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.
Hence poetry is something more philosophic and of graver import than history, since its statements are of the nature rather of universals, whereas those of history are singulars.
It is well said, then, that it is by doing just acts that the just man is produced, and by doing temperate acts the temperate man; without doing these no one would have even a prospect of becoming good. But most people do not do these, but take refuge in theory and think they are being philosophers and will become good in this way, behaving somewhat like patients who listen attentively to their doctors, but do none of the things they are ordered to do.
But if nothing but soul, or in soul mind, is qualified to count, it is impossible for there to be time unless there is soul, but only that of which time is an attribute, i.e. if change can exist without soul.
Even when laws have been written down, they ought not always to remain unaltered. As in other sciences, so in politics, it is impossible that all things should be precisely set down in writing; for enactments must be universal, but actions are concerned with particulars. Hence we infer that sometimes and in certain cases laws may be changed.
If purpose, then, is inherent in art, so is it in Nature also. The best illustration is the case of a man being his own physician, for Nature is like that - agent and patient at once.
All are agreed that the various moral qualities are in a sense bestowed by nature: we are just, and capable of temperance, and brave, and possessed of the other virtues from the moment of our birth. But nevertheless we expect to find that true goodness is something different, and that the virtues in the true sense come to belong to us in another way. For even children and wild animals possess the natural dispositions, yet without Intelligence these may manifestly be harmful.
The good of man is the active exercise of his soul's faculties. This exercise must occupy a complete lifetime. One swallow does make a spring, nor does one fine day. Excellence is a habit, not an event.