De Roy, Henri

(also known as Regius). Born June 29, 1598, in Utrecht; died there Feb. 17, 1679. Dutch materialist philosopher, physiologist, and teacher. De Roy championed the mechanistic physics and physiology of Descartes but rejected his dualist metaphysics (Fundamenta physices, 1646; Explicatio mentis humanae … ., 1647). He declared that the soul is only a modus (property) of the body and attacked the doctrine of innate ideas, allowing only the existence in the soul of an ability to think. Anticipating the ideas of Hobbes, de Roy connected mechanistic physiology with the doctrine of the experimental, sensory origin of all ideas. In his systematic outline, Philosophia naturalis (1654), de Roy strongly emphasized physics, which in his opinion, in contrast to Descartes’s is prior to psychology and the theory of knowledge.