This is a translation of an early essay by the German philosopher Nicolai Hartmann (1882–1950). In this 1923 essay Hartmann presents many of the fundamental ideas of his new critical ontology. He summarizes some of the main points of his critique of neo-Kantian epistemology, and provides the point of departure for his new approach in an extensive criticism of the errors of the classical ontological tradition. Some of these errors concern the definition of an ontological category or principle, and others (...) concern the relations among categories themselves. The outline for the new ontology is sketched through the correctives Hartmann appends to the treatment of each error, prefiguring his mature ontological system. (shrink)