Abstract

There seems to be widespread agreement that there are two modal values: necessity and possibility. X is necessary if it is not possible that not-X; and Y is possible if it is not necessary that not-Y. In their path-breaking book, Rani Lill Anjum and Stephen Mumford defend the radical idea that there is a third modal value, weaker than necessity and stronger than possibility. This third value is dubbed 'dispositional modality' (DM) or 'tendency' and is taken to be an irreducible and sui generis worldly modality: "the modality that's everywhere" (5). The source of DM is the causal powers of particulars; hence, DM is constitutively involved in causation: "a cause tends or disposes towards its effect, and can sometimes succeed in producing it" (9). Accordingly, DM is involved in all causal processes, from fundamental physics to the social and moral realm. This "deeply tendential view" (11) of the metaphysics of nature is advanced as distinct from both extant neo-Aristotelian and Humean views. Its key feature is that there is neither pure contingency nor necessitation in nature.