The view that cost is the essence of value is thus obviously irrational, and no escape from this difficulty is afforded by the concession made explicitly by Ricardo, and after him by Marx, that utility is a _condition_ prerequisite to value. The problem of directing labor in production is a question of _how much_ labor can be economically employed in making such and such a useful thing. In the theories of Ricardo and Marx, the _quantity_ of value is held to have no relation to the _quantity_ of utility, but to be determined by the quantity of cost. There must be a quantity of utility to which the quantity of productive power destroyed in its obtainment is adjusted. Utility properly conceived, there is such a quantity, and value is its measure. 3. In the first general argument for the labor-command standard, Adam Smith seems to regard labor solely in the aspect of productive power; but, as the reader will recall, we do not advance far in his many-sided discussion before we encounter labor as _disutility_. Labor is later said to be an “invariable measure,” because it stands for a constant amount of hardship. Beyond a doubt, _disutility_ is associated with value (as “_Bedeutung_”) in some very intimate relation.[40] This is, at bottom, the explanation of the remarkable vitality of the labor theory, even in forms that are absurdly incorrect. If it is my labor which is commanded in exchange by a given commodity, the personal value to me of this commodity for which I have given my labor might well be carried in my mind in terms of the disutility it cost me. So, in a general way, if the amount of some kind of commodity which can be bought by a day’s wages (_i. e._, which “commands” a day’s labor) alters, the significance of this commodity to wage-earners in general will alter. Some persons might conceive the change in significance chiefly in terms of altered disutility cost. This fact is probably considered by statisticians when they investigate questions of real wages, or changes in family budgets. But Adam Smith’s proposition that labor commanded in exchange is a precise and invariable measure of “_exchangeable_ value” is not a good form of stating so mild a principle.