Whatever you do in life, if you want to be creative and intelligent, and develop your brain, you must do everything with the awareness that everything, in some way, connects to everything else.

Whoever in debate quotes authority uses not intellect, but memory.

The motive power is the cause of all life.

Painting is poetry that is seen rather than felt, and poetry is painting that is felt rather than seen.

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.

The variety of colour in objects cannot be discerned at a great distance, excepting in those parts which are directly lighted up by the solar rays.

If a man has a tent made of linen of which the apertures have all been stopped up, and be it twelve bracchia across (over twenty-five feet) and twelve in depth, he will be able to throw himself down from any height without sustaining injury. [His concept of the parachute.]