Experiment is the sole interpreter of the artifices of Nature.

Experience, the interpreter between creative nature and the human race, teaches the action of nature among mortals: how under the constraint of necessity she cannot act otherwise than as reason, who steers her helm, teaches her to act.

First study the science, and then practice the art which is born of that science.

The motions of men must be such as suggest their dignity or their baseness.

You should look at certain walls stained with damp, or at stones of uneven color. If you have to invent some backgrounds you will be able to see in these the likeness of divine landscapes, adorned with mountains, ruins, rocks, woods, great plains, hills and valleys in great variety; and expressions of faces and clothes and an infinity of things which you will be able to reduce to their complete and proper forms. In such walls the same thing happens as in the sound of bells, in whose stroke you may find every named word which you can imagine.

Truth was the only daughter of Time.

Affective gestures pointing to things near either in time or space should be made with the hand not very far from the body of the person pointing; and if these things are distant, the hand of the painter should be more extended and the face turned toward the person to whom he is addressing the demonstration.