Happiness consists in a complete life lived according to virtue. It is difficult to say whether the happiness of a person after death should depend on the fortunes of his descendants. Another difficulty is that a noble person may suffer external misfortunes which lessen his happiness. However, a virtuous person will endure misfortunes much better than an ignoble one. Therefore regardless of external circumstances no happy person will ever wretched, because to be wretched one must do something hateful or bad.
Happiness is the principle of actions and the cause of all good things.
It is thus worthy of honor. Because happiness is an activity of the soul according to virtue, it is necessary to examine human virtue. These two senses are the origin of the distinction between intellectual and ethical virtues, respectively. Aristotle begins his study on ethics by asserting that there is some ultimate good which is both complete and self-sufficient, and defines this good as happiness. There must be one final end of all human actions, because a human action by definition is one that is done on purpose and for a definite goal.