is an art historian and the head of the Interdisciplinary Center »Art and Esthetics« at Freie Universität Berlin. His research focus is on French art of the 19^thand early 20^thcentury, US-American art of the post-1945 era and on modern aesthetics. He is also head of the subordinated project of »Mittelbarkeit und Unmittelbarkeit in der Kunst der Moderne« as part of a collaborate research project funded by the »Deutsche Forschungsgemeinschaft« (DFG) on »Ästhetische Erfahrung im Zeichen der Entgrenzung der Künste«, a project he also supervises.