And they deny that any man has ever been seen who does not know what it is to be angry; and they name what we call lenity by the bad appellation of indolence.

Nor do they commend only this lust (for anger is, as I defined it above, the lust of revenge), but they maintain that kind of lust or desire to be given us by nature for very good purposes, saying that no one can execute anything well but what he is in earnest about.

Themistocles used to walk in the public places in the night because he could not sleep; and when asked the reason, his answer was, that Miltiades's trophies kept him awake.

Who has not heard how Demosthenes used to watch, who said that it gave him pain if any mechanic was up in a morning at his work before him?
Lastly, they urge that some of the greatest philosophers would never have made that progress in their studies without some ardent desire spurring them on .-- We are informed that Pythagoras, Democritus, and Plato visited the remotest parts of the world; for they thought that they ought to go wherever anything was to be learned.

Now, it is not conceivable that these things could be effected by anything but by the greatest ardor of mind.
XX.