Nicomachean Ethics

For instance, both to feel fear and confidence and appetite and anger and pity and in general pleasure and pain is possible both more and less, and in both ways not well; but to do so when one ought, and in the cases one ought, and toward whom one ought, and for the sake of what one ought, and as one ought, is both the mean and the best, which is the mark of virtue. Similarly, also concerning actions there is excess, deficiency, and the mean. And virtue is concerned with passions and actions, in which excess is in error and deficiency is blamed, while the mean is praised and successful; and both of these are characteristic of virtue. Virtue, then, is a certain mean, being at any rate aiming at the mean. Further, to err is possible in many ways (for evil belongs to the unlimited, as the Pythagoreans conjectured, and good to the limited), but to succeed is possible in only one way (wherefore also the one is easy and the other difficult—easy to miss the mark, difficult to hit it); and for these reasons, then, excess and deficiency belong to vice, but the mean to virtue; ”For men are good in but one way, but bad in all sorts of ways.” Virtue, then, is a state of character concerned with choice, lying in a mean, i.e. the mean relative to us, this being determined by a rational principle, and by that principle by which the man of practical wisdom would determine it. And it is a mean between two vices, that which depends on excess and that which depends on deficiency; and again, by the fact that the vices either fall short of or exceed what is right in both passions and actions, while virtue both finds and chooses that which is intermediate. Wherefore, according to its substance and the definition which states its essence, virtue is a mean, but with regard to what is best and right, an extreme. But not every action nor every passion admits of a mean; for some have names that already imply badness, for instance, spite, shamelessness, envy, and in the case of actions, adultery, theft, murder; for all these and suchlike things are so called because they themselves are bad, and not because of their excesses or deficiencies. It is not possible, then, ever to be right with regard to them, but one must always be in error; nor does goodness or badness with regard to such things depend on committing adultery with the right woman, at the right time, and in the right way, but simply to do any of them is to err. It is equally absurd, then, to expect that in unjust action, cowardice, and self-indulgence there should be a mean, an excess, and a deficiency; for then there would be a mean of excess and deficiency, an excess of excess, and a deficiency of deficiency. But just as there is no excess and deficiency of temperance and courage because what is intermediate is in a sense an extreme, so also of those actions there is no mean nor excess and deficiency, but however they are done they are wrong; for in general, there is neither a mean of excess and deficiency, nor an excess and deficiency of a mean.