Capacities and Natures

Abstract

There are many arguments for denying capacities entitative status, but as they stand they are insufficient. On the one hand, there is the “stimulus-response” model for capacities.1 The logical form of a capacity proposition is, on this model, a modal conditional proposition; its antecedent expresses an operation in certain circumstances and its consequent expresses a realization of the putative capacity. Unless the conditional is explicitly modal, it cannot be relied upon to support a counterfactual conditional. But a capacity proposition does support some associated counterfactual conditional. The modality must be that of necessity.