Summary: | This dissertation begins with the Islamic philosopher Avicenna, who transforms Aristotle’s conception of the efficient cause in the Metaphysics of his Shifā’. Its first goal is to examine the arguments which constitute Avicenna’s metaphysical account of agency. Its second goal is to examine Scholastic disputes about the causal powers of natural agents that arise in connection with his view. In its final chapter, it relates Medieval debates about efficient causality to Descartes’ account of the causal powers of bodies.
One of the original features of Avicenna’s account of agency is his argument for the claim that the existence of contingent things requires an efficient cause. This aspect of his view was influential in the Latin West. Avicenna also holds that the cause of the existence of contingent things is an incorporeal principle, which he describes as an agent who “bestows forms”. I argue that Avicenna fails to resolve the tension between this claim and his commitment to an Aristotelian account of generation. This failure sets the stage for Avicenna’s role in Scholastic disputes about the causal powers of natural agents in cases of generation.
Both Aquinas and Suarez attribute to Avicenna the view that generation requires the creation of form. They argue that generation occurs through natural processes. Suarez’s view includes the claim that the substantial form of a substance is an immediate efficient cause of its actions. Suarez defends this claim against other Aristotelians, who hold that a substantial form gives being to a composite substance as a formal cause and that the actions of substances depend directly on their accidents alone.
Descartes claims in his letter to Regius of January 1642 that it is absurd to hold that substantial forms are immediate principles of action. He thinks that bodies act in virtue of their modes. Here Descartes sides with those Aristotelians who hold that the actions of substances depend directly on their accidents alone. I argue that this aspect of Descartes’ view tells against Daniel Garber’s claim that his denial of substantial forms deprives bodies of causal efficacy.
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