The Relation of Neoclassical Economics to other Disciplines: The case of Physics and Psychology

Since the emergence of the classical school, the scientific ideal of physical sciences has been a constant influence on economic theory and method. Its influence is still present in contemporary neoclassical economics. Similarly to the case of physics, classical economists were very open in incorporating psychological elements in the economic discourse. This openness towards psychology continued with prominent Marginalist economists, like Jevons and Edgeworth, who were eager to draw from psychological ideas found in earlier authors. In the first decades of the 20th century, a major conceptual change in economics took place which is also known as the Paretian turn. This conceptual change, initiated mainly by Vilfredo Pareto, and completed, in the first decades of the 20th century, by J. Hicks, R. Allen and P. Samuelson, attempted to remove all psychological notions from economic theory. The legacy of the Paretian turn can still be identified in the significant reluctance of the contemporary orthodox economic theory to incorporate the findings of the new behavioral economics, a field with a discernable psychological bent. This chapter argues that the history of the relation of those two subjects to economics can lead to some potentially useful observations concerning the nature of contemporary neoclassical economics. It will also be maintained that the relationship of neoclassical economics to physics ultimately constrained its interaction with psychology.