its key assumptions, the identity thesis, according to which propensities are probabilities (under a suitable interpretation of Kolmogorov’s axioms). The identity thesis is also involved in empiricist propensity interpretations deriving from Popper’s influential original proposal, and makes such interpretations untenable. As an alternative, I urge a return to Charles Peirce’s original insights on probabilistic dispositions, and offer a reconstructed version of his pragmatist conception, which rejects the identity thesis.