Nicomachean Ethics

Aristotle's central claim is that eudaimonia—happiness—is activity of the soul in accordance with virtue, not a feeling, a gift of fortune, or mere possession of a virtuous character. He rejects the view that happiness consists in honor, pleasure, or wealth, and he also rejects Socrates' intellectualist position that virtue is simply knowledge. For Aristotle, virtue requires both right reason and properly habituated desires; knowing what is good is insufficient if one's character has not been trained to take pleasure in acting well.

The function argument (ergon argument) in Book I.7 reasons that if humans have a characteristic activity, then the human good lies in performing that activity well. Since the distinctive human capacity is rational activity, the human good is rational activity exercised with virtue. This argument shifts ethics from a theoretical inquiry into abstract good into a practical science about how to live. It also explains why Aristotle treats ethics as inexact—its subject matter admits of variation, so its conclusions hold only 'for the most part,' not with mathematical precision.

Plato's dialogues, especially the Republic, treat ethics as continuous with metaphysics and often seek a single, transcendent Form of the Good that explains all value. Aristotle's Nicomachean Ethics proceeds inductively, starting from common opinions and the way virtuous people actually behave. He does not posit a separate Form of the Good but locates the good in the activity of living well. The method is practical and dialectical rather than deductive, and the emphasis falls on habituation, practical wisdom, and the particularity of moral situations.

The work's reception has fluctuated dramatically. In the early twentieth century, figures like G. E. Moore and H. A. Prichard dismissed Aristotelian virtue as a basis for morality, and Dewey called it 'remote and empty' . The 1958 publication of Elizabeth Anscombe's 'Modern Moral Philosophy' helped revive interest in virtue ethics, and by the 1980s Aristotle's text had become central to Anglo-American normative theory, influencing thinkers like Philippa Foot and Alasdair MacIntyre .

The Nicomachean Ethics is explicitly framed as a work of political science. Aristotle states at the outset that the inquiry belongs to politics, since the good of the city encompasses the good of individuals. The final book transitions to a discussion of legislation and constitutions, and the work's argument assumes that virtue is cultivated within a political community. For Aristotle, ethics and politics are continuous: the question of how an individual should live cannot be separated from the question of how the polis should be organized.