 In 1693, Malebranche responded to the criticisms of the Recherche in the 1690 Systême de philosophie (System of Philosophy) of the French Cartesian Pierre-Sylvain Régis (1632–1707). Régis had defended an account of ideas similar to the one that Arnauld had defended against Malebranche during the 1680s, and Arnauld used the Régis-Malebranche exchange as an occasion to return to the issue of ideas during the last year of his life. Despite their dispute, Malebranche and Régis were both appointed as honorary members of the Paris Académie des sciences when it was reorganized in 1699. Malebranche presented an inaugural lecture to the Académie that defends against Descartes an account of color in terms of the frequency of vibrations of light. In later published versions of the lecture, Malebranche revised his discussion to take into account the theory of the nature of color in the work of Sir Isaac Newton.