ABSTRACT
Keynesian theory signified a departure from traditional business cycle theories, 1 especially by stimulating the construction of a series of models. It seems to the present author, however, that the analysis of fluctuations should begin from a more fundamental reappraisal of the concept of stability, and its meaning in various contexts (Section 1). The approach in terms of models of fluctuations will then be considered, starting from an example and its subsequent developments (Section 2). We shall then set out to explain fluctuations which arise from today's large-scale macroeconomic models, with special emphasis on the respective roles of the internal dynamics of an economic system, of partly endogenous and of wholly exogenous factors (Section 3). Finally, the possibility of controlling fluctuations, in the context of modern methodology based on these models, will be investigated.
