The painter will produce pictures of little merit if he takes the works of others as his standard.

Where the spirit does not work with the hand, there is no art.

Men of genius sometimes accomplish most when they work least, for they are thinking out inventions.

He who does not understand the supreme certainty of mathematics is wallowing in confusion.

The painter's mind is a copy of the divine mind, since it operates freely in creating the many kinds of animals, plants, fruits, landscapes, countrysides, ruins, and awe-inspiring places.

Test knowledge through experience, be prepared to make mistakes, and be persistent about it.

All our knowledge is the offspring of our perceptions.