THE PROBLEM OF WAGES 123

represented by more than a single individual, In such a
unit, there is nothing to hinder regarding, say, two efficient
men as the equivalent of three less able ones, if their net
product is equal to that of the three. The equivalence of
units that is of real importance, in reference to the points
discussed, is an equivalence of producing power rather than
of individuals. If wages correspond to work done, all that
has been said may be applied with this modification. If
wages are equal per man, then a modification must be
introduced, since the more productive individuals will
represent a greater net product to the employer than those
less capable, and thus marginal productivity per man may
fall off more rapidly than if the men were really of equal
working power, since the more able will be preferred, and
therefore, additions to numbers will generally be of less able
units, and reduction of staff will take place by weeding out
the less efficient, Thus, in the long run, even if wages per
man are paid at a uniform rate, while the men are of unequal
ability, opportunity to earn those wages will be more
continuously afforded to the more able than to the less able,
even if a difference of actual payment is not effected, eg. by
a change in the designation of the task of the more capable,
accompanied by a change in payment. In spite, then, of
actual differences between human capacities, the correspondence
 of the marginal net productivity of labour with the
demand-price may be maintained. The units of human
productive energy are interchangeable over a much wider
field than persons are capable of substitution one for another,
and individual workmen may be regarded as representing
a greater or smaller number of such units of productive
energy.
When we have to deal with exceptional kinds of work,
for which the available men capable of performing the work
are few, the device, for determining the individual contribution
 to the total product, to which recourse has been
had above, is no longer necessary. The work of the individual
 being able to be more directly associated with its
result, we are not met with any great difficulty in answering
the question: What is the net product of a man’s work? It