There's a problem here with the term "prediction".
Jerry, you're taking it to mean "telling ahead of time", which indeed
it literally means. Yet in the sense in which Paul is using the term
-- which is fairly widespread in the philosophy of science -- no
particular temporal order is implied. Etymologically, "prediction"
and "forecasting" ought to be pretty much synonymous, but in the
philosophy of science the act of telling ahead of time is labeled
"forecasting", while "prediction" is given a more generalized meaning.
This may seem like semantic legerdemain, but there is a basis for it.
Consider Newtonian mechanics, as applied to the celestial sphere.
Did Newton really latch onto something, with his account of how
physical bodies interact via gravitation? An affirmative answer seems
to be validated by the ability of the Newtonian theory to predict the
existence of unknown planets, such as Pluto. Given the existing
observations on planetary motions, the Newtonian theory suggests that
those observations are best explained by postulating the existence of
a new planet at (roughly) such and such a location. We look
carefully, and -- Wow! -- there is a planet there. Since the theory
was initially constructed with no such data and questions in mind,
this is very impressive.
Yet the question of temporal order is secondary. Consider another
well known celestial example: the "predictions" of Einstein's theory
of Relativity with respect to the perihelion of Mercury. The problem
was that the orbit of Mercury around the sun exhibited some peculiar
features that were not readily explicable on the Newtonian theory.
To account for the observed orbit, a Newtonian would have to postulate
some unobserved planet that was mucking things up. In itself that
hypothesis was not unreasonable. After all, Mercury (being so close
to the sun) is hard enough to see, and another planet even closer to
the sun would be very tricky to spot. But it was never spotted. The
sole reason for believing in the existence of such a planet was the
Newtonian theory.
Along comes Einstein and says, "Hey, this orbit for Mercury is just
what my theory predicts!" (with no unobserved planet). Of course, he
wasn't actually _predicting_, in the sense of forecasting, since the
facts about Mercury's orbit were well known already. But his theory
"produced the phenomena" in a way that Newton's did not. In
principle, one might worry that Einstein had "cooked up" his theory
precisely to "account for" the previously known facts about Mercury's
orbit. Yet any physicist who examined Einstein's theory would
immediately see this worry was unfounded. Einstein's theory was an
very general one, lacking "free parameters" that could be
surreptitiously tuned to match the perihelion of Mercury. The
"prediction" was highly impressive, even if it was after the event; no
less striking a confirmation of the fact that the theorist was "onto
something" than the Newtonian prediction of unknown planets.
What's the relevance to Marxism? Paul is arguing (and I agree) that
the labour theory of value is a predictive theory in the extended
sense. It can "produce the phenomena" (not necessarily ahead of time)
in a way that (e.g.) Value Form theory cannot. Paul also argues (and
again I agree) that this sort of predictive theory is needed to
validate (or even make sense of) key points of Marxist theory, such as
the theory of relative surplus value.
The idea of relative surplus value is that capitalists pursue an
increase in surplus value by reducing the labour content of the
workers' means of subsistence. This idea is open to the immediate
objection that capitalists are not really interested in surplus value
at all; they're interested in profits. Profits are increased by
cutting costs or raising sales revenue: who is to say that this effect
is produced by reducing the labour time needed to produce the workers'
consumption goods? "In general", without recourse to the labour
theory of value, there's no reason to believe that increased profits
have anything to do with increased exploitation, in the sense of the
workers' working a shorter time for their own benefit and a longer
time in the production of a surplus product. But the labour theory of
value tells us ("predicts") that to achieve an economy-wide reduction
in the cost of the workers' means of subsistence, a necessary and
sufficient condition is that the labour time needed to produce those
means of subsistence be reduced.
Allin.
This archive was generated by hypermail 2b30 : Sat Jun 02 2001 - 00:00:07 EDT