Εὐδαιμονία

['Happiness'] and 'happy'. Some of the contraries do not have intermediates; for example, for man illness or health, white and black;¹ but happy and unhappy do have intermediates. For if someone is happy, he is not unhappy; but if he is not happy, he is not necessarily unhappy. For happiness and unhappiness are not opposed without intermediate, since it is possible that someone, even being an excellent person, is not happy. And if he is excellent, he is necessarily not bad. For virtue and vice are not without intermediate. And the temperate person is not mad; but it is not the case that whoever is not temperate is mad.² Consequently, the things that are contraries in this sense are no longer useful for constructive reasoning and refutation.
But by interpreting the word according to its etymology we say that the excellent man is happy, and we interpret "the happy person" according to its etymology; for the name eudaimon seems to signify the one who has a good [eu] daimon/genius. In fact, if the soul of everyone is a daimon, as Xenocrates thinks,³ the person having a good soul would be happy. But the excellent man has a good soul. Therefore, the happy person is an excellent man.⁴