A different descartes: Descartes and the programme for a mathematical physics in his correspondence

The seventeenth century was the period in which mathematical physics as we know it was invented, in which �?gures like Galileo, Huygens, and Newton learned to apply mathematics to physical problems. Descartes would seem to have been well placed to participate in this important movement of thought. He was one of the pre-eminent mathematicians of the century, and his Géometrie one of the great works in the history of mathematics. He wrote extensively on questions in physics, and his mechanistic vision of the world was deeply influential on his contemporaries, perhaps even more so than even his metaphysics. Indeed, his identi�?cation of body and extension would seem to guarantee that he would have to be a mathematical physicist; for him, bodies are just the objects of geometry made concrete. It is not surprising, then, that any number of times he declared that his physics is just mathematics. For example, in the Principia, Descartes writes: The only principles which I accept, or require, in physics are those of geometry and pure mathematics; these principles explain all natural phenomena, and enable us to provide quite certain demonstrations regarding them.1.