 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 was metaphysically neutral. One of the many possible logical constructions —borrowing Russell’s terminology—or constitution systems of knowledge was to accommodate the epistemic value of individual experience while preserving the objective form of scientific knowledge (Friedman 1999). It is there that in order to represent experience scientifically, he chose, following Schlick, Gestalt theory. Experience contributed a complex holistic stream—a ‘true’, ‘organic’ whole—out of which the elementary empirical concepts must be abstracted, by the process he called quasi-analysis. Unlike for Stumpf, but like for Wertheimer and Köhler, for Carnap elementary sensations were only abstractions—he wrote of quasi-analysis through classes of recollected experiences—from experiential Gestalts. In the book he explicitly referred to Köhler’s article ‘Gestaltprobleme und Anfänge einer Gestalttheorie, Übersichtsreferat’ (1925) and Wertheimer’s survey Ueber Gestalttheorie (1925) (Carnap (1928), sects. 62 and 109; besides Husserl’s, the influence of Meinong’s Gestalt-based philosophy deserves careful exploration).