“the sacrifice will be measured by the quantity of wealth abstained from, taken in connection with the risk incurred, and multiplied by the duration of the abstinence.”[177] With this much said, Cairnes drops risk from consideration. We may follow his example in the present chapter, since the precise relation of risk or risk-taking to cost of production need not be decided in order to determine the import of Cairnes’s work for the labor theory. 2. In Cairnes we find a repetition of the protest of Senior against the definition of cost from the point of view of the capitalist-entrepreneur. Thus Cairnes is “compelled to dissent” from the “radically unsound” doctrine of Mill, that wages and profits compose cost of production. “Of all ideas within the range of economic speculation, the two most profoundly opposed to each other are cost and the reward of cost.... Cost and remuneration are economic antitheses of each other.... Now in the analysis of cost of production which I have quoted [_i. e._ Mill’s] these two opposites are identified.”[178] Cost cannot be defined from “the partial and limited standpoint of the capitalist-employer.”[179] Cairnes makes an excellent and eloquent plea for his idea, but truly all that can be conceded to him is that the two kinds of cost must be scrupulously distinguished, and that propositions true only of disutility costs must not be affirmed of entrepreneur’s costs, and _vice versâ_. As for the views of Mill, this economist stated that wages and interest are rewards as well as costs. The gross inconsistencies, however, of Mill’s language in different parts of his book justify scathing criticism. 3. Cairnes does not quit the subject of the measurement of the subjective cost without turning his attention to an incidental problem not touched, I believe, by his predecessors. He states that the effort required to produce a given result does not represent the same sacrifice for different persons, being one thing for the strong or experienced and another for the weak or untrained. Similarly a given sum of capital may stand for no appreciable self-denial on the part of the person contributing it, if he be rich, but for very rigid self-denial if he be poor or in moderate circumstances. How are such differences, Cairnes asks, to be dealt with in computing the cost of production? “The sacrifices to be taken account of, and which govern exchange value, are, not those undergone by A, B, or C, but the average sacrifices undergone by the class of labourers or capitalists to which the producers of the commodity belong.”[180]