Pierre-Sylvain Régis was a student of the Cartesian physicist Jacques Rohault. Like Rohault, Régis expounded Cartesianism in public lectures. In 1680 François de Harlay de Champvallon, the archbishop of Paris, told Régis that King Louis XIV forbad public lectures for fear of uproar concerning the Cartesian explanation of transubstantiation. Régis continued to give private lessons, and by 1699 the conflict over Cartesianism had subsided, leading to his admission to the Academie des Sciences, along with Nicolas Malebranche, whose occasionalist philosophy was a response to problems of Cartesian dualism.

Régis's system is based on fourteen self-evident metaphysical principles derived from the cogito (Descartes' basic axiom: "I think, therefore I am").

(1) All properties belong to something, that is, nothing can have no properties

(2) All effects presuppose causes

(3) An effect can have no more perfection than does...