Karl Mittermaier’s investigation into and his analysis of the methodology and philosophy of economics is relevant to social sciences in general and the various subdisciplines of economics, such as law and economics. His pragmatic stance on a free market system and on Classical liberalism, which align with those of Adam Smith, derive from an eschewal of extreme forms of rationalism and empiricism. He charts a course toward a cogent subjectivism in economics by addressing the fundamental philosophical questions about the meaning of universal terms used in theory, navigating the realist and nominalist attitudes. The practical implications of his approach are formulated in the distinction he makes between ex ante facts and ex post facts.