The metaphysics of substance and the metaphysics of thought in Spinoza (Benedictus de Spinoza)

In the first two chapters of the dissertation I propose a new interpretation of the metaphysics of substance in Spinoza. Against Curley's influential interpretation of the substance-modes relation, I argue that for Spinoza, modes both inhere in, and are predicated of, God. Relying on extensive textual evidence I show that Spinoza considered modes to be God's propria. Against the claim that it is a category-mistake to consider things as properties, I argue that the distinction between things and properties has been thoroughly undermined both in the early modern period (primarily, in the works of Descartes, Arnauld & Nicole, Leibniz, and Hume) and in contemporary metaphysics (in bundle theories, and some versions of trope theory). Following this elucidation of the substance-mode relation, I explain Spinoza's concept of "immanent cause" (an efficient cause, whose effect inheres in it), and explain why the interpretation of Spinoza's modes as merely illusory beings (an interpretation which was propagated by the German Idealists) is wrong.; In the last to chapters of the dissertation, I put forward two interrelated theses about the structure of the attribute of thought and its overarching role in Spinoza's metaphysics. First, I show that our current understanding of Spinoza's pivotal doctrine of parallelism is inaccurate. I argue that Spinoza had not one, but two independent doctrines of parallelism. The Ideas-Things Parallelism stipulates an isomorphism between the order of ideas in the attribute of thought and the order of things in nature. The Inter-Attributes Parallelism establishes an isomorphism among the order of modes in each of the infinitely many attributes. I show that these two doctrines are independent of each other and that each has different implications.; Relying on my clarification of the doctrines of parallelism, I develop my second main thesis. Here I argue that, for Spinoza, ideas have multifaceted (in fact, infinitely-faceted) structure that allows one and the same idea to represent the infinitely many modes which are parallel to it in the infinitely many attributes; each idea has infinitely many aspects and each aspect represents the same mode of God under a different attribute. To that extent, Thought turns out to be coextensive with the whole of nature. Spinoza cannot embrace an idealist reduction of Extension to Thought because of his commitment to the conceptual separation of the attributes. Yet, within Spinoza's metaphysics, Thought has a clear primacy over the other attributes insofar as it is the only attribute which is as elaborate, complex and, in some sense, powerful as God (or as Spinoza puts it: "God's power of thinking is equal to his power of acting").