With regard to the rate of profit (s/C), where s = surplus-value, and C = total capital laid out), and the factors that influence it, the fundamental relation that Marx establishes (in chapter 3 of volume 3 of Capital) is π = δ(v/C), in which π = rate of profit, δ = rate of surplus-value (s/v), and v = variable capital (capital laid out as wages): “The rate of profit is thus determined by two major factors; the rate of surplus-value and the value composition of the capital.” The rate of profit increases in function of a rise in the rate of surplus-value, and falls in function of an increase in the constant part of capital with respect to variable. Marx’s purpose in this chapter was to delink the rate of surplus-value from the rate of profit: to show that the same rate of surplus-value can find expression as different rates of profit, and that the same rate of profit can arise from different rates of surplus-value.

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