A followup comment in my exchange with Paul C. concerning the
connection between equivalence and equality. The source of the
logical difficulty I see in his argument is expressed in the
following passage from his previous post:
> The question becomes what is the relevant axiom set. In
> discussing equivalences between commodities, properties such as
> weight are clearly irrelevant. The only thing that is relevant
> is what they will exchange for, in these terms the elements of
> the set induced by ~e are equal to one another. So the
> equivalence relation is an equality relation.
The claim that "[t]he only thing that is relevant is what they will
exchange for" assumes exactly what must be proven, and is at best
problematic, as the counter-example involving uncultivated land (or
any other exchangeable which is not a product of labor) illustrates.
In solidarity, Gil Skillman