We are survival machines — robot vehicles blindly programmed to preserve the selfish molecules known as genes. – Richard Dawkins, The Selfish Gene

Man, when he is merely what he seems to be, is almost nothing. – Antonio Porchia, Voces, 1943, translated from Spanish by W.S. Merwin

Man is the only animal that laughs and weeps; for he is the only animal that is struck with the difference between what things are and what they ought to be. – William Hazlitt, The English Comic Writers, 1819