Philosophy, Department of


Date of this Version



Published (as chapter 6) in Metaphysics and Science, ed. Stephen Mumford and Matthew Tugby (Oxford: Oxford Univ. Pr., 2013), pp. 123-137.


Copyright © 2013 Oxford University Press. Used by permission.


According to most views of dispositions or powers, they have “triggers” or activation conditions. Fragile things break when they are struck; explosive things explode when ignited. The notion of an activation event, or “trigger,” is central to the notion of a disposition. Dispositions are defined not only by their manifestations, but also by their triggers. Not everyone who grumbles and complains counts as irritable—just those who do so with little inducement. Not everything that can be broken counts as fragile—just things that can be broken with relatively little force. The idea that triggers are part of the identity conditions of powers is evident in conditional analyses of powers, and even in the claim that certain conditionals are typically true of things with certain powers. The antecedent of the conditional corresponds to a trigger of that power: “If it’s struck, it will break” is true of a fragile thing, and “being struck” is the trigger.

In this chapter, I explore the nature of activation events and their relation to the powers they activate. In particular, I will consider what triggers would look like if all properties were powers, as the dispositional monist or pandispositionalist tells us they are. While many have expressed worries about manifestations involving instantiations of only dispositional properties, it is also worth noting that, on a pandispositionalist scenario, the activation event must be equally dispositional. If all properties are powers, it seems that a triggering event must be an acquisition of a power. But how does something acquiring a power activate another power to produce its manifestation? I suggest and evaluate possible answers. I will argue that, as with the case of manifestations, a vicious regress threatens the pandispositionalist picture of power activation. I go on to consider several possible pandispositionalist responses.