This essay describes correspondence in the late 1930s among John Dewey, Charles Morris, Otto Neurath and Rudolf Carnap concerning Dewey’s contributions to Neurath’s International Encyclopedia of Unified Science. The essay argues that Dewey especially viewed the Encyclopedia as a socially and culturally important project, even though he had reservations about logical empiricism’s approach to understanding values in science and scientific method. Around Dewey’s specific objections to intertheoretic reductionism, this paper argues, were clustered more general concerns about values in science, in culture, and the need to oppose the popular neo-Thomist critique of science and scientific philosophy.