AAP 2026 CONFERENCE

Leibniz often uses a mirror analogy to explain his monads. Referring to a monad as a simple substance, he writes in a typical passage: “each simple substance is a perpetual, living mirror of the universe” (M 56). Although Leibniz’s mirror analogy is well-known, it is not well understood. Accordingly, the goal of my talk is to show how Leibniz’s mirror analogy can shed light on his monadic metaphysics. Unlike other commentators, my strategy is to draw on Leibniz’s writings on perspectiva because it is now clear that Leibniz had expertise in a branch of mathematics known as perspectiva and that his mirror analogy is based on his work in perspectiva.

My talk is divided into three parts. First, I outline a fact that Leibniz learned from perspectiva, which is that any point on a body can be projected onto a drawing in such a way so as to preserve its relations to other points on the body. I then claim that Leibniz took this fact to imply that there is an equivalence between a body and its perspectival representations. I close by sketching how this equivalence can make sense of Leibniz’s thesis that a body is an aggregate of monads.