Descartes then took a law degree at Pottiers and set off to complete his education by travel in Europe. He wrote that he had resolved “to seek no knowledge other than that which could be found either in myself or the great book of the world.” He served briefly in the army and then became friends with Isaac Beeckman (1588–1637), a Dutch philosopher and scientist who inspired him to study mathematics.

Descartes’ first book, Compendium Musicae, applied mathematics to harmony and dissonance. Descartes also began work on his discovery of analytic geometry that was published in 1637.

On November 10, 1619, Descartes spent many hours sequestered in a room-sized stove in a town in southern Germany. (Such very large stoves with shelves, places to sleep, and room to stand up in them were built in Germany and Russia, until the end of the nineteenth century.) Descartes had an epiphany as the result of three bizarre dreams, which set him on a course to create a new system for science and philosophy.

His inspiration was that, beginning with a few ideas known to be absolutely true, and careful methods of reasoning with them, the basic principles of all of the sciences could be logically derived from those ideas.

Descartes would go on to live briefly in Paris in 1628, before moving to Holland, where he was to remain for the rest of his life.