Thus it is thought that justice is equality; and so it is, but not for all persons, only for those that are equal. Inequality also is thought to be just; and so it is, but not for all, only for the unequal. We make bad mistakes if we neglect this for whom when we are deciding what is just. The reason is that we are making judgements about ourselves, and people are generally bad judges where their own interests are involved.
A state is an association of similar persons whose aim is the best life possible. What is best is happiness, and to be happy is an active exercise of virtue and a complete employment of it.
Jealousy is both reasonable and belongs to reasonable men, while envy is base and belongs to the base, for the one makes himself get good things by jealousy, while the other does not allow his neighbour to have them through envy.
Moral virtue is ... a mean between two vices, that of excess and that of defect, and ... it is no small task to hit the mean in each case, as it is not, for example, any chance comer, but only the geometer, who can find the center of a given circle.