...we are all inclined to ... direct our inquiry not by the matter itself, but by the views of our opponents; and, even when interrogating oneself, one pushes the inquiry only to the point at which one can no longer offer any opposition. Hence a good inquirer will be one who is ready in bringing forward the objections proper to the genus, and that he will be when he has gained an understanding of the differences.
Men are divided between those who are as thrifty as if they would live forever, and those who are as extravagant as if they were going to die the next day.
There are, then, three states of mind ... two vices--that of excess, and that of defect; and one virtue--the mean; and all these are in a certain sense opposed to one another; for the extremes are not only opposed to the mean, but also to one another; and the mean is opposed to the extremes.
Soul and body, I suggest react sympathetically upon each other. A change in the state of the soul produces a change in the shape of the body and conversely, a change in the shape of the body produces a change in the state of the soul.
If the state cannot be entirely composed of good men, and yet each citizen is expected to do his own business well, and must therefore have virtue, still inasmuch as all the citizens cannot be alike, the virtue of the citizen and of the good man cannot coincide. All must have the virtue of the good citizen - thus, and thus only, can the state be perfect; but they will not have the virtue of a good man, unless we assume that in the good state all the citizens must be good.