In Der logische Aujbau der Welt, Carnap inaugurates a new philosophical discipline he calls “constitutional theory [Konstitutionstheorie]” and presents a particular “constitutional system [Konstitutionssystem]” in which “[all] scientific concepts are reduced to the ‘given’” (§3). This particular constitutional system proceeds from an “autopsychological basis” in which “the choice of basic elements is limited to such psychological objects that belong to only one subject” (§63). More precisely, the basic elements consist of the conscious psychological objects or “experiences” of a single subject (§64). Constitutional theory also envisions other possible constitutional systems, however: notably, a constitutional system with “general-psychological basis” in which scientific concepts are reduced to the experiences of all subjects (§63), and a constitutional system with “physical basis” in which scientific concepts are reduced to the fundamental concepts of physics (§62). What is common to every such constitutional system, then, is just the circumstance that all scientific concepts are to be defined in a single system on the basis of a few fundamental concepts: