What Are Manifestations?

There is widespread agreement among friends of irreducible powers that powers are properties, and intrinsic ones at that. But when it comes to what is produced by the exercise of powers, little has been said about what sort of ontological category these ‘manifestations’ belong to, and even less agreement is to be found. The default response seems to be that manifestations are events, but a few recent proposals treat manifestations as properties or processes. Though these proposals boast a number of virtues, I argue that any view that understands manifestations these ways has unsavoury consequences that outweigh any virtues on offer. Those unsavoury consequences come to light when we consider manifestations that go awry. In particular, I consider an attempted poisoning foiled by antidote, wherein the circumstances required for the power’s triggering have been satisfied, but the anticipated causal chain is frustrated. One the one hand, it seems mistaken to say that the power has been manifested, as the characteristic manifestation—death—has been avoided. But on the other hand, it seems equally wrong to claim that the power was not manifested, given that the conditions required for the display of the power were met and the expected causal process began, despite not running to completion. I thus propose that we think of manifestations as being extremely short-lived, ideally as states of affairs. En route to that conclusion some important discoveries about powers-based causation are made apparent.