Sociological theory and historical explanation are both characterized by the competition of different apporoaches. Concerning the methodological part, there is a dispute about models of nomological and rational explanation; concerning the sociological part, on the most general level, there is a debate on the differences between a theory of action, a systems theory, and a learning theory. The model of rational explanation, however, does not succeed in safeguarding a character of its own. The three approaches of sociological theory show some serious insufficiencies, which questions their application to explain historical developments. Instead,a theory of evolution is presented, which distinguishes itself from other attemps of this kind. The starting point are the challenges of the environment, which force a class of individuals to develop strategies to maintain its continuity. An additional theorem states the conditions for a higher or lower capacity to master the problems of maintaining continuity. Subjects of continuity-maintenance should be not systems, but classes of individuals. „Continuity“ refers to an existing standard of life-chances. The environment is represented by all matters of fact, inside and outside a system. The application of this theory to MAX WEBER’s explanations of the fall of Rome and of the rise of capitalism proves the fruitfulness of the evolutionary approach.