Climbing the Tree of Philosophy? Physics, Medicine, and Morality in The Passions of the Soul
In this paper I aim to identify, disentangle, and relate physical, medical, and moral perspectives on the role of the passions in human life. In one of the prefatory letters to the The Passions of the Soul, Descartes’ “physics” (which includes the study of plants, animals, and humans) is presented as especially relevant to medicine—one of the three principal “branches” of philosophy that sprout from its “trunk” (physics), to employ Descartes’ image of the Tree of Philosophy (also referenced in the prefatory letters of Passions). The other two branches in Descartes’ Tree are mechanics and morality. By the latter, Descartes means “the highest and most perfect morality, which presupposes a complete knowledge of the other sciences and is the final stage of Wisdom.” Although in the last prefatory letter Descartes says that he treats the passions as a “physicist”, The Passions of the Soul clearly employs both moral and medical perspectives. This is reflected variously throughout, and especially in a series of parallel passages treating the use of the passions. My attention will focus on teasing apart the physical, medical, and moral character of and grounds for claims in these passages. One interpretive goal is to show that Descartes need make no appeal to “robust” natural teleology in his physical and medical sciences of the human being.