Error is multiform (for evil is a form of the unlimited, as in the old Pythagorean imagery, and good of the limited), whereas success is possible in one way only (which is why it is easy to fail and difficult to succeed - easy to miss the target and difficult to hit it); so this is another reason why excess and deficiency are a mark of vice, and observance of the mean a mark of virtue: Goodness is simple, badness is manifold.
AristotleBetween friends there is no need for justice, but people who are just still need the quality of friendship; and indeed friendliness is considered to be justice in the fullest sense.
AristotleExcellence or virtue is a settled disposition of the mind that determines our choice of actions and emotions and consists essentially in observing the mean relative to us ... a mean between two vices, that which depends on excess and that which depends on defect.
AristotleFor we do not think that we know a thing until we are acquainted with its primary conditions or first principles, and have carried our analysis as far as its simplest elements.
AristotleInasmuch as every family is a part of a state, and these relationships are the parts of a family, and the virtue of the part must have regard to the virtue of the whole, women and children must be trained by education with an eye to the constitution, if the virtues of either of them are supposed to make any difference in the virtues of the state. And they must make a difference: for the children grow up to be citizens, and half the free persons in a state are women.
Aristotle