Marin Mersenne (1588–1648) was a Friar Minim. Although he contributed almost nothing in the way of his own ideas, he played a pivotal role as facilitator and publicist for the modern philosophy. He was Descartes’ closest associate. In the extracts below, Descartes discusses further the reason for choosing the pineal gland as the seat of the soul.

The letters are written in French, and I have translated them from Adam and Tannery Volume III, to which the page numbers in square brackets refer.

Go to Index to Correspondence with Mersenne