Economics as “logic” of rational behaviour
The Cowles Commission series of books that defined the paradigm of modern neoclassical economics unwillingly paved the way for upholding the claim to analytical truth and empirical validity at the same time.
Despite the fact that many of the Cowles Commission series of texts were written in the Bourbaki style of mathematical formalism, the books were understood to be claiming to present self-evident truths about the real world. To name just two prominent examples, the papers in Activity Analysis of Production and Allocation edited by Tjalling C. Koopmans (1951) or Gerard Debreu’s (1959) Theory of Value were interpreted by neo-classical economists as theories about the world, that is, they were not treated as examples of mathematical formalism but, in the spirit of classical Euclidean geometry, as expressing undeniable truths about the real world.In this regard, modern economists repeated the philosophical blunder of Hobbes and philosophical rationalists who also believed that they could make empirical claims for theories developed “more geometrico”. Only an empirical turn of economics away from a rationalist Hobbesian “logic” (“Entscheidungslogik”) to an empiricist social psychology of decision-making in interactive situations (“Marktsoziologie”) can heal this deficiency (see Albert 1967 [1998]).
Nomological hypotheses about real economic behaviour can, of course, be represented by systems of axioms that can then be studied analytically with logical and mathematical methods. However, the truth of such theories that make a nomological claim is tested (a posteriori) through their implications rather than justifying the implications by the (a priori) truth of the axioms.
As far as this is concerned the practice of neo-classical economic theory is still much closer to the older Hobbesian/Euclidean tradition of reasoning more geometrico than to modern empirical science. That the misconceived ideals of behavioural geometry linger on to the present day is mostly due to the fact that economics is still conceived as dealing with a normative conception of “rational” behaviour rather than with empirical behaviour per se.