Leibniz’s claim that it is possible for us to gain metaphysical knowledge through 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 explore one of Leibniz’s lesser-known arguments against materialism from his reply to Bayle’s new note L, and argue that it provides us with an instance of a Leibnizian “argument from reflection”. This argument, I further show, (...) does not constitute a flawed appeal to mere introspection, but is in fact securely grounded in an important corollary of the Principle of Sufficient Reason: Leibniz’s Principle of Intelligibility. (shrink)

I propose a straightforward reconciliation of Leibniz’s conception of bodies as aggregates of simple substances (i.e., monads) with his doctrine that bodies are the phenomena of perceivers, without in the process saddling him with any equivocations. The reconciliation relies on the familiar idea that in Leibniz’s idiolect, an aggregate of Fs is that which immediately presupposes those Fs, or in other words, has those Fs as immediate requisites. But I take this idea in a new direction. Taking notice of the (...) fact that Leibniz speaks of three respects in which one thing may immediately presuppose others--i.e., with respect to its being, its existence, and its reality--I argue that a phenomenon having its being in one perceiving substance (monad) can plausibly be understood to presuppose other perceiving substances (monads) in two of these respects. Accordingly, good sense can be made of both the claim that a phenomenon in one monad is an aggregate of other monads (in Leibniz’s technical sense of 'aggregate') and the (equivalent) claim that the latter monads are constituents of the phenomenon (in his technical sense of 'constituent'). So understood, the two conceptions of body are perfectly compatible, just as Leibniz seems to think. (shrink)

The defense of common sense in Berkeley's Three Dialogues is, first and foremost, a defense of the gardener's claim to know this cherry tree, a claim threatened by both Cartesian and Lockean philosophy. Berkeley's defense of the gardener's knowledge depends on his claim that the being of a cherry tree consists in its being perceived. This is not something the gardener believes; rather, it is a philosophical analysis of the rules unreflectively followed by the gardener in his use of the (...) word 'exists'. It is by following these rules that the gardener gains knowledge of the cherry tree. Uncovering these deep connections between Berkeley's epistemology and his philosophy of language and placing them in the context of his critique of both Cartesian and Lockean philosophy will clarify Berkeley's strategy for bringing his reader back to common sense and practical engagement in the ordinary affairs of life. (shrink)