 A stronger reductive model within the Vienna Circle was recommended by Rudolf Carnap in his The Logical Construction of the World (1928). While embracing the Kantian connotation of the term “constitutive system”, it was inspired by recent formal standards: Hilbert’s axiomatic approach to formulating theories in the exact sciences and Frege’s and Russell’s logical constructions in mathematics. It was also predicated on the formal values of simplicity, rationality, (philosophical) neutrality and objectivity associated with scientific knowledge. In particular, Carnap tried to explicate such notions in terms of a rational reconstruction of science in terms of a method and a structure based on logical constructions out of (1) basic concepts in axiomatic structures and (2) rigorous, reductive logical connections between concepts at different levels.