I. Introduction
One of the central claims of Plato’s Republic is that justice is not only desirable for its own sake, but that it maximises the happiness of those who practice it. This paper examines Plato’s arguments in support of this thesis to determine (a) what he means by happiness, (b) to what extent it exists in his proposed ideal state, and (c) whether this in any way substantiates his claims about the benefits of justice. In particular, I will argue that there are two different conceptions of happiness at play in The Republic, and two methods of achieving its highest form, namely the pursuit of justice and philosophy, before arriving at a final definition of the Platonic Form1 of happiness—a matter that Plato touches on only briefly in the text, but that is nevertheless central to his thinking on the subject.
II. Happiness and Pleasure
I will begin by considering the distinction between happiness and pleasure, and the language that Plato uses to describe the two. The word used most often in the text to describe happiness is eudaimonia, which may also be translated as ‘flourishing’ (Vlastos: 108). In contrast to the English word ‘happiness’, this suggests a ongoing process or activity, rather than a particular state of mind or emotion. However, it would be a mistake to read too much into this linguistic distinction as Plato uses eudaimonia more or less interchangeably with ‘pleasure’ (hēdonē), and it carries the same hedonistic connotations (ibid.). Unlike ‘happiness’, however, eudaimonia can be ascribed both to the state and the soul (psychē)2 in accordance with the central thesis of The Republic that these two entities share a common structure. Indeed, Socrates states several times that societal flourishing is more important than the happiness of any individual class or citizen (420b–421c, 519d–521a),3 implying that personal happiness is a means to an end rather than an end in its