production, but not lower the general profit rate (the grand-average profit rate) as a whole. Apart from a few exceptional cases, Ricardo claimed, the average rate of profit could only fall if wages rose. In Capital, Karl Marx criticized Ricardo's idea. Marx argued that, instead, the tendency of the rate of profit to fall is "an expression peculiar to the capitalist mode of production of the progressive development of the social productivity of labor". Marx never denied that profits could contingently fall for all kinds of reasons, but he thought there was also a structural reason for the TRPF, regardless of current market fluctuations. Productivity By raising productivity, labor-saving technologies can increase the average industrial rate of profit rather than lowering it, insofar as fewer workers can produce vastly more output at a lower cost, enabling more sales in less time. Ladislaus von Bortkiewicz stated: "Marx’s own proof of his law of the falling rate of profit errs principally in disregarding the mathematical relationship between the productivity of labour and the rate of surplus value." Jürgen Habermas argued in 1973–74 that the TRPF might have existed in 19th century liberal capitalism, but no longer existed in late capitalism, because of the expansion of "reflexive labor" ("labor applied to itself with the aim of increasing the productivity of labor"). Michael Heinrich has also argued that Marx did not adequately demonstrate that the rate of profit would fall when increases in productivity are taken into account. Contingency How exactly the average industrial rate of profit will evolve is either uncertain and unpredictable, or it is historically contingent; it all depends on the specific configuration of costs, sales and profit margins obtainable in fluctuating markets with given technologies. This "indeterminacy" criticism revolves around the idea that technological change could have many different and contradictory effects. It could reduce costs, or it could increase unemployment; it could be labor-saving, or it could be capital-saving. Therefore, so the argument goes, it is impossible to infer definitely a theoretical principle that a falling rate of profit must always and inevitably result from an increase in productivity. Perhaps the law of the tendency of the rate of profit to fall might be true in an abstract model, based on certain assumptions, but in reality no substantive, long-run empirical predictions can be made[?]. In addition, profitability itself can be influenced by an enormous array of different factors, going