The year 1996 marked the quattrocentenary of Descartes' birth. This paper reviews his pineal neuropsychology. It demonstrates that Descartes understood the true anatomical position of the pineal. His intraventricular pineal (or glande H) was a theoretical construct which allowed him to describe the operations of his man-like "earthen machine." In the Treatise of Man he shows how all the behaviors of such machines could then be accounted for without the presence of self-consciousness. Infrahuman animals are "conscious automata." In Passions of the Soul he adds, but only for humans, self-consciousness to the machine. In a modern formulation, only humans not only know but know that they know.
Copyright 1998 Academic Press.