1638-1715. French Catholic philosopher. He entered the Oratorians* in Paris (1660) where he remained throughout his life. He was ordained priest (1664). His philosophical work concentrated on the relation between faith, reason, and empirical observation, seeking therein to find an accommodation between Catholicism and Cartesian philosophy. De la recherche de la vérité (2 vols., 1674-75), Traité de la nature et de la grace (1680), and Entretiens sur la métaphysique et sur la religion (1688) are his greatest works and embroiled him in constant polemics, with Bossuet, Leibnitz, Fontenelle, and many others. As a scientist he studied insects, mathematics, and color; simultaneously he was a méditatif in the Oratory.
He agreed with Descartes that we do not perceive the actual physical objects, such as the sun; they are mediated to us via idées in our minds. Against Descartes, however, he claimed such idées are archetypes of objects in the mind of God. We are assured that the actual objects do exist by supernatural revelation which we accept on faith. This notion is termed the “vision in God.” Concerning causation in the physical world, he postulated “occasionalism” by affirming that God, acting through his general laws of motion, is the true cause of all motion (i.e., causing a ball to move), while particular or occasional causes (i.e., a ball striking another ball causing it to move) exist.