Lambert on Eternal Truths and the Existence of God

In Lambert's "Neues Organon", the doctrine of the suppositum intelligens is inextricably linked to one of the most controversial issues of post-Cartesian metaphysics: the doctrine of eternal or necessary truths, which was still intensely debated by eighteenth-century German philosophers. In Lambert’s work, however, this doctrine appears to be relegated to the margins, along with all other theological concerns. Its rather infrequent mentions in both the Neues Organon and the Architectonic can strike the reader more as residues of earlier debates than serious investigations of a current topic. In the earlier essay "Über die Methode die Metaphysik, Theologie und Moral richtiger zu beweisen", by contrast, eternal truths indisputably play a prominent role. Their existence is the pivot of Lambert’s main argument to the effect that even rational theology can attain the degree of perfect certainty that is already enjoyed by geometry and logic. Starting from an analysis of "Über die Methode", I argue that the theological implications of the doctrine of eternal truths remain decisive for Lambert even in the "Architectonic". In particular, the development of this doctrine provides essential clues to understanding Lambert’s theory of modalities and its radical departure from Wolff’s modal framework.