One venerable form of virtue ethics—a form going back to Socrates, Plato, and Aristotle—gives primary theoretical place to eudaimonia. Eudaimonia is more or less happiness, but care is required here. We use happiness to mean many things, from the mood of the moment to a quality of life. What the Greeks have in mind with eudaimonia is much less like the former and much more like the latter. You might be happy in the sense of having a good life, even if just now you are not in a very good mood at all. It is that quality of life the Greeks call eudaimonia. When we wish a newly married couple every happiness, we are deploying the idea the Greeks intend with eudaimonia.

How does eudaimonia shape a virtue ethic? It provides the criterion by which we determine which dispositions or traits count as virtues. Those traits that contribute positively and significantly to our living happy lives count as virtues; vices are just those that do not. That does not mean that virtuous action is undertaken only for the sake of those happy lives; virtuous action has its own aims (on Aristotle’s view, always the “fine and noble”). Instead, the work of eudaimonia is criterial. We should not suppose such a criterion is easy to come by, or simple, or uncontested. An adequate account of virtues on such a view is a hard‐​won fruit of life and reflection. However, two members of any plausible such account—virtues that are invariably recognized as traits that contribute to a good human life—deserve discussion here, because they are crucial to what follows. They are practical wisdom (Greek: phronesis) and justice (Greek: dikaiosune). What needs explaining is how each contributes to a good life, and what specifically it requires.

Aristotle thinks of practical wisdom as the capacity to deliberate and act well about “what sorts of thing conduce to the good life in general.” 2 His argument for the centrality of practical wisdom to the good life starts with the kind of beings we are. We are, he argues, creatures who live our lives by deploying practical rationality. 3 We can, of course, deploy practical rationality in ways that do not conduce to good lives; only when we succeed in living well does what we do count as wisdom.

Other creatures live their lives in different ways. Giraffes live by grazing foliage that other herbivores cannot reach. Gazelles live by grazing grasses and by sprinting away from predators. Lions live by catching unwary or weak gazelles. Those forms of life are distinct and recognizable, the sorts of things we learn about in natural history museums. In the same vein, humans live by deploying capabilities that only we seem to have. We reason to plan and set ends, as well as to forge cooperative relationships with others of our kind. Aristotle’s fairly straightforward reasoning, then, is that if this is how we live, living well is a matter of deploying those capabilities well. It is excellence in practical reason, or practical wisdom. And excellence in practical wisdom, in turn, is understood as what successfully aims at living well. The two ideas must be understood in tandem.

The significance for us of practical rationality—and, when successful, practical wisdom—is reflected in the networks of ends that shape our lives. Ends are goals, and we can and do have innumerable ends. The resources necessary to realize them are scarce, so the enterprise of living a life of end seeking is one requiring continual and incessant judgment of tradeoffs. Some of the ends may be indeterminate, so that judgment is required even to know what successful pursuit of such an end would consist of. (When we marry, for example, we begin with only a hazy idea of what the end of a good marriage looks like. We find out what it means in detail only through being married—and through the course of innumerable judgments and experience.) Making those judgments well—in such a way as to live the kind of life we aspire to live—is what constitutes practical wisdom as a virtue. It is not easy, and it cannot be realized except by the application of practical rationality, with virtue of character, to our lives.

Practical wisdom has another important feature. Aristotle believes that we develop and maintain the virtues (or, sadly, the vices) by force of habit. Of course, we start with a moral education from our parents and teachers. None of us starts from ground zero, which is why it matters so much that we have a good start. We have passions and appetites, but—precisely because we have the capacity for practical rationality—as that capacity develops we can choose what we will do. And, importantly, there is a feedback loop here: the choices we make shape our passions and appetites. That is why habit is so important: as adults, this is how we shape who we become. So what we do makes us into what we are. What we become reflects the exercise of choice on our part; once more, the work of practical reason. We exercise choice not only in determining what to do but also in deciding what to be.

That we live by exercising practical rationality is obvious and important, but it is equally obvious and important that we live socially. Humans neither live nor thrive independently. We live with others of our kind. How we manage our relations with those others, then, is also centrally important to our living well. Many of the virtues of character bear on these relations, but none does so with greater import than justice.

The best understanding of the nature of the virtue of justice has, I believe, shifted somewhat since the early Greek theorists. Plato conceived of justice as “having and doing one’s own.” 4 Justice in the city (or polis) meant each kind of citizen performing his or her own task. Justice in the individual meant the rational, passionate, and appetitive parts of the psyche each playing its appropriate role. Aristotle saw justice as being more directly connected with action: he thought that the “narrow” sense of justice (that is, the sense in which justice is something more specific than just doing the right thing) could be understood in two ways. First, as a matter of proportionality: equals, he argued, deserve equal treatment, and unequals deserve unequal treatment. 5 Second, there is rectification: if I steal $100 from you, or make you $100 worse off, justice requires that my benefit be negated and that you be made whole. That is, justice requires that I give up $100, and you get it back.

It is hard to argue with those insights, but moral philosophy outside of virtue ethics has made progress in understanding what is due us in ways that, I believe, we should read into the virtue of justice. Consider slavery, a practice the ancients at least tolerated, if not (as in Aristotle’s case) outright endorsed. Slavery is manifestly unjust (however long it took humankind to come to that realization), and it seems that no just person would engage in slaveholding or tolerate its institutionalization. However (as Aristotle’s own case demonstrates), it is not clear how the justice of the ancient Greeks could show this. There would seem to be more to what the virtue of justice requires than Plato’s or Aristotle’s conceptions succeeded in capturing.

