Abstract

This dissertation focuses on the one feature most clearly shared by the otherwise very different metaphysical systems of Aristotle, Descartes and Leibniz---i.e., the role of each in providing foundations for a system of natural science. Chapters 1 and 2 are devoted to a discussion of how Aristotle's metaphysics is foundational for his natural science. Chapters 3 and 4 do the same for Descartes and Leibniz. ;The thesis of the first two chapters is that for Aristotle, since scientific understanding of an object requires an understanding of its causes, and the unmoved movers are causes of every other substance, metaphysics is foundational for natural science because an understanding of the genus dealt with only by metaphysics is required for a proper understanding of the genus dealt with by the physicist . ;The thesis of the third chapter is that in the Meditations Descartes was never concerned to argue that bodies consist in nothing but their extension and certain essential modifications of extension; rather, Descartes was concerned: to establish that the ontology presupposed by his physics is one to which the human intellect is naturally bound by its limited stock of innate ideas; and to argue that this ontology is true even though possibly inadequate---i.e., that it is true at least insofar as it goes. ;In the final chapter I offer support for a commonly held, though not universally endorsed, interpretation of Leibniz's metaphysics. On this interpretation, Leibniz holds that the entities which make up the natural world are one and all phenomenal---i.e., confused representations of an underlying reality which consists in nothing but monads and their states. In support of this interpretation I try to show how to reconcile Leibniz's ostensibly conflicting pronouncements regarding the nature of body, and in doing so I offer a new explanation of the relation that obtains, according to him, between monads and the phenomena that make up the natural world