Descartes began his Optics of 1637 by proclaiming his enthusiasm for the telescope. ‘Since sight’, he wrote, ‘is the noblest and most comprehensive of the senses, inventions which serve to increase its power are undoubtedly among the most useful there can be’ (1988: 57). And what more wonderful invention could one imagine than the telescope, which has so enhanced the power of sight as to open up whole new vistas for the human understanding of nature and the universe? In according pride of place among the senses to vision, Descartes was following in the footsteps of a long line of philosophers, reaching back to Plato and Aristotle.8 Despite continuing doubts concerning the reliability of sight, as opposed to hearing, the superiority of both vision and hearing over the so-called ‘contact’ senses of touch, taste and smell was never in question. So far, I have had nothing to say about the latter. Taste and smell raise a whole gamut of problems of their own which lie beyond my present concerns, and while I admit that they would have to be included in any discussion of human sensory experience that claimed to be truly comprehensive, I do not intend to deal with them further here. But I can no longer put off some consideration of touch. For in treatments of perception in the Western philosophical tradition, it is above all to touch rather than hearing that sight has been compared. And in this, Descartes was no exception. Indeed it was through an analogy with touch that he chose to introduce the workings of vision.