eudaimonia

Eudaimonia is a central concept in ancient Greek philosophy, commonly translated as happiness or flourishing. Etymologically, it derives from eu ("good") and daimon ("spirit" or guiding power), suggesting "having a good spirit" or blessedness. In Aristotle's Nicomachean Ethics, it is the highest good toward which all human actions aim: a complete, self-sufficient life that ends in itself rather than as a means to another end.

Aristotle argues that eudaimonia results from rational activity in accordance with virtue. The human function is the rational part of the soul; by exercising virtuous habits—moral virtues such as courage, temperance, justice, and intellectual virtues such as practical wisdom—we perform this function well across a full life. Virtue lies in finding the mean between extremes and requires habituation. External goods such as wealth or health are relevant but not sufficient to secure eudaimonia.

After Aristotle, eudaimonia remained influential in Hellenistic philosophy; the Stoics described it as living in accord with nature and virtue. In modern times it survives in virtue ethics as flourishing or well-being and influences positive psychology's study of optimal functioning. Debates persist over whether eudaimonia is a state or an activity, how much external goods matter, and whether a complete life is a realistic criterion.