Microeconomic structure determines macroeconomic dynamics: Aoki defeats the representative agent
Masanao Aoki developed a new methodology for a basic problem of economics: deducing rigorously the macroeconomic dynamics as emerging from the interactions of many individual agents. This includes deduction of the fractal/intermittent fluctuations of macroeconomic quantities from the granularity of the mezo-economic collective objects (large individual wealth, highly productive geographical locations, emergent technologies, emergent economic sectors) in which the micro-economic agents self-organize. In particular, we present some theoretical predictions, which also met extensive validation from empirical data in a wide range of systems: The fractal Levy exponent of the stock market index fluctuations equals the Pareto exponent of the investors wealth distribution. The origin of the macroeconomic dynamics is therefore found in the granularity induced by the wealth/capital of the wealthiest investors. Economic cycles consist of a Schumpeter creative destruction pattern whereby the maxima are \(\varLambda \)-shaped cusps. In between the \(\varLambda \)-cusps, the cycle consists of the sum of 2 crossing exponentials: one increasing (corresponding to the creation of the new) and the other one decaying (corresponding to destruction of the old). This unification within the same theoretical framework of short term market fluctuations and long term economic cycles offers the perspective of a genuine conceptual synthesis between micro- and macroeconomics. Joining another giant of contemporary sciencePhil Anderson 1972Aoki emphasized the role of rare, large fluctuations in the emergence of macroeconomic phenomena out of microscopic interactions and in particular their non self-averaging, in the language of statistical physics. In this light, we present a simple stochastic multi-sector growth model.
macroeconomics creative destruction economic growth