Les crises économiques du capitalisme (de marché) sont essentielles dans la pensée de Karl Marx. Elles sont cruciales dans sa vision de l'avenir historique. Et il en fournit des explications. Celles-ci permettent-elles de rendre compte de la crise récente (et des autres) ? Des auteurs ont essayé d'expliquer cette dernière grâce à cette inspiration, plus précisément à l'aide de considérations sur la baisse du taux de profit. Ont-ils réussi ?

Marx a non pas une mais deux théories des crises économiques : la question de la « baisse tendancielle du taux de profit » et les « crises de réalisation ». Dans sa vision d'ensemble, la première est beaucoup plus importante.

Several authors have attempted to provide explanations of the present crisis with arguments which find their original inspiration in Marx's viewpoint. Marx had two theories of economic crises. The “realisation crises” have been incorporated in Keynesian theory. More basic for this author was the “tendency law of the fall of the rate of profit”, and some observers argue that such a fall has been observed since 1965 or 1968. However, historically profits have fluctuated without showing long run trend. Worst, there are many possible definitions of “the” profit rate, and at each time some fall and some others go up. The relevant one depends upon the theory of the effect of the profit rate on variables like unemployment, global income, etc. Marx has no such theory, and the several ones presented in this contemporary literature all suffer from a number of elementary logical flows such as: firms behavior is rarely to “recover” a given profit rate; if some of their actions (increase prices, decrease real wages) raise their profits, why did they not do it before the rate's fall? such actions do not explain by themselves unemployment nor inflation; the discarding of less profitable equipment does not increase profit; all these actions cannot transform a progressive rate's fall into an abrupt crisis like that of 1974; the reasonings are presented as if capitalists were a single firm and they omit competition (which was not the case of Marx); that is in particular the case for the so called “fordism “ theory. Furthermore the eventual fall of the rate of profit is not explained, and Marx's own explanations are full of defects (he saw six of them). Ethical motivations are not well served if they are allowed to subvert elementary logics in the arguments.