Abstract

Leibniz's version of the ontological argument, a modal argument for theism on which he worked most intensively in the 1670s, has two stages. The first, an “incomplete” proof, concludes that God can only be a necessary being, and therefore if God's existence is possible, then God exists. The second stage is an a priori argument that the existence of such a necessary God is indeed possible. Leibniz's fullest attempts at a possibility proof turn on his conception of a most perfect being, and the chapter concludes that they are not likely to succeed, in part because of difficulties in connecting the concepts of perfection and necessary existence.