Macroeconomia e Autorganizzazione: un nuovo contributo. Nota di discussione a: MASANAO AOKI - HIROSHI YOKISHAWA, Reconstructing Macroeconomics – A Perspective from Statistical Mechanics and Combinatorial Stochastic Processes

This discussion paper critically reviews a new book by Aoki and Yokishawa and presents some of the techniques adopted by the authors as a new approach to the foundations of macroeconomics. The paper discusses some of the main techniques of statistical mechanics relevant in this context, namely the Master Equation and the Polya Urn. The former is a key instrument for deriving some Keynesian results throughout the book, in particular the role of effective demand in stimulating the economy; additionally, it is used to assess the role and significance of uncertainty and to re-examine so-called «policy ineffectiveness», showing instead the positive contribution of an active economic policy. The Polya Urn is used to show demand saturation as a growth limiting factor and demand for new products as a growth-enhancing one, with the clear objective of linking the Keynesian principle of effective demand (short term) with a long-term growth theory.