But the fact that such was the direct and immediate effect of these institutions of ownership in their time by no means involves the instant condemnation of the institutions in question. It is quite possible to argue that slavery and landed wealth, each in its due time and due cultural setting, have served the amelioration of the lot of man and the advance of human culture. What these arguments may be that aim to show the merits of slavery and landed wealth as a means of cultural advance does not concern the present inquiry, neither do the merits of the case in which the arguments are offered. The matter is referred to here to call to mind that any similar theoretical outcome of an analysis of the productivity of "capital goods" need not be admitted to touch the merits of the case in controversy between the socialistic critics of capitalism and the spokesmen of law and order.
The nature of landed wealth, in point of economic theory, especially as regards its productivity, has been sifted with the most jealous precautions and the most tenacious logic during the past century; and any economic student can easily review the course of the argument whereby that line of economic theory has been run to earth. It is only necessary here to shift the point of view slightly to bring the whole argument concerning the rent of land to bear on the present question. Rent is of the nature of a differential gain, resting on a differential advantage in point of productivity of the industry employed upon or about it. This differential advantage attaching to a given parcel of land may be a differential as against another parcel or as against industry applied apart from land. The differential advantage attaching to agricultural land--_e.g._, as against industry at large--rests on certain broad peculiarities of the technological situation. Among them are such peculiarities as these: the human species, or the fraction of it concerned in the case, is numerous, relatively to the extent of its habitat; the methods of getting a living, as hitherto elaborated, the ways and means of life, make use of certain crop-plants and certain domestic animals. Apart from such conditions, taken for granted in arguments concerning agricultural rent, there could manifestly be no differential advantage attaching to land, and no production of rent. With increased command of methods of transportation, the agricultural lands of England, _e.g._, and of Europe at large, declined in value, not because these lands became less fertile, but because an equivalent result could more advantageously be got by a new method. So, again, the flint- and amber-bearing regions that are now Danish and Swedish territory about the waters at the entrance to the Baltic were in the neolithic culture of northern Europe the most favored and valuable lands within that cultural region. But, with the coming of the metals and the relative decline of the amber trade, they began to fall behind in the scale of productivity and preference. So also in later time, with the rise of "industry" and the growth of the technology of communication, urban property has gained, as contrasted with rural property, and land placed in an advantageous position relatively to shipping and railroads has acquired a value and a "productiveness" which could not be claimed for it apart from these modern technological expedients.