I’ve been thinking a bit more about Usener’s supplement to Kyria Doxa 5. It concedes that someone might like justly but not wisely. In that case he will not live a pleasant life however just his life is. On this view, the Epicureans do not take the paradoxical line preferred by the Stoics and other philosophers in the Socratic tradition of arguing that only the wise man will be truly just. Their account of the virtues is different in so far as it is primarily concerned with accommodating the virtues into their picture of the best life rather than appropriating them as the Epicureans’ sole property. If to live justly is simply to act in certain ways, obey the law, respect one’s neighbours’ possessions and so on, then it certainly is not the case that only the Epicurean will live justly. Hence the statement in Kyria Doxa 5 that someone might well live honourably and justly (but not pleasantly) while lacking the practical wisdom that is the root of the Epicurean’s choices. Other people can be said to live justly, to display temperance, or to fight and die courageously. And it might suit the Epicureans very well to prefer this rather thin account of what it means to live in accordance with a particular virtue since then they will be better able to say that an Epicurean too will meet the relevant criteria for living justly and honourably . However, they will go on to say that the Epicurean will live in such a virtuous fashion as part of his general programme of living so as best to attain his natural final good and his living justly and so on will be a consequence of the application of his prudential reasoning to matters of choice and action. So an Epicurean will act consistently in these ways because his acting justly, for example, flows from a deep-seated and basic commitment to the principles of the hedonic evaluation of possible choices.
None of this should be taken as a defence of Usener’s construal of Kyria Doxa 5. There are clearly sufficient textual difficulties with this part of Kyria Doxa 5 to make us wary of basing any significant claims about the Epicureans’ attitude to the virtue on any proposed reconstruction or emendation of the text. Nevertheless, it is not obvious to me why the Epicureans would need to claim that only the Epicurean wise man is just and this is something they perhaps ought be inclined to jettison if needed. In the case of piety, for example, they do have a clear and distinctive positive message to convey that would lead them both to dismiss the charge of atheism and make the controversial claim of sole possession of that virtue. But there is less pressure for them to take such a stand in the case of the other virtues bar wisdom. And conceding that someone might succeed in living justly, for example, simply by living in accordance with certain rules of interpersonal behaviour might well make more palatable their claim that an Epicurean hedonist will in fact live justly at all.