Introduction

The Monadology is the philosophical summary Leibniz wrote for a friend in his last years; it has only ninety sections, yet it condenses his whole system. The universe is made of countless 'monads', simple spiritual substances without parts or extension, which 'have no windows through which anything could come in or go out' and do not act on one another; each mirrors the whole universe from its own point of view, as a city looks different from every side. The harmony among monads was established by God at the creation; this is 'pre-established harmony'. From this he draws his famous conclusion that ours is the best of all possible worlds. With it is the earlier Discourse on Metaphysics, his first systematic statement of his philosophy.