I agree with Gil about the difference between equivalence and equality. If
what Marx and Aristotle meant was that in order for two commodities to
exchange,that there must be some homogeneous element common to both, then
they are both wrong. The fact that Marx defines, as a primitive, a
commodity to be a thing produced by labor for exchange (so that all
commodities thereby contain labor), does not warrant the logical move that
exchange requires that a common element, and in particular labor, is
contained in each commodity.
Would it be possible to imagine conditions for exchange based on something
other than a common element? Sure. How about desire....which leads you into
the whole tradition of neoclassical economics. There is no condition of
equality of a common element in utility based theories of exchange.
Putting Gil's point slightly differently, I think, all that is required for
exchange is the juridical right to alienate one's product in exchange for
anotherr. That is, sufficient property rights need to be in place. On
this point see the first three chapters of Culter, Hindess, Hirst and
Hussain in _Marx's Capital and Capitalism Today_, volume I, 1978.
I suspect that the fact Marx elaborated his theory of surplus value based
on a theory of value where exchange was posited as an equality, had more to
do with the prevalence of the "substance theories of value" at that time,
rather than any deep-seated insight into what "exchange really is" or the
fact that exchange must be conceived this way in order to define the
concept of exploitation coherently (which is evidently incorrect).
Steve Cullenberg
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Stephen Cullenberg tel: (909) 787-5037 x1573
Department of Economics fax: (909) 787-5685
University of California scullen@ucrac1.ucr.edu
Riverside, CA 92521