For Aristotle, writing in Athens in the fourth century BCE, the question "what is happiness?" was the starting point of ethics. His Nicomachean Ethics opens by noting that every action aims at some good, and that some goods are pursued for the sake of others. Aristotle argued that the highest good is eudaimonia, the one thing chosen always for its own sake and never for the sake of anything else. We seek honor, pleasure and wisdom partly for themselves, he said, but also for the sake of eudaimonia; no one seeks eudaimonia for the sake of honor.

Not a feeling

Eudaimonia is usually translated "happiness," but many scholars prefer "flourishing," because Aristotle meant a way of living, not a mood. The word joins eu, well, with daimon, a guardian spirit, and in ordinary Greek it meant being blessed or fortunate. Aristotle made it something you do. It can be assessed only across a whole life.

The function argument

To find out what flourishing consists in, Aristotle asked about function. A flute player, a sculptor and an eye each have a characteristic work, and doing it well is what makes them good of their kind. What is the characteristic work of a human being? Not mere life, which we share with plants, nor perception, which we share with animals, but the activity of the soul in accordance with reason. A good human life, then, is that activity done excellently, which means in accordance with virtue. Aristotle added a condition: in a complete life. In W. D. Ross's 1925 translation: "For one swallow does not make a summer, nor does one day; and so too one day, or a short time, does not make a man blessed and happy."

Critics have long questioned the function argument. Why should what is distinctive about humans be what is best for them? Defenders reply that Aristotle meant our capacity for reasoned choice, which can be exercised well or badly, and that exercising it well is just what we mean by living well.

Three lives

Aristotle reviewed the lives people commonly think happy. The life of pleasure he called fit for grazing cattle, since it misses what is distinctively human. The life of politics aims at honor, but honor depends on those who give it, while the good should be something our own. The life of study, or contemplation, he ranked highest at the end of the work, since it uses our best capacity and is the most self-sufficient. Readers still argue over how that ranking fits his long praise of the active virtues.

Luck and external goods

Unlike some later thinkers, Aristotle did not think virtue was enough. A flourishing life also needs external goods such as friends, health, some wealth and decent standing, because many fine actions require resources, and because some misfortunes spoil happiness. He pointed to Priam, the king of Troy, who was prosperous and good but in old age saw his sons killed and his city fall. No one, Aristotle said, calls such a man happy. So great misfortune can spoil a good person's happiness, which gives luck a role in the good life that the Stoics would later deny.

Aristotle also took friendship seriously as part of flourishing, devoting two of the ten books of the Ethics to it. He held that humans are social and political by nature, so a solitary life, however comfortable, would lack something essential.

Strengths and worries

Aristotle's view has had a revival. It explains why a pill-induced glow seems hollow and why a life of real activity and friendship seems good even when it is hard. Psychologists such as Carol Ryff have built scales of eudaimonic well-being that measure things like personal growth and purpose in life alongside mood.

The worries are real too. Aristotle believed some people were slaves by nature and that women's reasoning lacked authority, so his own picture of who could flourish was narrow. Modern Aristotelians reject those views as inconsistent with every person's capacity for reason and choice. A second worry is that tying well-being to virtue confuses being good with doing well: could a bad person not have a life that goes well for him? Aristotle would say no, which many find too neat.

Worked example: two careers

Sana and Theo are doctors. Sana works long hours in a rural clinic. She is often tired but uses her skill fully, keeps close friendships and is known for good judgment. Theo works fewer hours in a cosmetic practice, earns more and spends his free time on comfortable pleasures, though he admits the work bores him. On a mood survey this week, Theo might score higher.

Aristotle would ask a different question: whose life, taken whole, shows excellent reasoned activity, with the friends and resources that support it? On that question Sana may flourish more. But Aristotle would also want to know whether her exhaustion is wearing down her health, an external good she needs, and whether Theo's comfort leaves his best capacities idle. Flourishing, on his account, is excellent activity sustained over a lifetime, not the score on any single day.