“Why does the eye see more clearly when asleep than the imagination when awake?”

“The eye sees a thing more clearly in dreams, than the imagination awake.”

“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.”

“While human ingenuity may devise various inventions to the same ends, it will never devise anything more beautiful, nor more simple, nor more to the purpose than nature does, because in her inventions nothing is lacking and nothing is superfluous.”

“Blinding ignorance does mislead us. O! Wretched mortals, open your eyes!”

“The organ of perception acts more readily than judgment.”

“Every now and then go away, have a little relaxation, for when you come back to your work your judgment will be surer. Go some distance away because then the work appears smaller and more of it can be taken in at a glance and a lack of harmony and proportion is more readily seen.”