Conversation so far:
What was one of René Descartes' philosophical writings?
The Passions of the Soul
Did the theory of psycosomatic processes by René Descartes become popular?
René Descartes' works would have a lasting impact on ideas concerning what literature and art should be, specifically how it should invoke emotion.

Question: How did he arrive at this conclusion?
Self-contained rewrite: How did René Descartes arrive at this conclusion?