 In 1880, he collaborated with Émile Boutroux on the edition of Leibniz’ Monadology, providing an article comparing the physics of Descartes and Leibniz. It was not until the 1890s, however, that he became a central actor in the French philosophical scene, notably through his continuous involvement in the Revue de métaphysique et de morale (in which he published some twenty articles) and his participation in the organization of a large number of events: the celebration of the centenary of the birth of Descartes, the International Congress of Philosophy of 1900, and the international edition of the works of Leibniz.