wheat land also doubled, there is no reason to doubt that the value of that invention would also be doubled; that is, it would add two dollars to the productivity of twice as many people as before. Something like this has probably taken place since the twine binder was invented. But suppose the population had doubled without any increase whatever in the available wheat land. Would that invention still have been capable of adding two dollars to the product of every person, or only a dollar and a half? Or, let the population go on doubling and quadrupling generation after generation, without any increase in the available wheat land, would the twine binder continue indefinitely increasing every person's productivity by two dollars, or only one dollar, a half dollar, etc.? If there is no more wheat land to gather harvests from, is it certain that any more twine binders would be needed with a dense than with a sparse population, or that the value of the invention would increase at all? Has not Professor Norton erred in thinking of labor as the sole factor of production, omitting to think of land as even furnishing a necessary condition of efficient production?
Let us present the argument in another form. An agricultural invention might easily reduce by two dollars the cost of cultivating every acre of land under tillage, thus increasing the efficiency of labor. Obviously then, other things being equal, the more acres there are under tillage the greater will be the total saving effected by the invention. If labor and capital increase in proportion as the land under tillage increases, there is no reason to doubt that the total saving would increase in exact proportion as the land under tillage increased; that is, it would continue to amount to two dollars multiplied by the number of acres. But suppose the labor and capital to remain stationary, while more and more land is brought under tillage, would the saving continue to be two dollars per acre, or would it fall lower and lower? This illustration is given merely to show the necessity of considering all the factors in a problem of this kind, and not a part only.
So long as there are new acres of land being made available, and new funds of capital coming into being, all the results which Professor Norton posits may actually happen. But what does it signify to say that a large population using large areas of land may be quite as well off as a small population using small areas of land, and that an increasing population may be better and better off provided it not only has more and more land but is improving the arts of production at the same time? This, it will be observed, is quite different from saying that we "arrive at the conclusion that the comfort and prosperity of a population tends to increase more rapidly than the population upon which it depends." Until it is shown that this is true, however small the area of land or the supply of capital, it is no refutation of the Malthusian theory, and it is not even a criticism of the law of diminishing returns.
