ABSTRACT
In 1637, Descartes published, along with his Discourse on Method, his treatise Optics, which was to illustrate his new scientific method. It aimed to provide geometry of vision, in which the study of light would account for human perception of objects. Light, with its refractions and reflections, passes immediately from the object via the lenses of the eye to the retina:
the light in the bodies we call luminous is nothing other than a certain movement, or very rapid and lively action, which passes to our eyes through the medium of the air and other transparent bodies, just as the movement or resistance of the bodies encountered by a blind man passes to his hand by means of a stick.
(Descartes 1988, Vol. 1: 153) For Descartes, the full explanation of perception and light will involve more than physiology, for ‘it is the soul which sees, not the eye, and it does not see directly, but only by means of the brain’ (ibid.: 172; cf. Cottingham 1993: 110). Nevertheless, it is light that is the ‘direct touch’ between the object and subject of vision (cf. the metaphysics of presence in Chapter 1).