This man wants to make the sun worth something." *

II. A NORMAL VALUE OR AN EXCHANGE THEORY OF WAGES.
With the data in hand we might readily construct
an abstinence theory of wages that would be identical
in all respects with the abstinence theory of interest.
This, however, would give us, in the one case as in
the other, but a partial solution for the problem. We
are here dealing with a mobile, homogeneous fund,
or with normal value ; hence disutility and utility, or
abstinence and productivity, must be equated. The
marginal saver will not endure the disutility of ab-
stinence unless he receives a corresponding surplus
in his future product. It follows from this that any
satisfactory solution of the wages problem must take
account of productivity as well as of abstinence.
While special laborers may receive more or less than
normal wages, all labor that is free to move must re-
ceive at least normal wages. How much this will be
is determined by the product of such free labor in the
least productive branch of the whole field of indus-
try ; in other words, by the marginal productivity of
labor. This raises the question. How is tliis margin
or the supply of labor determined ? The answer is as
follows : The increase in the amount or efficiency of
labor depends, in the first instance, on the realization

* Annals of American Academy, July, 1892, p. 41.
