Treatise on Man

What it is

Treatise on Man (L'Homme) is an unfinished work by René Descartes, begun in the 1630s and published after his death, first in Latin in 1662 and then in French in 1664, edited by Claude Clerselier with added diagrams and commentary by others.

Why it matters

Descartes describes a human body as a kind of machine, explaining digestion, blood circulation, nerves and the senses in mechanical terms, with the pineal gland playing a key role. He held the work back after learning of Galileo's condemnation by the Inquisition, fearing similar trouble for his own ideas. The book shows how political and religious pressure could silence even bold scientific thinking, and how later editors like Clerselier, La Forge and Schuyl shaped how Descartes' ideas reached the public.

Look closer

• Why might Descartes have chosen not to publish this work during his lifetime?
• What does describing the body as a "machine" suggest about how Descartes viewed humans?
• Who added to this book after Descartes died, and how might that change how we read it?