Descartes dedicated an entire work to the study of the passions: Les passions de l’âme (1649) investigates the tight connection that spans from the occurrence of mechanical processes in the human body to the emergence of feelings and thoughts in the soul. By writing a treatise on the passions, on the one hand, Descartes wants to approach the topic as a natural philosopher, that is, as someone who studies the realm of nature in which bodies behave in accordance with the principles of cause and effect (AT 11:326, CSM I 327). 1 Passions are here treated as physiological events that depend in their production and maintenance on the dynamics of the particles of the blood—Descartes’ animal spirits—and the nerve structure of body and brain (AT 11:349, CSM I 339). On the other hand, Descartes wants this work to serve his readers as a manual suitable for the control of the passions, affective drives, and appetites. 2