Key Arguments

• The length of the working day represents the extensive magnitude of labor
• The intensity of labor represents the intensive magnitude (expenditure of energy in a given time)
• The productivity of labor determines the quantity of product yielded by the same quantity of labor

Source Quotes

I assume (1) that commodities are sold at their value, (2) that the price of labour-power occasionally rises above its value, but never sinks below it. On these assumptions, we have already found that the relative magnitudes of surplus-value and of price of labour-power are determined by three circumstances: (1) the length of the working day, or the extensive magnitude of labour, (2) the normal intensity of labour, or its intensive magnitude, whereby a given quantity of labour is expended in a given time and (3) the productivity of labour, whereby the same quantity of labour yields, in a given time, a greater or a smaller quantity of the product, depending on the degree of development attained by the conditions of production. Very different combinations are clearly pos sible, since one of the three factors can be constant while the other two vary, two factors can be constant while one varies, and, finally, all three may vary.

Key Concepts

• relative magnitudes of surplus-value and of price of labour-power are determined by three circumstances
• length of the working day, or the extensive magnitude of labour
• normal intensity of labour, or its intensive magnitude
• productivity of labour

Context

Marx outlining the three fundamental variables that he will permute in the subsequent analysis to show how surplus value changes