Nicomachean Ethics

Aristotle's Nicomachean Ethics is ten books of lecture notes — probably compiled by his students at the Lyceum — that constitute the most systematic ancient attempt to answer the question: how should a human being live? The answer Aristotle gives is both more practical and more demanding than anything his contemporaries or his teacher Plato offered.

The book's central concept is eudaimonia — usually translated as "happiness" but better understood as "flourishing" or "living well." Aristotle's argument is that eudaimonia is not a feeling but an activity: it is what happens when you exercise your distinctively human capacities (reason, virtue) excellently over a complete lifetime. You cannot be happy in a moment; you can only be happy across a life. And you cannot be happy alone — the Ethics insists throughout that humans are political animals, designed for community, and that friendship (philia) is among the highest goods.

The book's moral psychology — the account of how virtues work — remains the most useful practical framework for thinking about character that Western philosophy has produced. Virtues are habituated dispositions: not innate but cultivated through repeated action. You become courageous by doing courageous things; you become just by doing just things; you become the kind of person who finds it natural to act well. The opposite is also true, which is why the Ethics treats moral education as urgent.

Aristotle opens by noting that every action and inquiry aims at some good, and asks what the highest good is — the thing we want for its own sake, not for the sake of something else. His answer is eudaimonia. Then he asks what eudaimonia consists of, and answers: the exercise of the soul's faculties in accordance with virtue (arete), over a complete lifetime, with adequate external goods (health, friendship, resources).

This generates the Ethics' main work: a systematic account of the virtues. Each virtue is a mean between two vices — courage is the mean between cowardice and recklessness; generosity is the mean between miserliness and profligacy. The mean is not a simple average; it is relative to the person and the situation, which is why practical wisdom (phronesis) — the capacity to perceive what virtue requires in particular circumstances — is the master virtue.

Books VIII and IX, on friendship, are the work's least expected but most lasting contribution. Aristotle distinguishes friendships of utility, pleasure, and virtue; only the last is friendship in the full sense, requiring sustained commitment to another person's good for their own sake. He argues that this kind of friendship is necessary for eudaimonia.

No. 1 · The doctrine of the mean. Virtue, Aristotle argues, is always a disposition to act, feel, and respond in ways that hit the mean relative to us — not too much, not too little. The power of this framework is that it treats moral failure as typically excess or deficiency, not simply wrong versus right. It is also a corrective to moralizing: the person who can't be courageous because they feel no fear is not admirable (Aristotle calls them insensible), any more than the person who feels too much fear.

No. 2 · The account of practical wisdom (Book VI). Phronesis — practical wisdom — is the capacity to deliberate well about what conduces to living well generally. Aristotle distinguishes it from scientific knowledge (which deals with necessary truths) and from technical skill (which produces a product). Practical wisdom has no product beyond the good life itself; it is the capacity to perceive what virtue requires in the messy particular situation in front of you. This account of moral reasoning — as perception rather than calculation — has been central to virtue ethics ever since.

No. 3 · Friendship (Books VIII–IX). The two books on friendship are unexpectedly rich. Aristotle argues that complete friendship — based on virtue rather than utility or pleasure — requires wishing the good of the other for their own sake, sustained over time, and mutual recognition. He argues that you cannot fully know yourself without a friend who knows you (a friend is "another self"). He also argues that friendship of this kind is rare, necessarily limited in number, and incompatible with enmity or contempt. The person with many "friends" of this kind probably has none.

Terence Irwin (Hackett, 1999) — the standard scholarly translation; precise, with extensive notes explaining terminology and philosophical context. Essential for serious readers.

David Ross / Lesley Brown (Oxford World's Classics, 2009) — the classic Ross translation revised by Brown; slightly more readable than Irwin, with a helpful introduction.

C.D.C. Reeve (Hackett, 2014) — another good scholarly translation; Reeve's philosophical commentary is useful.

For context: Alasdair MacIntyre's After Virtue (1981) is the essential modern book for understanding why Aristotle's ethics matter and why they largely disappeared from moral philosophy for centuries.

Nicomachean Ethics is for readers willing to engage with philosophy as a sustained technical project — Aristotle proceeds carefully, defines terms, qualifies claims, and builds on previous arguments. It rewards patience. Unlike Plato, Aristotle is not trying to dazzle you; he is trying to be right.

It is not for readers looking for inspiration or uplift. Aristotle's ethics are demanding without being comfortable. He notes frankly that eudaimonia requires external goods — adequate resources, good health, friends — and that the person born into poverty or disfigurement has worse prospects for flourishing. This is honest but not comforting.

Read Books I and X (the opening and closing arguments about happiness) first — they frame everything. Then Books II–IV (the virtues), VI (practical wisdom), and VIII–IX (friendship) are the core. Books V (justice) and VII (weakness of will) are important but can be returned to.

The terminology requires attention. "Happiness" (eudaimonia), "virtue" (arete), "reason" (logos), and "function" (ergon) each carry specific meanings that differ from their ordinary English uses. Irwin's translation provides glossaries; use them. The argument becomes much clearer once you have the technical vocabulary.

• Plato — The Republic. Aristotle was Plato's student and the Ethics is partly a systematic refutation of Plato's ethics and politics. Reading both makes the disagreements explicit.
• Alasdair MacIntyre — After Virtue (1981). The most important modern defense of Aristotelian ethics; argues that modern moral philosophy went wrong by abandoning the concept of virtue, and that only a return to Aristotle can recover it.
• Martha Nussbaum — The Fragility of Goodness (1986). A contemporary philosopher's engagement with Aristotle on luck, vulnerability, and what a good life requires.

1. Aristotle argues that eudaimonia requires external goods — resources, health, friends, good luck. Does this make his account of the good life honest or inadequate?
2. The doctrine of the mean sounds like moderation in everything. But Aristotle says there are actions (murder, adultery) where there is no mean — they are simply wrong. How does this qualify the doctrine?
3. Aristotle distinguishes practical wisdom from technical skill and from scientific knowledge. What does this distinction suggest about how we should think about moral expertise?
4. Books VIII–IX argue that complete friendship requires virtue, not just affection or usefulness. Most of our relationships are friendships of utility or pleasure. What does Aristotle think about this?
5. Aristotle says you become courageous by doing courageous things — virtue is habituated. But if you're not yet courageous, how do you do the first courageous thing?
6. The Nicomachean Ethics was probably lecture notes compiled by students. Does this change how you read it? What might Aristotle have said differently if he had written it himself?