The varieties of agential powers

The domain of agential powers is marked by a contrast that does not arise in the case of dispositions of inanimate objects: the contrast between propensities or tendencies on the one hand, and capacities or abilities on the other. According to Ryle (1949), this contrast plays an important role in the ‘logical geography’ of the dispositional concepts used in the explanation and assessment of action. However, most subsequent philosophers use the terms of art ‘power’ or ‘disposition’ indiscriminately in formulating central metaphysical claims about human agency, assuming that an adequate account of inanimate dispositions can safely be used for such purposes. As a result, the distinctive features of propensities and capacities drop out of view. This is bound to obscure distinctions of crucial importance to the understanding of human agency. In order to show this, I undertake to articulate some central differences between propensities and capacities. Propensities and capacities have a different relation to value, as well as a concomitant difference in their metaphysical structure. The argument points to an explanation of why the distinction between propensities and capacities does not arise in the case of non-agential powers. This explanation takes us back to questions about the nature of human agency.