Descartes’ Optics and the early modern posthuman

ANDRÉS VACCARI

Macquarie University, Sydney

Conferencia; Australasian Postgraduate Philosophy Conference; 2004

Australasian Association of Philosophy

In this paper I argue that Descartes’ project anticipates one of the features of posthuman culture, namely the blurring of the distinction between the artificial and the natural, machine and organism, and instrument and organ. I examine this close amalgamation in the context of the Optics. Descartes’ ambition is to combine two related approaches to natural philosophy, the geometrical and the micromechanical. Both have a degree of autonomy, but are perfectly complementary. The machine analogies clearly help us picture the micromechanical. Descartes’ theory of vision is the clearest example of these two dimensions of explanation, inasmuch as they are the only place in L’homme where geometrical diagrams are employed. Part of Descartes’ account of vision is geometrical, and part is mechano-metaphysical. Rays of light are rectilinear tendencies to motion transmitted through the plenum and reaching the eye, where they are refracted and refocused into points of pressure that trace patterns on the retina at the back of it. Here, lines and figures are applied to the modelling of physical effects. Light rays are (geometrically speaking) straight lines that (physically speaking) don’t exist, but arise from tendencies to motion traversing the plenum.