Leibniz’s Optics and Contingency in Nature

In the late 1670’s to early 1680’s, Leibniz came to hold that the laws of nature are paradigmatically contingent, that they provide the basis for a new argument from design, and that they presuppose the existence of active, goal-directed powers reminiscent of Aristotelian entelechies. In this essay, I argue that the standard view according to which Leibniz forges these signature theses in the domain of physics and opportunistically carries them over to the domain of optics gets things essentially the wrong way around. The crucial nexus of views at the heart of Leibniz’s mature philosophical understanding of the laws of nature has its most intelligible roots in his optical derivations, which appear to have paved the way—both historically and conceptually—for the philosophical significance he assigns to his discoveries in the domain of physics. Optics the horse, as it were, physics the cart.