 Thus we see Marty defending the Brentanian conception of philosophy in general and metaphysics in particular, with an appeal to Aristotle, who was indeed Brentano’s life-long guide through the labyrinth of philosophy. Moreover, though Marty’s publications were mainly concerned with applying Brentanian descriptive psychology to the study of language, he lectured on all the branches of philosophy, both theoretical and practical, as well as history of philosophy. (See Bokhove and Raynaud 1990, 247–250.) It will be seen further below that metaphysics was indeed a very important concern of his.