But here’s the catch. In a working day (which in the mid-nineteenth century could be sixteen hours long), workers can produce goods worth more than a subsistence wage. This ‘surplus labour’ is the source of the capitalists’ profits. Machines, however, do not offer surplus labour – in a competitive market, industrialists will have to buy them at a cost equal to the value of the goods they can generate. So mechanization renders workers unemployed, but does not rescue the capitalists’ profits.
© Philip Ball – Critical Mass (excerto) – Arrow Books