During 1974-1975, he was visiting assistant professor at SUNY Albany. In 1976 he became assistant professor at the University of Maryland, was promoted to associate professor in 1982 and full professor in 1991. In 2004 he was accorded the title of Distinguished University Professor. He has also been visiting professor at other US institutes, including the Johns Hopkins University and Columbia University. He has also held visiting appointments in other countries, such as England (University of London and University of Kent), New Zealand (University of Canterbury), France (Université de Rennes), Belgium (Université Libre de Bruxelles), Portugal (Universidade de Lisboa) and Switzerland (Conservatorio della Svizzera Italiana). During 2010-2011 he held an International Francqui Chair at the Katholieke Universiteit Leuven (Belgium), and in 2011 received the Premio Internazionale of the Società Italiana d'Estetica.