Rebel Cities. David Harvey

conversely, we cannot attempt such an explanation without reference to the general laws of motion (though Marx himself appears to do so in his account in Capital of the “independent and autonomous” financial and commercial crisis of 1847–48, or even more dramatically in his historical studies of The Eighteenth Brumaire and Class Struggles in France, where the general laws of motion of capital are never mentioned).11

      Secondly, the abstractions within Marx’s chosen level of generality start to fracture as the argument in Capital progresses. There are many examples of this, but the one that is most conspicuous, and in any case most germane to the argument here, relates to Marx’s handling of the credit system. Several times in Volume 1 and repeatedly in Volume 2, Marx invokes the credit system only to lay it aside as a fact of distribution that he is not prepared yet to confront. The general laws of motion he studies in Volume 2, particularly those of fixed capital circulation (including investment in the built environment) and working periods, production periods, circulation times, and turnover times, all end up not only invoking but necessitating the credit system. He is very explicit on this point. When commenting on how the money capital advanced must always be greater than that applied in surplus-value production in order to deal with differential turnover times, he notes how changes in turnover times can “set free” some of the money earlier advanced. “This money capital that is set free by the mechanism of the turnover movement (together with the money capital set free by the successive reflux of the fixed capital and that needed for variable capital in every labor process) must play a significant role, as soon as the credit system has developed, and must also form one of the foundations for this.”12 In this and other similar comments it is made clear that the credit system becomes absolutely necessary for capital circulation, and that some accounting of the credit system has to be incorporated into the general laws of motion of capital. But when we get to the analysis of the credit system in Volume 3, we find that the interest rate (a particularity) is set jointly by supply and demand and by the state of competition—two specificities that have earlier been totally excluded from the theoretical level of generality at which Marx prefers to work.