Experience never misleads; what you are misled by is only your judgment, and this misleads you by anticipating results from experience of a kind that is not produced by your experiments.

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

The cat is nature's masterpiece.

When you are painting you should take a flat mirror and often look at your work within it, and it will then be seen in reverse, and will appear to be by the hand of some other master, and you will be better able to judge of its faults than in any other way.

There is no higher or lower knowledge, but one only, flowing out of experimentation.

I say that in narrative paintings one should mingle direct contraries close by, because they produce strong contrasts with one another, and all the more so when they are very close together; that is, the ugly next to the beautiful, the big to the small, the old to the young, the strong to the weak; in this way you will vary as much as possible and close by.

Those who condemn the supreme certainty of mathematics feed on confusion, and can never silence the contradictions of the sophistical sciences which lead to eternal quackery.