Let us call dispositional monism the view that all natural properties have their identities fixed purely by their dispositional features, that is, by the patterns of stimulus and response in which they participate. DM implies that natural properties are pure powers: things whose natures are fully identified by their roles in determining the potentialities of events to cause or be caused. As pure powers, properties are meant to lack quiddities in Black's sense. A property possesses a quiddity just in case (...) its identity is fixed by something independent of the causal–nomological roles it may enter into. Paradigmatically, a categorical property is thought of as a property whose identity is fixed by a quiddity .The key question about the viability of DM as a theory of properties is how properties can be pure powers devoid of any quiddity. Bird provides an answer. According to Bird , ‘all there is to a property is a matter of second-order relations to other properties’. The second-order relation is just the relation that a disposition, its stimulus condition, and a manifestation condition bear to each other. Call this relation SR. SR is not causation or physical necessitation. The latter relations are first-order relations between concrete events. SR is a second-order relation. Its possession by properties explains why events featuring those properties can enter into certain first-order relations of causation or necessitation.Bird's thought then is this: the sense in which properties have their identities fixed purely by their causal–nomological roles is that they are relationally constituted, where the relation doing the constituting is SR. 1 This thesis of relational constitution does not imply that natural properties are themselves relations. Nothing prevents the identity …. (shrink)