The Passions of the Soul

Descartes's last published work, a treatise in short numbered articles that grew out of his letters with Princess Elisabeth of Bohemia, who had pressed him on how mind and body interact and how to master the emotions. Part One describes the body as a machine moved by 'animal spirits' and locates the main seat of the soul's interaction with the body in the pineal gland. It defines the passions as perceptions or emotions of the soul caused by the motion of these spirits, and argues that the will can govern them only indirectly, by redirecting attention and habit. Part Two names six primitive passions, wonder, love, hatred, desire, joy and sadness, and traces their bodily signs and uses. Part Three derives many particular passions from these and gives a central place to generosity: the proper self-esteem of one who knows that only his free will is truly his own and resolves to use it well, which Descartes calls the remedy against disordered passions.

It is the fullest early modern account of the emotions as both bodily and mental, and its idea of generosity gives Descartes an ethics that readers of the Meditations rarely see.