We must doubt the certainty of everything which passes through the senses, but how much more ought we to doubt things contrary to the senses, such as the existence of God and the soul.
Leonardo da VinciO painter skilled in anatomy, beware lest the undue prominence of the bones, sinews and muscles cause you to become a wooden painter from the desire to make your nude figures reveal all.
Leonardo da VinciSupreme happiness will be the greatest cause of misery, and the perfection of wisdom the occassion of folly.
Leonardo da VinciWhen the sun is covered by clouds, objects are less conspicuous, because there is little difference between the light and shade of the trees and the buildings being illuminated by the brightness of the atmosphere which surrounds the objects in such a way that the shadows are few, and these few fade away so that their outline is lost in haze.
Leonardo da VinciAlthough 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.
Leonardo da Vinci