Abstract

Deleuze (1990) reads Part I of the Ethics as articulating an expressionist philosophy, in which to express (exprimere) is the ontological criterion for existence throughout Spinoza’s metaphysical system. However, he argues that inadequate ideas and passions are non‑expressing, such that finite modes express substance only in their adequate ideas. I argue, contra Deleuze, that Spinoza’s account of the workings of the human mind presses us to understand inadequate ideas as genuine expressions of substance which nonetheless are specific to the individuals which form them. On the same textual grounds I propose that the mind’s expression of substance in inadequate ideas, and thus in virtue of its encounters with other modes, is a source of both creativity and potential instability. I put this insight to work in a reading of Spinoza’s political philosophy, arguing that expression generates a dynamic in which social formations enact and reinforce their own forms of expression, while also being subject to the reimaginations and expression of those who live within them.