But our definition itself clears up the difficulty; 16 for happiness was defined as a certain kind of exercise of the vital faculties in accordance with excellence or virtue. And of the remaining goods [other than happiness itself], some must be present as necessary conditions, while others are aids and useful instruments to happiness. And this agrees with what we said at starting. We then laid down that the end of the art political is the best of all ends; but the chief business of that art is to make the citizens of a certain character⁠—that is, good and apt to do what is noble. It is not without reason, then, that we do not call an ox, or a horse, or any brute happy; for none of them is able to share in this kind of activity.