[I]n a very imperfect state of the world’s arrangements … paradoxical as the assertion may be, the conscious ability to do without happiness gives the best prospect of realizing such happiness as is attainable. For nothing except that consciousness can raise a person above the chances of life, by making him feel that, let fate and fortune do their worst, they have no power to subdue him: whihc, once felt, frees him from excess of anxiety concerning the evils of life, and enables him, like many a Stoic in the worst times of the Roman Empire, to cultivate in tranquillity the sources of satisfaction accessible to him, without concerning himself about the uncertainty of their duration, any more than about their inevitable end. —J.S. Mill, Utilitarianism, ch. 2