Fluctuations, Risks and Uncertainty in Economics

This note aims at preparing a fundamental framework for our dynamics models taking true uncertainty concept into consideration, and it states the following. First, the rationalities supposed in non-neoclassical economics such as economics of complexity or economics of anomalies are wider sense concepts than that supposed in rational expectation hypothesis.But these schools coincide with each other in the viewpoint of the assumption of stationarity in the economic processes or ergodicity in the stochastic processes. Their main difference just exists between their scopes of stationarity or those of ergodicity. Second, their difference above is not a matter in the face of unpredictable economic shocks, which interrupt stationary states in any sense and should not be in any category of ergodic stochastic processes. Such a shock has a tendency to enlarge uncertainty consciousness in the mental states of the economic units whether another economic shock would come or not in the near future. Increased uncertainty might prevents a person from his rationally expecting, or if we support economics of complexity, we would think that enlarged uncertainty consciousness in human mind might invalidate the several buffers such as inventories, money and credit system, by which economic units deal with some fluctuations in normal ergodic processes. Lastly, however, uncertainty in economics is just a psychological phenomena which we may almost neglect in an ordinary way although it occasionally has serious influences on our economy. Accordingly, we should never regard uncertainty in our models as a universal factor but as a peculiar thing after an economic shock.

研究ノート (Note)