Genèse et évolution du principe de raison suffisante dans l’oeuvre de Leibniz

In its first section, this study aims at identifying the sources which Leibniz refers to in order to establish the principle of reason. Five main traditions come out: first the tradition of the “Regula Platonis”, then the one of the “topica aristotelica”, that of the Stoics “de Fato” and of the “Chrysippus milieu”, also the Christian one through the “Johanical formulation”, and finally that of the Moderns that Leibniz encountered during his academic and scientific education. In the second section, we have studied the evolutions of the formulations of the principle of reason. Five phases can be distinguished : phase 1 (1663-1677) in which Leibniz defines the fields of the sufficient reason ; phase 2 (1678-1685) in which he establishes the principles of the truths ; phase 3 (1686-1696) in which he coins the « principium reddendae rationis » ; phase 4 (1697-1706) in which he coins the « principle of the sufficient reason » and phase 5 (1707-1716) in which the principle of reason becomes a principle of defence of the “causa dei” and of metaphysics.