Gerard (hello again) writes in response to Alan:
[...]
> You were happy with the first part of my statement: "the basic
> relationships Marx wanted to established are not subject to the
> assumption that commodities are exchanged at their value or at PRICES
> OF PRODUCTION", but not with the second part of it stating that Marx
> "generally assumes' in volume I and II, and even, often in volume III,
> that commodity exchange at their value (what Duncan calls a
> pedagogical assumption).
>
> Let me begin with your assertion: "The alternative reading - that
> Marx did not make this assumption and that his derivation of value
> does not depend on it". I have difficulties with the two parts of this
> statement:
>
> - The first part "Marx did not make this assumption". What do you
> mean? Never? Marx often does this assumption. Sometimes, it is just
> a simplifying assumption. Sometimes, it is rather closely linked to
> the core of its demonstration. Consider, for example, the following
> lines in Volume I, in the chapter "Contradictions in the General
> Formula" (I cite from the Marx Library, p. 261): "It is true that
> commodities may be sold at prices which diverge from their values, but
> this divergence appears as an infringement of the laws governing the
> exchange of commodities. In its pure form, the exchange of
> commodities is an exchange of equivalents, and thus it is not a method
> of increasing value."
But there is a serious problem here. Marx never establishes the
"law" that is supposedly infringed when prices diverge from their
corresponding values [it is certainly not established in section 3 of
Ch. 1, for example], and thus has no grounds for reifing price-value
equivalence as the "pure form" of the exchange of commodities, other
than by reference to certain obscure authorities (Le Trosne?). Thus,
unless this is meant as a mere tautology, there is no basis for
concluding that price-value equivalence is the "pure form" of
commodity exchange.
This problem is serious because it informs what follows:
>There, the exchange of commodities at their
> values is important in Marx's argument since he wants to derive
> exploitation UNDER THE ASSUMPTION of prices proportionnal to values:
Not only does Marx "want" to derive exploitation under the assumption
of prices proportional to values, he *insists* at the conclusion of
ch. 5 that capitalist exploitation must be explained on this basis.
However, this conclusion does not follow from the arguments given in
the chapter. To see this, note where Gerard says:
> exploitation does not follow from a violation of the law of exchange
> (introduced in chapter 2: commodities exchange at their values).
Rather, what Marx has shown is that exploitation does not follow from
violation of price-value equivalence (I hesitate to call it a "law of
exchange" for reasons given above) **taken alone**. This follows
immediately from the definition of surplus value, which requires
the creation of new value, measured by socially necessary abstract
labor time expended in production.
Since exchange is not production, it is obvious that, *taken
alone*, exchange with or without price-value equivalence cannot
create surplus value, *taken alone*. But this virtual tautology cannot
support Marx's subsequent conclusion that surplus value must be based
on the condition of price-value equivalence; for example, the arguments
in the chapter are logically consistent with the claim that capitalist
exploitatation requires "something...in the background which is not
visible in circulation" *plus* price-value disparities, as was in
fact the case for capitalist exploitation via usurer's and merchant's
capital extended to small producers, as repeatedly and explicitly
confirmed by Marx's own historical account.
In sum: in Chapter 5, price-value equivalence is promoted from the
status of an assumption to that of a "law of exchange", and the "pure
form" of commodity exchange. Neither claim is demonstrated, and in
fact any such claim is problematic if not simply invalid. For
example, John Roemer's analysis demonstrates that prices and values
will diverge in general given commodity exchange based on unequal
distribution of wealth. Since Marx does not rule out unequal
distribution of wealth in his Ch. 5 analysis, his elevation of
price-value equivalence is suspect at best.
Moreover, his methodological stipulation, to the effect that surplus
value must be explained on the basis of price-value equivalence,
simply does not follow from the arguments given in Ch. 5.
Gil Skillman