For more than a century after its appearance on the modern philosophical scene, Spinoza’s philosophy was considered surprising and even scandalous for its assertion of the oneness or singularity of substance. From Bayle’s early Dictionary article to Hegel’s Lectures on the History of Philosophy, the core of Spinoza’s philosophy was said to be its unprecedented gesture of making God the sole res that could be thought through the concept of substance. Substance, according to definition 3 of part I of the (...) Ethics, is “that which is in itself and is conceived through itself.” The enormous emphasis placed on this move by the interpretative tradition almost into the twentieth century managed, however, to obscure every other dimension of Spinoza’s thought, so that Spinoza’s thought was simply a metaphysics of the oneness of substance. It is this coupling of Spinozism and the metaphysics of substance that I want to undo. In line with a series of interpretative developments in France over the last thirty years, I want to dispel this identification by employing a paradoxical formulation. Far from being a metaphysics of substance, I contend that Spinoza’s philosophy is instead an ontology of relation. By emphasizing his negation of the substantiality of what he calls res singulares, we can locate Spinoza’s originality less in having posited the existence of a single substance—Letter 50 in fact suggests that substance can only “improperly” be called “single” or “one”—than in having laid out the foundation for this ontology of relation. (shrink)