ABSTRACT
This chapter considers Spinoza’s development of the Cartesian system. The uniqueness of substance was Spinoza’s answer to the main problem in the philosophy of Descartes, a near contemporary Spinoza, who held that the attributes of extension and thought define numerically distinct substances, with the result that they are causally related. Spinoza developed the same system in many respects, in as much as according to the absolute idealist reading the system of finite and infinite perspectives in substance is like the system of monads. But Leibniz’s objection to Spinoza’s main proof of the uniqueness of substance in the Ethics suggests that the difference in the ways the whole of reality appears as conceived through diverse attributes entails a numerical diversity of substances. The development of Descartes’ system in the direction of Spinoza’s monism contains a significant advantage. Spinoza also regarded the modes of substance as modifications of something remaining stable throughout.
