So far as the variable capital is concerned — and this is most important, because it is the source of surplus-value, and because anything which conceals its relation to the accumulation of wealth by the capitalist serves to mystify the entire system — matters get cruder or appear to the capitalist in the following light: A variable capital of £100 represents the weekly wage of, say, 100 labourers. If these 100 labourers weekly produce 200 pieces of a commodity = 200C, in a given working-time, then 1C — abstracted from that portion of its cost-price which is added by the constant capital, costs £100/200 = 10 shillings, since £100 = 200C. Now suppose that a change occurs in the productiveness of labour. Suppose it doubles, so that the same number of labourers now produces twice 200C in the time which it previously took to produce 200C. In that case (considering only that part of the cost-price which consists of wages) 1C = £100/400 = 5 shillings, since now £100 = 400C. Should the productiveness decrease one-half, the same labour would produce only 200C/2 and since £100 = 200C/2, 1C = £200/2 = £1. The changes in the labour-time required for the production of the commodities, and hence the changes in their value, thus appear in regard to the cost-price, and hence to the price of production, as a different distribution of the same wage for more or fewer commodities, depending on the greater or smaller quantity of commodities produced in the same working-time for the same wage. What the capitalist, and consequently also the political economist, see is that the part of the paid labour per piece of commodity changes with the productivity of labour, and that the value of each piece also changes accordingly. What they do not see is that the same applies to unpaid labour contained in very piece of the commodity, and this is perceived so much less since the average profit actually is only accidentally determined by the unpaid labour absorbed in the sphere of the individual capitalist. It is only in such crude and meaningless form that we can glimpse that the value of commodities is determined by the labour contained in them.