Like his predecessors, Marx totally neglected the possibility of durable technological progress and steadily increasing productivity, which is a force that can to some extent serve as a counterweight to the process of accumulation and concentration of private capital.
My conclusions are less apocalyptic than those implied by Marx’s principle of infinite accumulation and perpetual divergence (since Marx’s theory implicitly relies on a strict assumption of zero productivity growth over the long run).
For Marx, the central mechanism by which “the bourgeoisie digs its own grave” corresponded to what I referred to in the Introduction as “the principle of infinite accumulation”: capitalists accumulate ever increasing quantities of capital, which ultimately leads inexorably to a falling rate of profit (i.e., return on capital) and eventually to their own downfall. Marx did not use mathematical models, and his prose was not always limpid, so it is difficult to be sure what he had in mind. But one logically consistent way of interpreting his thought is to consider the dynamic law β = s / g in the special case where the growth rate g is zero or very close to zero.
In Marx’s mind, as in the minds of all nineteenth- and early twentieth-century economists before Robert Solow did his work on growth in the 1950s, the very idea of structural growth, driven by permanent and durable growth of productivity, was not clearly identified or formulated.... Today we know that long-term structural growth is possible only because of productivity growth. But this was not obvious in Marx’s time, owing to lack of historical perspective and good data.
That Marx actually had a model of this kind in mind (i.e., a model based on infinite accumulation of capital) is confirmed by his use on several occasions of the account books of industrial firms with very high capital intensities. In volume 1 of Capital, for instance, he uses the books of a textile factory, which were conveyed to him, he says, “by the owner,”
Marx was also an assiduous reader of British parliamentary reports from the period 1820–1860. He used these reports to document the misery of wage workers, workplace accidents, deplorable health conditions, and more generally the rapacity of the owners of industrial capital. He also used statistics derived from taxes imposed on profits from different sources, which showed a very rapid increase of industrial profits in Britain during the 1840s. Marx even tried—in a very impressionistic fashion, to be sure—to make use of probate statistics in order to show that the largest British fortunes had increased dramatically since the Napoleonic wars.
The problem is that despite these important intuitions, Marx usually adopted a fairly anecdotal and unsystematic approach to the available statistics.
Marx seems to have missed entirely the work on national accounting that was developing around him, and this is all the more unfortunate in that it would have enabled him to some extent to confirm his intuitions concerning the vast accumulation of private capital in this period and above all to clarify his explanatory model.
No doubt Marx’s literary talent partially accounts for his immense influence.
In Chapter 6 I return to the theme of Marx’s use of statistics. To summarize: he occasionally sought to make use of the best available statistics of the day (which were better than the statistics available to Malthus and Ricardo but still quite rudimentary), but he usually did so in a rather impressionistic way and without always establishing a clear connection to his theoretical argument.