The eye transmits its own image through the air to all the objects which face it, and also receives them on its own surface, whence the "sensus communis" takes them and considers them.

The Medici created and destroyed me.

In the days of thy youth seek to obtain that which shall compensate the losses of thy old age.

No human investigation can claim to be scientific if it doesn't pass the test of mathematical proof.

A painter should begin every canvas with a wash of black, because all things in nature are dark except where exposed by the light.

Never make heads straight on the shoulders, but turn them aside to the right or to the left, even though they look down, or upward, or straight ahead, because it is necessary for them to look lively and awake and not asleep. And do not depict the front or rear half of the whole person so that too much straightness is displaced, one half above or below the other half; and if you should wish to use stiff figures, do so only in portraying old people.

Fire is to represent truth because it destroys all sophistry and lies; and the mask is for lying and falsehood which conceal truth.