I say that the power of vision extends through the visual rays to the surface of non-transparent bodies, while the power possessed by these bodies extends to the power of vision.

One's thoughts turn towards Hope.

The limiting surface of one thing is the beginning of another.

The painter who draws merely by practice and by eye, without any reason, is like a mirror which copies every thing placed in front of it without being conscious of their existence.

All our knowledge originates in opinion.

Just as a well-filled day brings blessed sleep, so a well-employed life brings a blessed death.

Drawing is based upon perspective, which is nothing else than a thorough knowledge of the function of the eye.