The finished man, you know, is difficult to please; a growing mind will ever show you gratitude. --Faust 1, lines 182-3

A man doesn't learn to understand anything unless he loves it.

Art is long, life is short; judgement difficult, opportunity transient.

One must not criticize that which is common since it remains always the same.

If you start to think of your physical and moral condition, you usually find that you are sick.

Every man has enough power left to carry out that of which he is convinced.

He who cannot draw on three thousand years is living from hand to mouth.