 His first publications were in logic, a subject he had formally learned at the University of Vienna from Laurenz Müllner and possibly Friedrich Jodl, and in the history of political economy, on which his father had also written. The papers on logic (see below) examined different kinds of identities and the principle of duality stimulated by Schröder; they included one paper co-authored with his friend and second wife, Olga Hahn, sister of the mathematician Hans Hahn. In the history of political economy, topics included the history of money and economic organizations in antiquity, and his publications included textbooks and readers either co-authored or co-edited with his first wife Anna Schapire-Neurath. Not surprisingly, his subsequent theorizing on the social sciences and his contributions to debates in logical empiricism integrated both disciplines. With the mathematician Hans Hahn and the physicist Philip Frank, around 1910 Neurath formed in Vienna a philosophical discussion group devoted to the philosophical ideas about science of Vienna’s phenomenologist Ernst Mach and the French conventionalists Pierre Duhem, Abel Rey and Henri Poincaré. A great deal of philosophical and scientific concerns and insight were already in place in Neurath’s thinking and projects. With a grant from the Carnegie Endowment for International Peace, a subsequent study of the Balkan wars before World War I led to his theory of war economy as a natural (non-monetary) economy, or economy in kind.