 Neurath developed and generalized his early practical, theoretical and meta-theoretical concerns about social theory (with his talk of a ‘universal science’ in 1910, a ‘unified construction of economic science’ in 1917 and a ‘unified program’ for socialization in 1919) as a philosophy of the human sciences. These included psychology and sociology, which he treated in contrast with the natural sciences. His study of the foundations of the social sciences extended to import normative constraints set by logical empiricism, e.g., the emphasis on foundations and the logical and empiricist considerations with respect to physicalism. This contribution determined his qualifications to ideals of unity of the sciences, especially involving the relation between the natural and the human sciences, and to ideals of shared scientific methodology.