 Whereas Carnap aimed at rational reconstructions, another member of the Vienna Circle, Otto Neurath, favored a more naturalistic and pragmatic approach, with a less idealized and reductive model of unity. His evolving standards of unity were generally motivated by the complexity of empirical reality and the application of empirical knowledge to practical goals. He spoke of an “encyclopedia-model”,opposed to the classic ideal of a pyramidal, reductive “system-model”. The encyclopedia-model took into account the presence within science of uneliminable and imprecise terms from ordinary language and the social sciences and emphasized a unity of language and the local exchanges of scientific tools. Specifically, Neurath stressed the material-thing-language called “physicalism”, not to be confounded with the emphasis on the vocabulary of physics. its motivation was partly epistemological and Neurath endorsed anti-foundationalism: No unified science, like a boat at sea, would rest on firm foundations. The scientific spirit abhorred dogmatism. This weaker model of unity emphasized empiricism and the normative unity of the natural and the human sciences.