Abstract

Leibniz sometimes tells us that there are only two fundamental types of mental states: perceptions and appetitions, that is, mental representations and desire-like states. While this may sound like an overly sparse ontology of mental states, the philosophy of mind that Leibniz builds from these elements is surprisingly nuanced and powerful. What makes this possible is that he distinguishes different sub-types of these mental states. Leibniz famously differentiates between unconscious and conscious perceptions, which gives him an advantage over philosophers like Descartes, for whom all perceptions are conscious. He also distinguishes between reflective and unreflective perceptions, as well as between degrees of perceptual distinctness. Leibniz furthermore follows scholastic thinkers like Thomas Aquinas in distinguishing different types of appetitions. Uncovering what those are and what roles they play in Leibniz’s philosophy of mind are the central aims of this chapter.