The exchange value of a good varies inversely with the supply of it presented to the body of consumers. The larger the supply, the lower is the price equivalent which must be reached as the marginal determining point of its market price.[267] A change of supply alters exchange value only because it changes the marginal price equivalent.[268] In the social market, the purchasing powers of all the various products over one another depends upon their relative supplies. So far as cost of production in any form exercises any degree of control over the value of a good, it can act solely by way of influencing the supply of the good. The phenomenon of the apparent regulation of the exchange values of products by their entrepreneur’s costs, is but a part of a large process in which cognate (or “fellow”) products adjust their relative supplies and their exchange values to one another, to the end that the common production goods entering into all of them may produce equal productive contributions or shares of exchange value per unit in all of their productive applications.[269] The relation of the pain costs of products to their exchange values is limited to one of mere proportionality.[270] The pain cost of a product may be calculated in two very distinct ways, giving total pain cost or marginal pain cost. The total pain cost of a good, consisting in all the labor and abstinence ever endured to bring it into existence, is quite an indeterminate quantity,[271] and its influence upon the exchange value of a good is very remote and irregular. The larger part of total labor cost, the part which includes the labor directly applied to commodities, plus the labor indirectly applied by being directly applied to the raw material and machinery immediately used in their production, and so on for the few nearest generations of machines, this being the part which excludes the infinitesimal bits of labor cost expended far in the past, can be shown positively not to be in proportion to their exchange values. For commodities produced at a higher expense of rents of all kinds (as opposed to wages) have exchange values out of proportion to this calculable part of their total costs.[272] We find that the control of _marginal_ cost over value is closer than that of total cost. If it were not for the existence of innumerable grades and classes of skilled labor, the supplies of produced goods would be so adjusted that their exchange values would be in proportion to their respective marginal costs. But on account of skill, we must here again characterize the influence of subjective cost as remote and irregular.