Michael K. Green from the Philosophy Department presentated “The Ontologies of Economic Theories” at the AABSS Conference in Las Vegas, January 30-31, 2017. He examined the structure of inquiry underlying four economic traditions. Inquiry can proceed either by synthesis or analysis, and, in either case, can posit either one or many basic entities. Each of the above approaches has different types of opposition, identity, and causality. Neoclassical economics (Walras) develops an economic theory based on one homogeneous part, employs contrary opposition, posits an identity based on a consistent set of preferences, and uses exogenous causality. Austrian economics (von Mises) employs many distinctive elements, a contradictory opposition, an identity based upon comparative advantage, and endogenous causality that is restrained by exogenous causality. Keynesian economics employs a single unified whole, privative opposition, systemic identity arising from internal consistency, and endogenous causality. Classical economics (Shaikh) uses many different wholes, a relational, oscillating type of opposition, identity arising from the internal consistency of internal processes, and endogenous causality.