Everything folded before the great tasks of philosophical and religious rebirth. Sharp thinking was in fact not my inclination until then; on the contrary, it was rather unpleasant to me. Only Brentano’s iron discipline made the need for logical clarity and consistency second nature. [ ... ] The thesis which he defended in his habilitation, that the true philosophical method is none other than the one of natural science, was and remained for me a guiding star.2