special traits, according to such differences of race and of civilizations. And so for every kind of human production, for letters, music, the arts of design, philosophy, the sciences, state industries, and the rest. Each has some moral tendency for its direct cause, or a concurrence of moral tendencies; given the cause, it appears; the cause withdrawn, it disappears; the weakness or intensity of the cause is the measure of its own weakness or intensity. It is bound to that like any physical phenomenon to its condition, like dew to the chilliness of a surrounding atmosphere, like dilatation to heat. Couples exist in the moral world as they exist in the physical world, as rigorously linked together and as universally diffused. Whatever in one case produces, alters, or suppresses the first term, produces, alters, and suppresses the second term as a necessary consequence. Whatever cools the surrounding atmosphere causes the fall of dew. Whatever develops credulity, along with poetic conceptions of the universe, engenders religion. Thus have things come about, and thus will they continue to come about. As soon as the adequate and necessary condition of one of these vast apparitions becomes known to us our mind has a hold on the future as well as on the past. We can confidently state under what circumstances it will reappear, foretell without rashness many portions of its future history, and sketch with precaution some of the traits of its ulterior development. VIII. General problem and future of history. Psychological method. Value of literature. Purpose in writing this book