Spinoza's simplest bodies

In the entirety of his corpus, Spinoza uses the phrase ‘simplest bodies’ [corporibus simplicissimis] exactly twice and never offers an explanation of what it means. That said, it appears to play a fundamental role in his thought. This paper evaluates two twentieth-century readings of Spinoza in order to present a new original theory of simplest bodies. Ultimately, I present a reading of Spinoza which accepts a nuanced amalgamation of these accounts. I argue that the right understanding of Spinozistic simplest bodies is something like the following: simplest bodies are portions of extension featuring motive homogeneity among their necessarily infinite parts. For Spinoza, simplest bodies thus feature no mereological simplicity at all, but rather only motive simplicity, in that they are properly characterized by a single ratio of motion and rest.