The question has come up again recently (under the rubric of 'Lenin as
non-dualist'), as to whether Marx's theory of value is (at least in part)
a theory of relative prices, or whether it should be understood at a
purely aggregative level. I have a 'history of thought' point to make on
the matter.
Marx wrote voluminously on his predecessors, Smith and Ricardo in
particular. He made several specific criticisms of Ricardo (not always
with justice), and he had one 'large' criticism, namely that Ricardo
failed to investigate the origins or preconditions of commodity
production, that he treated the expression of socially necessary
labour-time in the prices of commodities as something 'natural', rather
than seeing the production of commodities as a historically specific
phenomenon. This (obviously important) point aside, it is noteworthy that
Marx is nonetheless full of admiration for Ricardo's scientific acumen,
and that the key index of this acumen, from Marx's point of view, is
Ricardo's rigorous and consistent (as compared with Smith) adherence to
the labour theory of value.
It seems to me that this judgment on Marx's part -- often repeated and
clearly integral to his thought -- becomes entirely unintelligible if one
follows the 'revisionist' practice of driving a wedge between the two, and
insisting that Marx had no interest in relative prices. Yes, of course
Marx realized that the exchange values of commodities are not exactly in
proportion to their labour-content; and of course Ricardo realized this
too. Yet Ricardo held that deviations of exchange-value from value were
mostly accidental (and relatively minor). Even where the deviations were
systematic (he realized perfectly clearly that the equalization of profit
rates contradicted the simple labour theory of value), Ricardo held that
this was a second-order effect -- this is, BTW, an important difference
between David Ricardo and the neo-Ricardians. If Marx believed that
Ricardo had been wrong on this, we can be sure he would have said so; but
he never did. Not once does he disparage Ricardo for holding to what has
been called the 'labour theory of value' for the last century or so; on
the contrary, this is always grounds for praise.
I think we are entitled to infer: that Marx saw Ricardo's theory of value
as _inadequate_ (since it did not address the specificity of commodity
production); but also that he saw it as substantially correct _so far as
it went_ (which was a long way).
I suspect that the tendency of Marxists (since the 1970s) to discount the
commonality between Marx and Ricardo is an effect of the rise of
neo-Ricardianism, and in particular the 'turn against Marx' taken by some
neo-Ricardians (mostly notably Ian Steedman). But the historical Karl
Marx and the historical David Ricardo were both proponents of a labour
theory of value (understood as, inter alia, a theory of relative prices)
that is rejected (offensively) by certain neo-Ricardians and
(defensively?) by certain Marxists.
Allin Cottrell