Aristotelian Powers

Aristotle's theory of causation has multiple threads, and his texts invite multiple interpretations. The variation in interpretation is, in part, a result of different perspectives and questions that are brought to the text. For instance, Aristotle's theory of the four causes has invited scrutiny from contemporary philosophers of science, who are interested in theories of explanation (van Fraassen 1977) as well as philosophers of biology, who are interested in teleology, taxonomy and other concepts. (Gotthelf 1987) This paper looks at Aristotle's theory of causal powers in relation to contemporary realist theories of causation in science and social science. Rather than try to dress Aristotle in contemporary philosophical fashion, however, I will simply describe his views on the relationship between causal powers in general, and causal powers that operate with reason. I will also describe the metaphysics presupposed by his realist theory of causal powers. The first topic should interest philosophers trying to extend a realist account of causation from the physical sciences to the social sciences. The second topic is of relevance to contemporary philosophers interested in exploring the metaphysical commitments of causal powers. I devote particular attention to the ontology of causal powers as Aristotle develops it in Metaphysics IX. (Witt 2004) 1 This focus will allow me to develop two points. First, Aristotle's realist ontology of causal powers faces a challenge, which leads him to distinguish two ways of being for causal powers. Aristotle finds it necessary to defend the existence of inactive causal powers because of the challenge of Megarian actualism. The Megarians hold that a causal power only exists while and so long as it is active. A person can build a house only when she is actually building it; a fire can heat water only when it is actually heating water; an object is perceptible only when it is actually being