The Nature of Things and the Nature of Mind: Reflection, Intelligibility, and Leibniz’s Case Against Materialism

Leibniz’s claim that it is possible for us to gain metaphysical knowledge from reflection on the self has intrigued many commentators, but it has also often been criticized as flawed or unintelligible. A similar fate has beset Leibniz’s arguments against materialism. In this paper, I suggest that both of these assessments are in need of reconsideration. By examining in depth one of Leibniz’s lesser-known arguments against materialism, I show that it provides us with an instance of a Leibnizian “argument from reflection”, which – far from being flawed – is in fact securely grounded in the Principle of Intelligibility, a corollary of the Principle of Sufficient Reason which lies at the heart of Leibniz’s system.