Sensory Mechanics: Model of Sensation in Descartes’ Principles of Philosophy

Abstract

This article undertakes a critical examination of Descartes’ theory of sensation as presented in his Principles of Philosophy. The analysis identifies the key ontological and epistemological aspects of his account in relation to Descartes’ treatment of qualities: the problem of psychophysical interaction and the tripartite model of sensation implied by Cartesian ontological dualism; the requirement to explain the diversity of sensations through a restricted set of mathematical and kinematic properties and, ultimately, through the motor potential of the nerves; and, finally, the conception of sensory content as determined solely by external objects, together with the associated notions of monocausality, the receptivity of sensory perception, and the objective basis for distinguishing between primary and secondary qualities. These considerations are preparatory in character – their aim is to lay the foundations for a more comprehensive analysis of the Cartesian distinction between these two types of qualities.