“It is now time to finish with the question of the value resulting from the growth of the productive forces,” Marx announces.

We have seen that a rise in productivity creates both a greater use value (more physical product) and a greater surplus value (by cheapening the cost to the reproduction of labour). (The result is the same as that produced by an absolute extension of the working period.)

If we say that per-worker necessary labour-time is given (say 6 hours), and that it is impossible to lengthen the working day (which stands, say, at 12 hours), then an increase in absolute labour-time is only possible by employing more workers (such that “the real working day is simultaneously multiplied instead of only lengthened”.

More (pdf, 79 KB): The Chapter on Capital: Part 16: The Transformation of Surplus Labour into Profit (III): The Effect of Rising Social Productivity (pp. 386-398)