Although human ingenuity may devise various inventions which, by the help of various instruments, answer to one and the same purpose, yet will it never discover any inventions more beautiful, more simple or more practical than those of nature, because in her inventions there is nothing lacking and nothing superfluous; and she makes use of no counterpoise when she constructs the limbs of animals in such a way as to correspond to the motion of their bodies, but she puts into them the soul of the body.

Study me, reader, if you delight in me, because on very few occasions shall I return to the world, and because the patience for this profession is found in very few, and only in those who wish to compose things anew. Come, oh men, to see the miracles that such studies will disclose to nature.

Everything proceeds from everything else and everything becomes everything, and everything can be turned into everything else.

The light and heat of the universe comes from the sun, and its cold and darkness from the withdrawal of the sun.

Let proportion be found not only in numbers and measures, but also in sounds, weights, times, and positions, and what ever force there is.

A good painter is to paint two main things, men and the working of man's mind.

When you are alone you are all your own.