[the virtues] cannot exist without Prudence. A proof of this is that everyone, even at the present day, in defining Virtue, after saying what disposition it is [i.e. moral virtue] and specifying the things with which it is concerned, adds that it is a disposition determined by the right principle; and the right principle is the principle determined by Prudence.

It is this simplicity that makes the uneducated more effective than the educated when addressing popular audiences-makes them, as the poets tell us, 'charm the crowd's ears more finely.' Educated men lay down broad general principles; uneducated men argue from common knowledge and draw obvious conclusions.

The shape of the heaven is of necessity spherical; for that is the shape most appropriate to its substance and also by nature primary.

Of cases where a man is truthful both in speech and conduct when no considerations of honesty come in, from an habitual sincerity of disposition. Such sincerity may be esteemed a moral excellence; for the lover of truth, who is truthful even when nothing depends on it, will a fortiori be truthful when some interest is at stake, since having all along avoided falsehood for its own sake, he will assuredly avoid it when it is morally base; and this is a disposition that we praise.

Great men are always of a nature originally melancholy.

For it is owing to their wonder that men both now begin and at first began to philosophize... They were pursuing science in order to know, and not for any utilitarian end.

The only way to achieve true success is to express yourself completely in service to society.