Abstract

This dissertation explores how causal powers connect in Aristotle's system to Aristotelian causation, hylomorphism and the composition and nature of material objects, and possibility and necessity. I argue that active causal powers are efficient causes, explain what their causal activity consists in, and show how this is consistent with Aristotle's alternating identification of powers with form and with matter. I argue that the ``way of being'' that corresponds to powers, ``being in potentiality,'' should not be understood as being possible or as a restriction of being possible; and I offer an alternative non-modal interpretation of the way of being. Nonetheless, I argue, Aristotle thinks of powers as the foundation and explanation of modality. This naturally gives rise to a conception of possibility where possibility is tied intimately to time. I finish by explaining how this conception of modality relates to some of Aristotle's notorious commitments with respect to that tie, especially his claim that every possibility is eventually realized and what is always true must be true.