Abstract: In addition to the notion of causal law, the concept of capacity, modelled on Mill's notion of tendency, is required to make sense of standard methods in econometrics and standard accounts of probabilistic causality. General causal claims are shown to be ascriptions of capacities while causal laws are local causal claims, relative to a test population. Capacities are at a higher level of modality and are not reducible to causal laws, as causal laws are not reducible to laws of association that describe mere regularities; but unlike laws of association, capacities are real.

Keywords: capacity, causal laws, econometrics, Mill, probabilistic causality, regularities,