For Marx, the distinction between surplus value and profit is that the rate of surplus value equals the surplus value over variable capital (S/V) while the rate of profit (r) equals surplus value over variable and constant capital combined (r=S/(C+V)). In some sense, the story Marx tells in chapter nine has to be an equilibrium story, because it's a story about how you get from a uniform rate of surplus value to a uniform rate of profit. The uniform rate of profit is determined simply as the average of the rates of profit which would obtain if the rate of surplus value were held constant (which Marx knew not to be the case). The justification, presumably, is that the rate of surplus value is not "apparent", even if more fundamental than the rate of profit. So, capitalists in a world with varying organic compositions of capital would reach an equilibrium of sorts with a constant rate of profit, not a constant rate of surplus value.
But why in the world would a capitalist calculate his rate of profit on a base of unobservable values? (And if capitalist calculations don't enter into it, then why assume that the rate of profit will be constant?) The rate of profit, from the capitalist's point of view, is calculated on a base of what Marx in this chapter refers to as a "cost price". How does Marx derive the "cost price" in this chapter? By adding variable capital and an arbitrarily chosen amount of constant capital used up in the production process. The problems here seem to be several:
(1) It is simply assumed that the cost price is exactly proportional to the value "used up" in production. But this is recisely the simple equation between price and value that the chapter repudiates.
(2) If you calculate the rate of profit as a capitalist would, that is, as the difference between the price of a commodity and its cost-price on a base of its cost-price, then the rate of profit is not constant in Marx's calculations. Instead, in Marx's examples in chapter 9, THAT rate of profit would vary from about 24% to a bit shy of 150%. So, it turns out, the rate of profit that capitalists would care about is not uniform. In which case, why go through the exercise of deriving a constant "r" in the first place?
(3) To what earthly use can a rate of profit calculated on an unobservable base be put? What does it matter if the rate of profit falls, if that falling rate of profit is not calculated on a base of the price costs of the firm? What kind of theory of the firm can be developed based on a rate of profit that is neither known to nor relevant to the capitalist?
I confess that I don't understand the last point of Kliman's rebuttal. Perhaps somewhere in here I've smuggled in "the bizarre premise that input and output prices must be equal", but I honestly don't see where. (I do hold, though, that if output prices can't be read straight off of values then neither can input prices, as I indicate above).
Perhaps, rather than use up bandwidth here, it would be appropriate to ask Doug to post Kliman's paper from the Brecht Forum event on the lbo website, from which point I (and others interested) could get a better sense of the "Copernican revolution" he speaks of.
Michael McIntyre
In reply to Michael McIntyre: He wrote: "All Marx did in Vol. III was postulate a set of prices for a commodity and derive value as the mean price. But, of course, you need to run the chain in the opposite direction if you want to show that price depends on value, not vice versa. I won't say that the transformation problem can't be solved, but as far as I know it hasn't been yet ...." I think this description i just p