Leibniz and the Proof of God’s Existence from Eternal Truths

The aim of this article is to show how and in what stages G. W. Leibniz came to develop his proof of God’s existence from eternal truths. It begins by tracing the main stages in the history of this proof, initially forged by Augustine of Hippo, and discusses the reasons for its renewal in the last quarter of the 17th century in the post-Cartesian context. The article then shows why, despite skepticism towards this proof in his youth, Leibniz finally produced a version of it that he presents in the <i>Monadology</i> even before the ontological proof. My hypothesis is that the development of the proof from eternal truths is directly linked to Leibniz’s reflection on the nature of the possible, a reflection that is itself to be placed in the context of the polemic between Nicolas Malebranche and Simon Foucher after the publication of the <i>Search after Truth</i>. The Leibnizian proof is original in that it rests on the consideration of the reality of possibles, insofar as God is the reason for them, and on the claimed subordination of logic to ontology.