According to ecological psychology, animals perceive not just the qualities of things in their environment, but their affordances: in James Gibson’s words, ’what things furnish, for good or ill’. I propose a metaphysics for affordances that fits into a contemporary anti-Humean metaphysics of powers or potentialities. The goal is to connect two debates, one in the philosophy of perception and one in metaphysics, that stand to gain much from each other.

The basic kinds of physical causality that are foundational for other kinds of causality involve objects and the causal relations between them. These interactions do not involve events. If events were ontologically significant entities for causality in general, then they would play a role in simple mechanical interactions. But arguments about simple collisions looked at from different frames of reference show that events cannot play a role in simple mechanical interactions, and neither can the entirely hypothetical causal relations between events. (...) These arguments show that physics, which should be authoritative when it comes to the metaphysics of causality, gives no reasons to believe that events are causal agents. Force relations and some cases of energy-momentum transfer are examples of causal relations, with forces being paradigmatic in the macroscopic world, though it is conceivable that there are other kinds of causal relation. A relation between two objects is a causal relation if and only if when it is instantiated by the two objects there is a possibility that the objects that are the terms of the relation could change. The basic metaphysics of causality is about objects, causal relations, changes in objects, and a causal primitive. The paper also includes a discussion of the metaphysics of forces and a discussion of the metaphysics of energy and momentum exchanges. (shrink)

It is held by some philosophers that it is possible that x has a disposition D but, if the stimulus condition obtains, it won’t manifest D because of an intrinsic interference. I will criticize this position on the ground that it has a deeply sceptical consequence, for instance, that, assuming that I am not well informed of the micro-properties of a metal coin, I do not know that it is not water-soluble. But I urge that this is beyond the pale, (...) especially in light of the weight of the practical considerations we take when we use dispositional concepts in everyday life or science. In doing so, further, I will formulate a type of belief-forming inference and claim that it confers justification on commonsensical dispositional beliefs like the one that a metal coin isn’t water-soluble. (shrink)