In response to Paul's discussion of "abstract labor".
I think the "archeological" idea of measuring the labor times required for
certain "productive" tasks in the past is a useful one, though we should
be aware of its limits. For example, in some societies there is no clear
dividing line between "productive" activites and "recreational", or
"ritual" activities.
On the other hand, I think it is unwise to use the technical Marxist terms
"abstract, social labor" for this measurement. I think Marx reserved the
term "abstract" labor for labor expended in a commodity producing society:
what makes it "abstract" is that the product is exchanged for money, not
that it represents some kind of "lowest common denominator" of labor (I
think Marx used the term "simple" labor to represent the reduction of
skilled labor to a common denominator, following Ricardo). Marx reserves
the term "social" labor for labor expended as part of the social division
of labor supported by commodity exchange. Now the labor of the Roman
legions in constructing aqueducts and roads was in a common sense way
"social", but I don't think Marx would have used the term in this way.
"Labor" seems to me pretty general in Marx, for example, in the
Introduction to the Grundrisse, where he uses it in quite a wide sense.
Yours,
Duncan