For A. each human being has an ultimate end, a thing that is good for its own sake. This is happiness or eudaimonia. That depends on the sort of things humans are. We are rational beings and so the good life for human beings must be a good life for rational beings. The function of man then is activity of soul in accordance with reaon.
Happiness is the virtuous actvity of the soul.
Virtue and habit, p. 326. Nothing naturally good. Training oneslf to do good, attuning pleasures and pains. Extreme of excess versus extreme of definiciency.