One way of putting what is missing is to say that the just person recognizes the moral standing of others in ways that rule out slavery. What exactly this moral standing might come to will be somewhat controversial, but there are core elements recognizable in our everyday practice.

One of those elements is rights and their recognition. Of course, people have legal rights, but those rights depend on the legal regimes they live under. We also have moral rights and entitlements. We have the standing to demand that others not do certain things to us—to enslave us, to harm us, in many cases to lie to us, to break faith with us, and so on. As Aristotle indicated, we have the standing to demand proportionality of various sorts in how we are treated (to be treated as we are due) and to complain if others treat us badly in various ways. To say that someone has rights is to say that he or she has a kind of standing that the just person ought to recognize.

A second (and not unrelated) element is accountability. Suppose you harm me; you strike me in the face. Now, the law might or might not have something to say about such an event, but we ordinarily think morality certainly does. A utilitarian might say that the problem with your doing so is that you fail to maximize the greatest utility. A divine command theorist might say that in doing so, you violate God’s law. But just left at that, even if either of those statements is true, it cannot be the whole truth. You have done something to me: you have wronged me. Crucially, you are accountable to me for the wrong you have done me. Any moral theory that leaves out the kinds of relations between us in which we are accountable to one another for the way we treat each other is inadequate. This kind of accountability is also a reflection of the standing that a just person should recognize others as having.

Finally, part of our moral standing is our capacity to change our moral relations with others in ways that reflect rights, obligations, and accountability. Consider, for example, our capacity to promise or to contract. If we make a deal that I will pick you up at the airport for $50, then each of us has conveyed rights to the other that we did not earlier have. I have a right against you that you pay me $50, while you have a right against me that I be there to pick you up when you arrive. Each of us is accountable to the other for doing what he or she has agreed to do. Each of us has those rights because (and just because) the other has given it. An important part of our moral standing, part of what the just person recognizes, is this capacity to change our moral relations with others in these ways.

All those elements and more are part of what we might call the “operational” aspect of being a just person. Many of its elements have been recognized since people first began theorizing about what it meant to be virtuous. Others have been more recently acknowledged. But at the core, there is more to being a just person than just these operational components, though it is certainly tied to those components. The just person sees others in a different way than the unjust person does. Consider the attitude of a human predator (perhaps a psychopath). To that person, humans are prey. To be sure, humans are importantly different from other possible prey: they have advanced rational capacities. They are (perhaps) better at detecting the kind of threat that a predator poses to them and are certainly capable of defending themselves against and perhaps retaliating against such a predator, with more force than any other potential prey. So the predator is wary of their capacities for reason and action. Their capacities figure into the predator’s reasoning only tactically or strategically as potential ways in which they might impinge on his efforts to get what he wants.

The just person whom we will call Socrates, conversely, sees others as having advanced rational capacities and more. But his regard for others is not merely tactical or strategic, as it is for the predator. Socrates sees others as sources of reasons and obligations, in the ways we have just surveyed and more, because of the kind of beings they are. Others matter to Socrates, we might say, for their sake, rather than for his sake. In Aristotle’s terms, the reasons Socrates has for regarding them are final—they are ends—rather than being merely instrumental to his own purposes. 6

I have claimed that practical wisdom and justice count as central and important virtues in the view we are exploring here, but also that what counts as a virtue is a matter of what contributes to our happiness. The importance of practical wisdom for happiness is evident: it consists in the capacity to use practical rationality effectively in living a good life. But what about justice? After all, many have understood the requirements of morality (and especially of justice) to amount to constraints on our pursuit of happiness. Why think that it is an important part of an account of the kind of virtue that contributes to happiness?

The heart of the response to this question lies with our essential sociality. We are not atomistic individuals; as Aristotle recognized, we thrive in the company of others of our kind. The relations we have with others not only concern how we provide for our material needs (as Marx focused upon) but also concern our relations with others as rational, planning agents, as beings who apprehend and act on reasons. Our relations with others include and occur within the “field” of those rational capacities. We have interests in the reasons that others provide us and that we provide them (we might call them “normative interests”). All of those dimensions of our social life have to go well for us to be happy, and they are the province of the virtue of justice. For us to thrive, we need to live in a network of recognition of others as having the kind of standing that constrains us from enslaving them, harming or lying to them, and so on. In other words, we need to see others in the way I have argued the just person sees others.

Consider an example (from philosopher T. M. Scanlon). Suppose you have a friend, someone you have until now considered a very good friend. But now (let us assume) you have some grave liver disorder, incurable, and you are in need of a transplant. And your friend tells you: “You and your friendship are so important to me that I will do anything to get you the liver you need. If I can’t find a donor, I will kill someone to get you that liver.” Something is clearly wrong with such a friend; indeed, you are likely not to consider him or her a friend, let alone a close friend, much longer.

The toxicity of that sort of injustice is incompatible with friendship. The wrongness of the way your erstwhile friend is willing to act will kill off the vital connections that we enjoy with others, connections that sustain our friendships and make our lives worth living. A bit of reflection will reveal that these sorts of sensibilities and forms of responsiveness underwrite every relation we have with other human beings. Unless we are living the kind of deformed human life that hermits live, justice is essential to happiness.

In summary, then, the kind of virtue ethic I have sketched—a eudaimonist virtue theory—maintains that we should aspire to be virtuous people. We should do so in order to live good lives, but the point is that the virtues are the keys to such lives. And although the list of virtues may itself be a matter of some contention, there is no plausible contention that among the most important elements of that list are practical wisdom and justice. So now, the question is, if that is all true, what is the connection to libertarian political theory? Why think that our political lives should be ordered as libertarians believe, if in fact such a virtue ethic is the right account of morality?