Hence we ought to make sure that our acts be of a certain kind; for the resulting character varies as they vary. It makes no small difference, therefore, whether a man be trained from his youth up in this way or in that, but a great difference, or rather all the difference.

But our present inquiry has not, like the rest, a merely speculative aim; we are not inquiring merely in order to know what excellence or virtue is, but in order to become good; for otherwise it would profit us nothing. We must ask therefore about these acts, and see of what kind they are to be; for, as we said, it is they that determine our habits or character.

First of all, then, that they must be in accordance with right reason is a common characteristic of them, which we shall here take for granted, reserving for future discussion 21 the question what this right reason is, and how it is related to the other excellences.