Nature is full of infinite causes that have never occurred in experience.

I abhor the supreme folly of those who blame the disciples of nature in defiance of those masters who were themselves her pupils

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.

No human investigation can be called real science if it cannot be demonstrated mathematically.

There are three classes of people: those who see, those who see when they are shown, those who do not see.

Study without desire spoils the memory, and it retains nothing that it takes in.

The first object of the painter is to make a flat plane appear as a body in relief and projecting from that plane