The mind commands the body, and it obeys forthwith; the mind commands itself, and is resisted. The mind commands the hand to be moved, and such readiness is there that the command is scarce to be distinguished from the obedience. Yet the mind is mind, and the hand is body. The mind commands the mind to will, and yet, though it be itself, it obeyeth not. Whence this monstrous thing? and why is it?
"The Confessions of St. Augustine".