HPS Colloquium: Robert Goulding:


Location: 116 O'Shaughnessy

"The Harvest of Optics: Descartes, Mydorge, and their Paths to a Measure of Refraction"

In my talk, I will present the argument of an article currently under review, concerning the early optical work of Descartes. In 1637, Descartes published his famous "tennis ball" demonstration of the sine relationship for determining the measure of refraction (what would later be termed the "law of refraction"). In the same work, the Dioptrique, he showed that hyperboloidal and ellipsoidal lenses were anaclastic -- that is, they focused parallel light rays perfectly to a single point. Descartes gave no indication of how or when he had discovered these results. In my paper, I consider the evidence for Descartes' research on optics in the 1620s, especially a small manuscript treatise on optics written by his erstwhile collaborator Claude Mydorge. This evidence, taken as a whole, strongly suggests that Descartes' crucial optical discoveries were equally the work of Mydorge and Isaac Beeckman, and had originally been conceived very differently from the explanation he gave in the Dioptrique. Stepping back from the particular historical episode, I hope that we can use this example to discuss the pitfalls of reading historical documents in isolation, and the necessity of embedding them in as rich a contextual framework as possible.