The Logical Structure of the World (Der logische Aufbau der Welt)

A systematic treatise, usually called simply the Aufbau, in which Carnap tries to show how all the concepts of science could be rationally reconstructed from a narrow base of experience. He calls the result a constitution system. For the base he chooses elementary experiences, whole momentary slices of one person's experience, and a single basic relation, the remembered similarity between two of them. By a technique he calls quasi-analysis he builds sense qualities and sense fields from this, then physical objects, then other minds, and finally cultural and social objects. He calls this starting point methodological solipsism, insisting it is a choice of method, not a claim that only one's own experience exists. A central idea is that scientific knowledge concerns structure, so that every concept can in principle be defined by purely structural descriptions. The book was a key text of the Vienna Circle. Quine and Goodman later argued that the reconstruction cannot be completed as planned.

It is the most ambitious attempt to carry out the empiricist programme with modern logic, and it explains what Quine and later analytic philosophers were reacting against.