Summary of "Nicomachean Ethics"

Core Idea

Happiness is virtue in action, not thought or pleasure alone—it requires building excellent character through repeated practice, then exercising it in community
You are responsible for your character because you build it daily through choices; you cannot blame circumstances or claim ignorance of what you've trained yourself to ignore
Virtue is the mean between extremes—courage between cowardice and recklessness; moderation in all things is the path to excellence

Virtue is a habit, not innate talent or abstract knowledge—you develop it by doing virtuous acts repeatedly until they become second nature
Right action requires three elements: correct knowledge of the specific situation (not just general rules), deliberate choice made for its own sake, and a stable virtuous character
Moral virtue and practical wisdom are inseparable—you need both the habit of excellence AND the judgment to apply it wisely to real circumstances
Weakness of will differs from vice: the incontinent person knows what's right but fails to act on it (recoverable); the vicious person doesn't truly grasp it as good (entrenched)

Cultivate few deep friendships, not many—genuine friendship requires shared life and activity with people of similar virtue who wish each other's good for its own sake
Give more than you receive in friendship—the giver benefits more; focus on actively loving rather than being loved
Unequal friendships (mentor-student, parent-child) require proportional effort, not equality
Pleasure reinforces virtue when it follows noble action—distinguish between corrupting bodily excess and legitimate moderate pleasure that completes good activity

Contemplation (intellectual activity) yields the deepest happiness, exceeding even practical virtue—the examined life and philosophical study are the highest goods
You need only moderate external goods—health, basic resources, and social connection suffice; wealth and luxury don't increase happiness
Embed virtue through law and custom, not willpower alone—build systems and community that reinforce good habits
Start young, maintain always—one-time training fails; lifelong practice and social structure keep virtue alive

Choose one virtue to practice daily (courage, generosity, moderation)—repeat the act deliberately until it feels natural, adjusting for context
Identify your character in what you enjoy—notice what pleasures attract you; corrupt pleasures reveal a corrupting character; pivot toward nobler activities
Invest in 1-2 deep friendships where you share life and mutual virtue; reduce time with utility/pleasure-based relationships
Join or create a community of practice—laws, groups, or habits that reinforce virtue; don't rely on isolated willpower
Reserve time for thinking and learning—contemplation is the highest happiness; make intellectual growth a non-negotiable habit