Philosophy, Department of


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Published (as Chapter 5) in The Metaphysics of Powers: Their Grounding and their Manifestations, ed. Anna Marmodoro (New York: Routledge, 2010), pp. 73–83.


Copyright © 2010 Taylor & Francis. Used by permission.


According to a standard characterization of dispositions, when a disposition is activated by a stimulus, a manifestation of that disposition typically occurs. For example, when flammable gasoline encounters a spark in an oxygen-rich environment, the manifestation of flammability—combustion—occurs. In the dispositions/powers literature, it is common to assume that a manifestation is an effect of a disposition being activated. (I use “disposition” and “power” interchangeably). I address two questions in this chapter: Could all manifestations be effects that involve things acquiring only dispositional properties? And, is thinking of manifestations as contributions to effects preferable to thinking of them as effects? I defend negative responses to both questions.

If all properties are dispositional, as the pandispositionalists claim, then any time the activation of a disposition results is something acquiring a new property, it results in something acquiring another disposition. Some worry that a vicious regress ensues (Swinburne, 1980; Bird, 2007a, 2007b: 132-46). While I believe that regress arguments can be addressed, my worry is that, on the pandispositionalist view, manifestations become unobservable.

Thinking of manifestations as effects is problematic in cases where what actually occurs is not the kind of effect that the power is a power for, but rather a complex interaction of various powers. Because of this, some prefer to think of manifestations as contributions to effects (Molnar, 2003: 194-8; Mumford, 2009). I argue against this proposal on the ground that it introduces mysterious new entities into our ontology. In the end, the most plausible view is that a single kind of power can have different kinds of effects, some of which involve the instantiation of non-dispositional properties.

I proceed as follows. In the first section of this chapter, I show that the philosophical concept of a manifestation is the concept of an effect. In the second section, I argue against the claim that all manifestations involve instantiations of only dispositional properties. In the third section, I argue against the view that manifestations are contributions rather than effects.

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