510 THE POPULAR SCIENCE MONTHLY 
PROFESSOR NORTON’S LAW OF PROGRESS 
By Proressor T. N. CARVER 
HARVARD UNIVERSITY 
ROFESSOR J. PEASE NORTON’S recent article on “The 
Cause of Social Progress and of the Rate of Interest ” contains 
a notable contribution to economic theory. His analysis of the way 
in which other factors contribute to the value of the work of the genius 
is most acute, and his reasoning is, up to a certain point, entirely sound. 
It is, however, merely a part of the universal law of diminishing re- 
turns, and not, as he seems to think, a refutation of that law. Of two 
factors, X and Y, combined for the production of a given result, if one 
factor, Y, increases, that increase adds, within limits, to the effective- 
ness of each unit of X, but correspondingly detracts from the effective- 
ness of each unit of Y. If, for example, one man, cultivating ten acres 
of corn, can produce a thousand bushels, he can, ordinarily, if given 
twenty acres of the same kind of land, produce more than a thousand 
bushels, say sixteen hundred bushels. Give him the use of still another 
ten acres, making thirty acres in all, and he can produce still more corn, 
say two thousand bushels, and so on, until a point is reached when 
additional land would be of no use at all to him. Up to this point, 
while every added increment of land adds to the crop produced per unit 
of labor, at the same time it reduces the crop produced per acre of land. 
This is a case similar in certain respects to that assumed by Professor 
Norton, of a genius who makes a labor-saving invention by means of 
which there is an increase of two dollars per capita in the product of 
the community. The larger the population the greater the product of 
this man’s labor, or, which amounts to the same thing, the greater the 
value of the invention. Professor Norton assumes, however, that the 
product, or the value, of this invention would increase in exact ratio 
with the population. This he has no right to assume. In fact, imas- 
much as the universal opinion of economists is to the contrary, he is 
under some obligation to support his assumption by definite and posi- 
tive proofs. It is probably true, at least some economists would agree, 
that if the population and the land and natural resources, and the 
capital as well, all increase with the population, this joint increase of 
all productive agents would bring an exactly proportionate increase to 
the value of the invention. But if the population alone increases, while 
the land and capital remain fixed in quantity, then the value of the 
invention, while it may increase, will certainly not increase as fast as 
the population increases. The twine binder, for example, undoubtedly 
increased the productive power of labor. Let us assume that at the 
time of its invention it added two dollars to the product of every person 
in the civilized world. If the population doubled and the available 
