Aristotle suggests three practical rules of conduct: first, avoid the extreme that is farther from the mean; second, notice what errors we are particularly susceptible to and avoid them diligently; and third, be wary of pleasure, as it often impedes our judgment.
“Virtue” is the most common translation of the Greek word arete, though it is occasionally translated as “excellence.” Virtue is usually an adequate translation in the Ethics because it deals specifically with human excellence, but arete could be used to describe any kind of excellence, such as the sharpness of a knife or the fitness of an athlete. Just as a knife’s excellence rests in its sharpness, a person’s excellence rests in living according to the various moral and intellectual virtues.
Aristotle describes virtue as a disposition, distinguishing it not only from feelings and faculties, but also (less explicitly) from activities. Aristotle calls happiness an activity, or energeia, in Book I, meaning that happiness is not an emotional state but a way of life. Happiness is exhibited not in how we are but in how we act. Virtue, by contrast, is a disposition, or hexis, meaning that it is a state of being and not an activity. More precisely, virtue is the disposition to act in such a way as to lead a happy life.
Without virtue, we cannot be happy, though possessing virtue does not in itself guarantee happiness. In Book I, Chapter 8, Aristotle points out that those who win honors at the Olympic Games are not necessarily the strongest people present but rather the strongest people who actually compete. Perhaps one of the spectators is strong-er than all of the competitors, but this spectator has no right to win honors. Similarly, a person might have a virtuous disposition but will not lead a happy life unless he or she acts according to this disposition.
It may seem odd to us that Aristotle at no point argues for what dispositions should be considered virtuous and which vicious. The need for justification seems even more pressing in the modern world, where our views on virtue and vice may not entirely agree with Aristotle’s.
However, it is not Aristotle’s intention to convince us of what is virtuous, and he differs from most modern moral philosophers in placing very little emphasis on rational argument in moral development. Instead, as he argues at the beginning of Book II, learning virtue is a matter of habit and proper training. We do not become courageous by learning why courage is preferable to cowardice or rashness, but rather by being trained to be courageous. Only when we have learned to be instinctively courageous can we rightly arrive at any reasoned approval of courage. Recalling that arete may refer to any form of excellence, we might draw an analogy between learning courage and learning rock-climbing. We learn to become good rock-climbers through constant practice, not through reasoned arguments, and only when we have become good rock-climbers and appreciate firsthand the joys of rock-climbing can we properly understand why rock-climbing is a worthwhile activity.