Leibniz’s Formalist Epistemology of Necessity

Developing a theme from Margaret Wilson’s work on Leibniz’s theory of truth, this paper examines how Leibniz conceives of our knowledge of necessary truths against the backdrop of the radically different theoretical framework he inherits from Descartes. I argue that Leibniz, in contrast to the intuitionist account of Descartes and his followers, defends a thoroughly “formalist” conception of such knowledge: While the Cartesian view is built on our immediate, intuitive grasp of the ideas a proposition involves, Leibniz’s account involves an analysis of the proposition’s formal structure. My goal is to bring out both the historical as well as the systematic significance of this difference. Systematically, Leibniz’s formal conception appears to give his theory a crucial epistemological advantage over Descartes’ intuitionist account: While Descartes in the end is merely able to appeal to our introspective feeling to account for the certainty of necessary truths, Leibniz’s account provides us with a more substantial criterion to account for their certainty, based on his claim that the Principle of Identity is the logical foundation for all necessary truths. Historically, Leibniz’s account of our knowledge of necessary truths dissociates the certainty of such truths from an appeal to divine goodness, instead grounding them in the claim that human reason is a direct reflection of the divine intellect. His view thus marks an important shift in how the relation between human and divine intellect is conceived.