"I have been impressed with the urgency of doing. Knowing is not enough; we must apply. Being willing is not enough; we must do."

"The mind of the painter is a copy of the divine mind, since it operates freely in creating countless forms of animals, plants, fruits, landscapes, countrysides, ruins, and other things."

"No human investigation can be called true science if it doesn't pass through mathematical demonstrations."

"Oh! how many are the times that I have been deceived!"

"Human subtlety will never devise an invention more beautiful, more simple or more direct than does nature, because in her inventions nothing is lacking and nothing is superfluous."