Since the branch of philosophy on which we are at present engaged differs from the others in not being a subject of merely intellectual interest — I mean we are not concerned to know what goodness essentially is, but how we are to become good men, for this alone gives the study its practical value — we must apply our minds to the solution of the problems of conduct.
Humor is the only test of gravity, and gravity of humor; for a subject which will not bear raillery is suspicious, and a jest which will not bear serious examination is false wit.
Now, the causes being four, it is the business of the student of nature to know about them all, and if he refers his problems back to all of them, he will assign the "why" in the way proper to his science-the matter, the form, the mover, that for the sake of which.
Every man should be responsible to others, nor should any one be allowed to do just as he pleases; for where absolute freedom is allowed, there is nothing to restrain the evil which is inherent in every man.
Tyrants preserve themselves by sowing fear and mistrust among the citizens by means of spies, by distracting them with foreign wars, by eliminating men of spirit who might lead a revolution, by humbling the people, and making them incapable of decisive action.
There is also a doubt as to what is to be the supreme power in the state: - Is it the multitude? Or the wealthy? Or the good? Or the one best man? Or a tyrant?