It is possible to fail in many ways . . . while to succeed is possible only in one way (for which reason also one is easy and the other difficult - to miss the mark easy, to hit it difficult).

Happiness does not lie in amusement; it would be strange if one were to take trouble and suffer hardship all one's life in order to amuse oneself.

Our youth should also be educated with music and physical education.

If every tool, when ordered, or even of its own accord, could do the work that befits it... then there would be no need either of apprentices for the master workers or of slaves for the lords.

Thinking is different from perceiving and is held to be in part imagination, in part judgment

Truth is a remarkable thing. We cannot miss knowing some of it. But we cannot know it entirely.

What we know is not capable of being otherwise; of things capable of being otherwise we do not know, when they have passed outsideour observation, whether they exist or not. Therefore the object of knowledge is of necessity. Therefore it is eternal; for things that are of necessity in the unqualified sense are all eternal; and things that are eternal are ungenerated and imperishable.