The chief purport of the work of Malthus was, first, to deny Ricardo’s right to disregard the interest difficulty and, second, to reaffirm Adam Smith’s opinion that land rent also throws values out of relation to labor costs. Turning now to Senior, who was the next writer to suggest a worthy and new idea, we find that in the view of this economist the existence of land rent and interest as elements in entrepreneur’s cost is fatal to the labor theory. But Senior explained interest as the reward for abstinence, just as wages are the reward for labor. In his view labor and abstinence are independent, co-ordinate elements in subjective cost.[202] However, the more important idea that can be extracted from Senior’s reasonings is that wages as actually paid are not in proportion to the quantities of labor engaged in different employments. For in his view all skilled labor gains a wage which really includes a rent to “scarce natural talents.”[203] Summing up the results of Senior’s argument for ourselves (since he himself did not make the present applications of his doctrines), the labor theory requires that the entrepreneur’s costs of commodities should be in proportion to their labor costs, but entrepreneur’s costs are out of proportion to labor costs, not only because they include rent of land and interest on capital, but because the very payments of wages themselves may be out of proportion to the comparative amounts of labor employed and remunerated. When we say that entrepreneur’s costs are out of proportion to labor costs, we do not mean that they are in excess of wages cost, though they are this, but that for commodity A to cost the same quantity of labor as commodity B, is not a sign that the two commodities have the same entrepreneur’s costs. In other words, relative entrepreneur’s costs are not determined by relative labor costs. John Stuart Mill took Ricardo’s view of land rent and of interest, but took Senior’s view that skilled labor occasions the entrepreneur an expense out of proportion to the _quantity of labor_ remunerated. That is to say, he held that the higher wages of skill do not represent a higher labor cost. This opinion he adopted without at the same time taking up Senior’s particular use of the term, “rent to talents.” As we concluded at the end of Chapter IX, it may be said that Mill followed Ricardo more closely than any other of his predecessors on the question of the relation of labor to value. Turning to Cairnes we note that this writer gave one sentence in his book to the doctrine of land rent, and in this he acquiesced in the judgment of Ricardo and J. S. Mill. But Cairnes adopted a position with reference to interest identical with that assumed by Senior, and his theory of “non-competing groups” merely emphasizes the claim that the amount of wages paid in different employments is not a test of the quantities of labor employed.