The Invention of Duty: Stoicism as Deontology

Abstract

Philosophers today generally believe that duty-based (deontic) ethics was an innovation of the Enlightenment, spearheaded by the work of Immanuel Kant in particular. According to this prevailing scholarly opinion, while the ancient Greeks and Romans had notions of civic, military, and religious duty, they lacked a notion of purely moral duty as well as a duty-based system of ethics. In this dissertation, I argue that the ancient Greek and Roman philosophers of the Stoic school did in fact develop a notion of moral duty as well as a sophisticated, deontic ethical theory built around that notion. The deontic aspect of the Stoic system has hitherto gone unnoticed for a number of reasons, including the paucity and fragmentary nature of the extant evidence from early Stoic writers. Throughout the first three chapters of my thesis, I try to piece together the surviving evidence in order to reconstruct the Stoic theory of duty.

In the first chapter, I argue that the important Greek term καθῆκον (kathêkon), which the Stoics coined and which recent scholars have assumed means “appropriate action,” actually means something like “required/prescribed action” and approximates our notion of “duty.” I do this through a detailed philological study of the earliest surviving texts in which either the term itself or the verb from which it was derived (καθήκειν) appears. My second chapter argues that, while the Stoics spoke of (morally) “prescribed actions,” they rejected all fixed rules of conduct on the grounds that no rule – no matter how carefully formulated – can be without exception. My third chapter attempts to explain how, in lieu of a set of rules, the Stoics offered a kind of formula by which every rational agent can calculate his/her precise duty in any given situation. The fourth and final chapter explores the various avenues through which Stoicism influenced Kant and offers a comparison of Stoic καθῆκον with the Kantian concept of duty.