In the Aufbau Carnap associated Watson’s behaviorism with a physicalist basis for a construction system, whereas Gestalt psychology was better suited to provide an empirical basis for the epistemological system (which was to reflect the origin of the concepts in our system of knowledge) (Carnap 1928). Carnap was concerned, in a neo-Kantian fashion, with the question of the constitution of the world; and he tried to combine the strengths of empiricist and Kantian epistemologies in a system that w