In accounting for the value of consumption goods the Austrian theory takes their supply for granted. In the same way, when the Austrians come to their explanation of the law of cost they take the supplies of production goods for granted. If the supply of pig iron brought every year to the iron market be increased, the supply of the products of iron will be increased and the exchange values of these products will fall. The exchange value of pig iron will fall in consequence.[232] At this point a question—a criticism in behalf of the cost theories of value—naturally suggests itself. Is not supply ultimately regulated by cost of production in some form, and is not cost of production thus either the ultimate regulator of value itself, or at least a joint regulator with utility? We have suggested here the famous question of the “reconciliation” of the cost and the utility theories of value. It is certain that the only form of cost which can exercise ultimate control over the supply of any produced good is what we have called by the generic name of “pain cost.” The potentiality cost of a product is measured in the value of the production goods entering it. But this value itself depends on the supply of these production goods. The ultimate cost regulator of the value of both the products and the production goods cannot be potentiality cost. The influence of potentiality cost causes the supply of the individual kind of product merely to be adjusted to the supplies of its cognate products. But potentiality cost has no influence whatever over the total supply of the production goods or the absolute supply of the total mass of cognate products. To appeal to a simple illustration, if a flow or stream of some production good be supposed to divide into several branches as it proceeds, each branch representing one of the several cognate products of that good, the influence of potentiality cost may determine the _relative volumes of the different product-streams_, but only pain cost—if any cost at all—can influence the volume of the parent stream, and thus govern the _absolute volume of all the branches_. Entrepreneur’s cost also, most obviously, fails as an ultimate regulator of supply. This cost is but the proximate agency through which the two elementary forms of cost exert their influences upon the relative and absolute supplies of products. Undoubtedly the recognition that pain cost is the only form of cost capable of exerting any ultimate control of value, helps to suggest that it be called “real cost” or “true cost.” Professor Marshall, for instance, analyzes cost into two forms, (1) real, and (2) money costs.