One of the founders of the Gestalt school of psychology, Köhler also wrote The Place of Value in a World of Facts (1938), the result of his William James lectures delivered at Harvard in 1934. Köhler attempted to work out a theory of value, including aesthetic value, on the basis of the phenomenally objective gestalt-quality which he called ‘requiredness’. One part of a visual field, for example, may demand completion in some specific way, rather as a melody may require resolution.