This makes it appear as though all wealth were split up into "atoms," but it is so only in appliance; as a matter of fact within the sphere of the marginal law every "atom" in the whole circle of wealth is valued by this method of measurement; not only are all the marginal employments put in evidence but, with and though them, all permissible employments from the highest down to those standing on the margin, -- only that we are saved the trouble of putting into the calculation any but the marginal uses. This makes it possible to calculate even the almost infinite quantities which are destined to meet almost infinitely various wants. For the purposes of carrying on ordinary private business, for instance, the whole enormous agricultural wealth of a nation can be quite properly grasped through the ordinary economic estimate of the same, even although this estimate, which only takes stocks and marginal employments into consideration, is very far from giving expression to the whole importance which those satisfactions that are provided through agriculture have for the life of the nation. There is, therefore, nothing more misleading than to introduce a treatise on the price of agricultural products by a disquisition upon the importance of agriculture in this latter sense. The "surplus value" left out from the calculation need not be taken into the calculation; for one thing, that it is omitted, not only in agricultural taxation, but everywhere, and, for another thing, that, as regards detail, a quite adequate balancing of agriculture against trade, industry, and the other branches of economy, and also of the individual businesses of agriculture against each other, may be obtained, if only the margin be everywhere observed down to which wants are satisfied, production extended, and cost goods expended.
If this same agricultural wealth be considered with regard to the purposes of general economic politics, the point of view changes. We are no longer concerned with innumerable individual goods as opposed to each other, but with that which affects them all in common. Thus agriculture, or great parts of it, become a whole; then is the time to consider the importance of all its services; and then we have to face an enormous complex of results which must all be estimated in their entire extent.
Second: by private economy the whole productive return --again taking into account the smallest quantities -- is distributed among the complementary productive factors without remainder. The sum of all the "productive contributions" is equal in value to the total return, and the productive value is consequently as clearly calculable as the value of the products.
On the other hand, in questions of economic politics, if the destinies of large quantities of production goods have to be weighed all at one time, the estimate of the "contribution" does not suffice. It becomes necessary to undertake the exceedingly difficult task of considering how deep the "complementarity" of the productive factors in its ultimate ground may reach, and how far these factors mutually condition one another -- in the way of fructifying or serving as foundation -- if they are all at once brought together in masses, or severed from each other. Here, again, in the "contribution" of private economy we calculate only the marginal value, whereas, in the total "co-operation" of national economy, we calculate the more far-reaching and less easily calculable importance of the goods.
This must all be understood with the above-mentioned limitation, that we have here indicated only the leading characteristic of the two economic systems, while each system always shows traces of the other, and the transitions from one to the other escape notice.
