Again, it is possible to fail in many ways (for evil belongs to the class of the unlimited and good to that of the limited), while to succeed is possible only in one way (for which reason also one is easy and the other difficultโto miss the mark easy, to hit it difficult); for these reasons also, then, excess and defect are characteristic of vice, and the mean of virtue; For men are good in but one way, but bad in many.
AristotleIf what was said in the Ethics is true, that the happy life is the life according to virtue lived without impediment, and that virtue is a mean, then the life which is in a mean, and in a mean attainable by every one, must be the best. And the same principles of virtue and vice are characteristic of cities and of constitutions; for the constitution is in a figure the life of the city.
Aristotle