Abstract

Psychology was to be the capstone of Hermann Cohen’s never-completed System of Philosophy [1902 – 1912], encompassing his planned fourth volume and culminating his earlier critical studies of the transcendental logic of the natural sciences, ethics, and aesthetics. In opposition to empirical psychology, Cohen’s psychology was intended as a study of “the macrocosm of humanity in the microcosm of the cultural human.” It would reveal “the illusion of a closed unity of consciousness” even as it established a new “open” definition of the unity of humanity in relation to the future. As such, psychology depended on the critical work of his earlier volumes to avoid false definitions of substance in the natural sciences and of subjectivity in the ethical sciences and law. Psychology was the pivotal field for the most vexing problem of Cohen’s Marburg School, the relation of philosophy and science, and provides a lens for viewing the broader historical division of the natural sciences and humanities. The recent discovery of Ernst Cassirer’s notebooks from Cohen’s 1899 lectures on psychology allow us both to date Cohen’s planned psychology from the beginning of his late philosophy and to develop a clearer understanding of its reception.