Aristotle, Nicomachean Ethics
H. Rackham, Ed.

by actually comporting themselves in one way or the other in relation to those passions. In a word, our moral dispositions are formed as a result of the corresponding activities. 1. [8] Hence it is incumbent on us to control the character of our activities, since on the quality of these depends the quality of our dispositions. It is therefore not of small moment whether we are trained from childhood in one set of habits or another; on the contrary it is of very great, or rather of supreme, importance.2.

As then our present study, unlike the other branches of philosophy, has a practical aim （for we are not investigating the nature of virtue for the sake of knowing what it is, but in order that we may become good, without which result our investigation would be of no use）, we have consequently to carry our enquiry into the region of conduct, and to ask how we are to act rightly; since our actions, as we have said, determine the quality of our dispositions.2. [2]

Now the formula ‘to act in conformity with right principle’ is common ground, and may be assumed as the basis of our discussion. （We shall speak about this formula later,¹ and consider both the definition of right principle and its relation to the other virtues.）