Thinking Outside the Box: A New History of Edgeworth's and Pareto's Development of the Box Diagram

Polemical views are held among many historians as to whether the ‘original version’ of the Edgeworth box was drawn by Edgeworth, in his 1881 Mathematical Psychics, or Pareto, in his 1906 Manual of Political Economy. This study demonstrates that that polemic is largely attributable to a failure to consider the relationship between ‘trade’ flow oriented indifference curves drawn in Edgeworth’s Figures 1 and 5 and the implications of the relationship between those two diagrams for the definition of the origin of Edgeworth’s Figure 1. A new history of Edgeworth’s and Pareto’s contributions to the development of the Edgeworth box diagram is presented that highlights the intermediate role played by Pareto’s graph, from his 1902 article ‘On a New Error in the Interpretation of the Theories of Mathematical Economics’, which derives from Edgeworth’s Figure 5 except Pareto maps the indifference curves in the standard ‘allocation’ orientation.