Early modern philosophers, such as Descartes and Spinoza, appeal to a theory of modes in their metaphysics. Recent commentators have argued that such a theory of modes has Francesco Suárez as its primary source. In this paper, I explore
one explicit source for Suárez’s view: Durand of St.-Pourçain, an early fourteenth-century philosopher. My aim will be mainly expository: I will put forward Durand’s theory of modes, thus correcting the persistent belief that there was no well-defined
theory of modes prior to Suárez. First, I will sketch out the historical and theological context in which Durand developed his theory, briefly canvassing some of the items that he treats as modes as well. Second, I will go over the distinctive features that
Durand thinks modes have. Finally, I will close with some reflection on why we should countenance modes in our ontology. Along the way, I will correct a few misconceptions about Durand’s theory of modes.