Nicomachean Ethics

This text is a philosophical treatise on ethics, exploring the nature of the good life and human happiness. It argues that the ultimate end for human beings is happiness (eudaimonia), which is not a state of being but an activity of the soul in accordance with the highest virtue. The work systematically examines the nature of moral and intellectual virtues, the role of pleasure and friendship in a good life, and concludes by identifying the life of contemplation as the highest and most complete form of happiness.

The Nature of Happiness and Virtue (Book I) The book begins by establishing that all human actions aim at some good, and the highest good, which is desired for its own sake, is happiness. Happiness is defined not as pleasure, honor, or wealth, but as "an activity of the soul in accordance with virtue." The author posits that to understand happiness, one must understand the function of a human being, which is the exercise of reason. Therefore, the good life for a person consists in performing rational activities well, which is to say, virtuously. This requires a complete life, as "one swallow does not make a spring." The soul is divided into a rational part and an irrational part, which gives rise to two kinds of virtues: intellectual and moral.

The Doctrine of Moral Virtue (Books II-V) This section elaborates on the nature of moral virtue. Unlike intellectual virtues, which are taught, moral virtues are acquired through habit and practice; one becomes just by doing just acts. Moral virtue is defined as a disposition to choose the "mean" between two extremes of excess and deficiency. For example, courage is the mean between cowardice and recklessness. This mean is relative to the individual and determined by right reason or prudence. The text then provides a detailed analysis of specific moral virtues, including courage, temperance (moderation in bodily pleasures), liberality (right conduct regarding wealth), and high-mindedness (proper pride). A significant portion is dedicated to justice, which is unique in that it is a virtue in relation to others. The author distinguishes between distributive justice (fair distribution of honors or goods) and corrective justice (remedying wrongs in private transactions). The concepts of voluntary and involuntary action, choice, and deliberation are analyzed as prerequisites for virtuous or vicious conduct.

Intellectual Virtues and States of Character (Books VI-VII) This part shifts focus to the intellectual virtues, which pertain to the rational part of the soul. The rational part is itself divided into the scientific faculty (which contemplates invariable truths) and the calculative faculty (which deals with variable things). The primary intellectual virtues are Wisdom (sophia), which is knowledge of the highest and most universal principles, and Prudence or Practical Wisdom (phronesis), which is the ability to deliberate well about what is good and expedient for life as a whole. Prudence is essential for moral virtue, as it is the faculty that identifies the correct mean in any given situation. This section also examines states of character that are neither pure virtue nor vice, such as continence (acting rightly despite having bad desires) and incontinence (knowing what is right but failing to act on it due to passion). The incontinent person is distinguished from the profligate or vicious person, as the latter chooses evil deliberately, while the former acts against their better judgment and is therefore more curable.

Friendship, Pleasure, and the Contemplative Life (Books VIII-X) The final section explores the crucial roles of friendship and pleasure in a happy life. Three types of friendship are identified, based on their motives: utility, pleasure, and goodness. Friendships of utility and pleasure are accidental and tend to be short-lived, dissolving when the utility or pleasure ceases. The perfect and most lasting friendship is that between good men who love each other for their character and virtue. This kind of friendship is essential for a happy life, as a friend is a "second self" with whom one can share a common life and contemplate virtuous actions. The book then re-examines pleasure, refuting the ideas that it is inherently bad or merely a process of replenishment. It concludes that pleasure is the natural completion of an unimpeded activity. The highest and purest pleasures accompany the highest activities. This leads to the final conclusion of the entire work: since reason is the highest faculty in man, the most perfect happiness consists in the exercise of this faculty—the life of contemplation. This life is the most self-sufficient, leisurely, and akin to the divine, and therefore constitutes the highest form of human flourishing.