> Alan wrote in [OPE-L:4557]:
>
> > The initial question was: can labour from different time-
> > periods (vintages) add different amounts of value?
Jerry in #4559:
> Yes. What is understood as socially necessary labour time can
> change over time [and regionally and internationally].
What do you understand as "snlt"?
Of course snlt can change.
In 1996 to produce 1 coat is needed 1 hour and, in 1997, only 1/2
hour.
In both years 1 hour objectified 1 hour of labor-value, so that the
fall in snlt does not mean that 1 hour in 1997 corresponds to 2 hours
of 1996.
In 1996 are produced (and sold) 2 coats. This means that total
production in coat branch amounts to (1hour/coat)*2 coats = 2 hours
of labor-value.
In 1997 the demand remains the same and then 2 coats are produced.
Total labor-value is (1/2hour/coat)*2coats = 1 hour. Thus, total
labor-value objectified in this branch falls from 2 hours (1996) to 1
hour (1997).
If the MEL is the same in both periods ($1 = 1 hour), in 1996 coat
branch realized $2 and in 1997 only $1. It is clear that while
"material wealth" has remained constant (2 coats) "social wealth",
"value" falls from $2 to $1.
If I interpret correctly what Duncan says, the calculation is as
follows. In 1997 the productivity of coat labor has increased and
then the 1/2 hour used in this year should be weighted by the ratio
between both productivities, i.e. (2/1) = 2.
This means that 1 hour used in 1997 to produced 2 coats, "actually"
corresponds to 2 hours of "weighted labor-value". Social wealth
(value) doesnt fall, despite the increasing productivity. In both
years, coat industry realizes $2.
Alejandro Ramos