Man is a goal-seeking animal. His life only has meaning if he is reaching out and striving for his goals.

The more you know, the more you know you don't know.

When their adventures do not succeed, however, they run away; but it was the mark of a brave man to face things that are, and seem, terrible for a man, because it is noble to do so and disgraceful not to do so.

All men by nature desire knowledge.

Poetry demands a man with a special gift for it, or else one with a touch of madness in him.

A man who examines each subject from a philosophical standpoint cannot neglect them: he has to omit nothing, and state the truth about each topic.

To be always seeking after the useful does not become free and exalted souls.