The "Ethical Trespass" of Botany: Remarks on the Stoic Extension of Proper Functions (Kathekonta) to Plants

Résumé En

The topic of my paper is the idea that the Stoic concept of kathēkon concerns plants. This doctrine, attested, though unexplained, by Diog. Laert., 7.107, is apparently unparalleled in the other sources. This doesn’t seem odd, since kathēkonta pertain to ethics. So far, the scholarship has shed little light on this encroachment of botany into ethics. The main achievements in this regard are intuitions about what sort of things, and why, Stoics would call ‘plant kathēkonta’. However, they are seldom based on an assessment of the place of plants within Stoic philosophy, nor on examples of plant kathēkonta found in ancient sources. It is precisely by understanding how the Stoics conceived plants and by detecting illustrations of their “proper functions” that I shall try to answer this puzzle. I thus conclude that plant kathēkonta are processes granting plants to live healthy and whose label as kathēkonta finds justification within the doctrine of oikeiōsis. These findings have a backlash on our understanding of the relationship between Stoic physics and ethics, usually grasped in terms of a natural foundation of morality. Contrariwise, the case of plant kathēkonta shows that this relationship is more complex: physics and ethics sometimes concur to shape a single concept, which is thus poised between different domains. Another significant outcome concerns the Stoics' use of plant kathēkonta as a model for the virtuous conduct.