 Brentano’s tendency to offer psychological explanations is shown also in his approach to the history of philosophy, in particular in his explanations of the mechanisms that explain the historical development in this discipline. In his text The Four Phases of Philosophy and Its Current State (1998) he defended the metaphilosophical thesis that progress in philosophy can be explained according to principles of cultural psychology. According to Brentano, philosophical progress takes place in circles. He divides the whole history of philosophy in three periods (ancient, medieval, and modern philosophy), each of which can, according to him, be subdivided in four phases. The first is a creative phase of renewal and ascending development; the other three are phases of decline, dominated by a turn towards practical interests, by scepticism, and finally by mysticism. After the fourth phase, a new period begins with a creative phase of renewal. 