Necessity is a guardian in Nature.

The wisest and noblest teacher is nature itself.

Experience does not err. Only your judgments err by expecting from her what is not in her power.

The eye is the window of the human body through which it feels its way and enjoys the beauty of the world.

A deaf and dumb person who sees two men in conversation - may nevertheless understand from the attitudes and gestures of the speakers, how well their discussion is getting along.

After painting comes Sculpture, a very noble art, but one that does not in the execution require the same supreme ingenuity as the art of painting, since in two most important and difficult particulars, in foreshortening and in light and shade, for which the painter has to invent a process, sculpture is helped by nature. Moreover, Sculpture does not imitate color which the painter takes pains to attune so that the shadows accompany the lights.

He who is fixed to a star does not change his mind.