Scrutinizes and criticizes modern tendencies in philosophy of history wherein subjective elements are counterposed to the classical doctrines of Leopold von Ranke. The author labels two types of subjectivism, "presentism" and "perspectivism"; the former identified with Croce, Simmel, and others in philosophy, with Beard, Becker, and others in historiography; and the latter with Karl Mannheim's sociology of science in which he pushed Marx's notion of the social determination of human knowledge to a point of "subjective arbitrariness." Contrary to these subjective ideas, Schaff expounds the Marxian concept of "the objective unveiling of the past in the course of historical development." This concept suffices to account for the need to rewrite history as the historical past becomes more fully known and as known facts take on new coloration.