 In his famous paper of 1950, “Empiricism, Semantics, and Ontology,” Carnap made his two-tiered view of inquiry quite explicit. Starting from the problem of the existence of abstract entities, Carnap distinguished internal questions, that is, questions that can arise and be answered within a particular logico-linguistic framework, from external questions, that is, meta-level questions about which framework to prefer. External questions cannot be answered in the same, disciplined manner as internal, for choice of framework is ultimately a pragmatic decision based on the expected fertility of using one framework rather than another. Although it is difficult to equate Carnap’s fruitfulness decisions with Kuhn’s revolutionary breaks (Kuhn 1993, 313f), Carnap regarded his vision of science as similar to Kuhn’s, and he liked the manuscript of Structure that Kuhn submitted to the International Encyclopedia of Unified Science, as George Reisch (1991) has shown. Thus the clash of Kuhn’s work with that of Carnap and the positivist movement has been exaggerated.