Will is the measure of power. To a great genius there must be a great will. If the thought is not a lamp to the will, does not proceed to an act, the wise are imbecile. He alone is strong and happy who has a will. The rest are herds. He uses; they are used. He is of the Maker; they are of the Made. Will is always miraculous, being the presence of God to men. When it appears in a man he is a hero, and all metaphysics are at fault.

The Works of Ralph Waldo Emerson: Natural history of intellect (ed. 1893)