We know more about the movement of celestial bodies than about the soil underfoot.

To speak of this subject you must... explain the nature of the resistance of the air, in the second the anatomy of the bird and its wings, in the third the method of working the wings in their various movements, in the fourth the power of the wings and the tail when the wings are not being moved and when the wind is favourable to serve as guide in various movements.

Patience serves as a protection against wrongs as clothes do against cold. For if you put on more clothes as the cold increases, it will have no power to hurt you. So in like manner you must grow in patience when you meet with great wrongs, and they will then be powerless to vex your mind.

Perspective is the rein and rudder of painting.

Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.

To be a winner you must want to win but must know of the chance of losing and must not fear of it.

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.