- 著者
-
森岡 真史
- 出版者
- 経済理論学会
- 雑誌
- 季刊経済理論 (ISSN:18825184)
- 巻号頁・発行日
- vol.41, no.3, pp.54-65, 2004-10-20 (Released:2017-04-25)
This paper critically investigates the classical preposition that the natural prices are the center of gravitation towards which market prices should move through the equalization process of industries' rates of profit. While intensively studied in 1980s and early 90s, in recent years concern for this subject seems to have declined mainly because a series of studies showed that it was by no means easy to construct a model in which rates of profit tended to be equalized. The purpose to take up this problem here is to reconsider the logic of classical argument on gravitation and to analyze systematically the dynamic nature of cross adjustment process where differentials in profit rates trigger the change of production and excess demand in each industry leads to the change of market price. In spite of the erroneous reasoning about the relation between price deviations and profit deviations, if the positive profit deviation in one industry always leads fall of its market price, the classical argument on gravitation is basically valid. The real flaw in the classical argument is that it overlooks the derived change of demand and thus fails to connect price-production movements with the balance between production and demand. This flaw can be removed by combining the adjustment of production caused by differentials in profit rates with the price movement reacting to excess demand. Thus whether the classical argument is right or wrong eventually depends on the dynamic nature of cross adjustment process. Except for few particular cases, cross adjustment brings about at best the permanent fluctuation of production and prices within a closed orbit and quite often leads to their unstable movement. The analysis in this paper demonstrates the above by multi-sector models with various assumptions on time and production period. Models consisting of three or more sectors are more likely to be instable than two-sector models. Furthermore, cross adjustment always causes instabity in discrete time models. Particularly notable is the fact that introduction of the budget constraint does not contribute to the stability of cross adjustment. It is possible to give classical cross adjustment asymptotic stability by introducing 'neo-classical' price substitution effect or 'Keynesian' quantity adjustment. However, considering the deep differences among classical, neo-classical and Keynesian economics in their theories of production adjustment, their mechanical conjugation is of little theoretical significance, even though cross adjustment extended by such conjugation may gain stability. It would be hasty to interpret the above results as 'refutation' of the classical preposition on equalization of profit rates. There are many prepositions or hypothesis in economics lacking logical 'proof' but frequently used for their usefulness or as stylized empirical fact. For the time being, the classical preposition may be regarded one of those prepositions. The model analysis in this paper throws serious doubts not to the classical preposition itself but rather to its underlying mechanisms of price-production adjustment supposed by classical economists. Especially, the mechanisms that firms increase (decrease) their production when their profit rates are above (below) the average level does not sufficiently refrect one of the most important features of capitalist economy that capitalist firms are usually under demand constraint. At any rate, future search of theoretical foundation of profit equalization should start from the different vision on the fluctuation process triggered by differentials in profit rates.