and consequently the values, of cognate products are being adjusted to one another. The whole truth is that the value of production goods is determined by the value of their products. Because of the existence of great common production goods of manifold productive uses, we have the peculiar reaction of the value of production goods on the value of products, a part of which process is described in the law of entrepreneur’s cost. The case of real life is more complex than the one considered above in that a plurality of common production goods always enters into a product. In this more complex case we find an entirely new problem, which rejoices in the name of the “imputation of the productive contribution,” but the explanation of the law of entrepreneur’s cost remains exactly the same in principle as that given for the artificially simplified case. When a product is made from several production goods, as a carriage from wood, iron, leather and labor, the value which by anticipation the production goods derive from the product is divided among them. The share of value of each production good is called its productive contribution. The different solutions of the problem of imputing the productive contribution already offered in the literature of value and distribution, will not be discussed here.[228] One principle, however, will be taken for granted. It will be assumed that the productive contribution of any kind of production good in the value of a particular kind of product varies inversely with the supply of this production good which is turned to the making of that kind of product. If product A is made from production goods P, Q and R, and the amount of P used in producing A’s is increased—with or without an increase in the amount of Q’s and R’s used[229]—the productive contribution of a unit of P in the value of A’s will be decreased.