Let us review the argument to this point. In book 1 Aristotle argues that the ultimate goal of human life is some “activity in accordance with virtue,” and he sets down criteria that he thinks the ultimate goal must satisfy. In 1.13 and 2.1 he analyzes human virtue into thinking-related and character-related virtue, and in the remainder of book 2 he constructs a list, which he regards as exhaustive, of particular character-related virtues. One would think that his next step would be to examine these virtues individually. In fact he puts this off until 3.6. Instead, in 3.1–5 he undertakes a discussion of human action and the psychology underlying human action.

This is not a digression, as it might seem, because Aristotle's discussion of human action follows naturally from, and is even required by, various claims that he had put forward in book 2. Recall that, as Aristotle sees it, the discipline of ethics is practical: its aim is that we become good and live well. But, as he has just argued in book 2, we cannot become good unless we acquire the virtues of character. As we saw, Aristotle thinks that we generally acquire the virtues through being directed, by those in authority over us (by our parents when we are immature, and by legislators, even when we are mature citizens), to do actions characteristic of those virtues and to refrain from actions characteristic of the contrary vices.