Suchergebnisse

Two variables are said to be cointegrated when they move closely together over time, after proper scaling. Cointegration was taken to be the statistical expression of the notion of equilibrium in economics. But is it still possible to talk of cointegration when 'disequilibrium' economics prevail? We argue that it is, and that the duality is strongest between cointegration theory and economic theories of non‐clearing markets. By setting up a simple generic non‐parametric model, it is shown that Clower's dual decision hypothesis is a more direct and natural expression of the notion of cointegration than long‐run equilibrium is. With sticky prices, quantities (e.g. consumption and income) move together more closely than they would otherwise. As a by‐product, the model gives rise to (and justifies from an economics standpoint) a recent statistical approach to modelling economic time series. An observational equivalence between two econometric models is also presented.

This note shows that much conventional macro‐economic literature uses two inconsistent definitions of equilibrium in the commodity market. Equilibrium is defined as income equalling expenditure when deriving the IS curve; but when overall equilibrium is treated the requirement for equilibrium is that planned supply equals planned demand. The note shows that these inconsistent definitions lead to a confusing and often erroneous exposition of disequilibrium behaviour.

Abstract
Most philosophers of economics are hostile towards neoclassical economics in general and general equilibrium theory in the vein of Arrow and Debreu in particular. Especially the latter's dismissal is justified by pointing out its lack of direct relevance for an understanding of real economies. Many recommend a more pragmatic approach along the lines of Keynes instead. The criterion of scientific legitimacy underlying this approach derives from a philosophy of science developed along the lines of Popper and Lakatos. They, however, neglect the importance of conceptual problems and of the choice of adequate 'language-systems' in science. Since these conceptual and 'linguistic' aspects may be able to explain and to justify the rationale of the Arrow-Debreu approach, I recommend the more balanced philosophies of Carnap and Laudan, in which conceptual as well as empirical problems are allowed for, as a framework for methodological appraisal. I explain why such a balanced view is obstructed for most philosophers of economics and advocate a moderate pluralism leaving room for different theories, methodologies and language-systems, depending on the scientific aims that are pursued.

In his 1989 Cambridge doctoral dissertation,The Concept of Equilibrium in Neoclassical Theory, Franco Donzelli observed that, "The history of the neoclassical approach over the last one hundred and twenty years can be interpreted as a history of the relationship between instantaneous and stationary equilibrium models, on the one hand, and of the developments internal to either class of models, on the other" (Donzelli 1989, p. 31).