Aristotle's Nicomachean Ethics

Aristotle asked what the good life actually is — and answered with habit, the mean between extremes, practical wisdom, and friends. The book has not aged.

The Nicomachean Ethics — named for Aristotle's son Nicomachus, who likely edited the lecture notes — is the West's first sustained attempt to treat ethics as an empirical subject. Not a sermon on what you ought to do, but an investigation into what it is for a human life to go well. Aristotle is patient, almost scientific. He gathers what people say, sifts the disagreements, and works toward an account that does justice to ordinary experience without flattering it.

Two and a half thousand years later, what he wrote still cuts. Four ideas, in particular, deserve the long second look.

Eudaimonia and the function argument

Aristotle begins with a simple observation. Every craft, every action, every choice aims at some good. We want money for the sake of what it buys. We want what it buys for the sake of pleasure or comfort or status. Those, in turn, we want for the sake of something further. The chain of for-the-sake-ofs cannot run forever; there must be something we want for its own sake, never as a means. That terminus — the good that all other goods point toward — he calls eudaimonia.

The word is usually translated “happiness,” but that is misleading. Eudaimonia is not a feeling. It is closer to flourishing, or a life going well, viewed whole. You cannot tell from a single afternoon whether someone is eudaimon, any more than you can tell from one move whether a chess game is being won.

But what does flourishing consist of? Aristotle's answer, the famous function argument, is bold. A knife is a good knife if it cuts well — if it does its characteristic function excellently. A flautist is a good flautist if she plays well. There must, then, be a characteristic function of a human being. Not nutrition or growth (plants do that), not sense-perception (animals share it), but reasoned activity. The good for a human, therefore, is activity of the soul in accordance with reason — and, if there are several virtues, in accordance with the best and most complete of them, over a complete life.

Virtue as the mean

If the good life is activity in accordance with virtue, the obvious next question is: what are the virtues, and how do we get them? Aristotle splits them in two. Intellectual virtues — wisdom, understanding, prudence — come largely through teaching. Moral virtues — courage, generosity, justice, temperance — come through habituation. We are not born just any more than we are born able to play the lyre. We become just by doing just acts, brave by doing brave acts, temperate by being temperate again and again, until the disposition is built into us and the corresponding action becomes second nature.

Moral virtue comes about as a result of habit… we become just by doing just acts, temperate by doing temperate acts, brave by doing brave acts.

Each moral virtue sits between two vices — one of deficiency, one of excess. Courage is the mean between cowardice and rashness. Generosity is the mean between stinginess and wastefulness. Friendliness between sullenness and obsequiousness. The mean is not a mathematical average; it is relative to the person and the situation. The right amount of fear for a soldier facing a charge is not the right amount of fear for a child facing a dog. Knowing where the mean lies, in this case, now, takes judgement that no rulebook can supply.

Phronesis — practical wisdom

This is where the system would collapse without one further idea. If finding the mean is contextual, there must be some faculty that does the finding. Aristotle names it phronesis, usually translated as practical wisdom. Phronesis is the intellectual virtue that lets us deliberate well about what to do in particular cases — not what is good in general, but what to do here, with this person, under these constraints, given who I am.

It is sharply distinguished from sophia, theoretical wisdom about eternal truths. A prodigy can do great mathematics at sixteen, because mathematics deals with what cannot be otherwise. But a sixteen-year-old cannot be phronetic, because practical wisdom is built out of experience — of having tried things, seen them fail, watched people, lived through consequences. It accrues. It cannot be downloaded.

The consequence is striking. Ethics, for Aristotle, resists algorithms. You cannot write down a procedure that, fed any situation, returns the right action. The right action depends on perception — on seeing what is salient about this situation — and perception of the morally relevant features depends on already being a certain kind of person. Character and judgement are tangled: only the courageous person reliably sees what is courageous to do; only the just person reliably sees what is just. This is why moral education matters so much, and so early.

Friendship and the contemplative life

Books VIII and IX of the Ethics are devoted to friendship — an astonishing fraction of the work. Aristotle distinguishes three kinds. Friendships of utility, in which we are useful to one another (the colleague, the trading partner). Friendships of pleasure, in which we enjoy one another's company (the drinking companion). And friendships of virtue, in which we love the other for who they are, for their excellence of character. Only the last is stable, because the first two dissolve the moment the use or pleasure does.

Friendship of virtue is necessary, not optional, for the good life. We need others to flourish — not as instruments, but as mirrors and companions in excellence. A self-sufficient man, Aristotle says, would be miserable; no one would choose to live without friends, even if they had every other good.

The final book turns to the highest activity. Reason is what makes us most human; contemplation — the free use of reason on the highest objects — is reason at its freest. The contemplative life, Aristotle concludes, is the most god-like activity available to us, and so the most complete eudaimonia. Some interpreters think this leaves the work with two ideals in tension: the active, virtuous, political life of the citizen, and the philosopher's contemplative withdrawal. Aristotle does not quite resolve the tension. He may not have meant to.

What remains, two and a half millennia on, is the shape of the project. Ask what a human life is for. Answer it not with a rule but with a character. Build the character through repetition. Refine the judgement through experience. Find people who deserve your love. Make time for thought. It is not a flashy program. It is, by long-running consensus of those who have tried it, a true one.