If we should assume for the moment that there were exact units of disutility and skill as of time, Adam Smith’s theory would signify that the quantity of labor in any particular case is measured by time units weighted with units of disutility and of skill. The amount of two different kinds of labor commanded in exchange by any commodity depends upon the wages commonly earned at these kinds of labor. If a certain commodity, worth such and such a sum of money, commands in exchange one day of labor in employment A and two days in employment B, Adam Smith would be forced to assume that one day of A is the same quantity of labor as two days of B. At bottom, then, the theory means that one day of A is the same quantity of labor as two days of B, because these two pieces of labor get the same wages. Taking it for granted that the amount of wages paid (under competitive conditions) is a true test of the _quantity_ of labor in any given concrete task, we shall find some further speculation on this question if we turn to the famous chapter upon the inequality of wages in different employments.[24] In this chapter there is a suggestion that the extra reward for skilled labor is a disguised payment for superior disutility. The following analogy drawn between skill and a machine has been used by many later writers: “When any expensive machine is erected, the extraordinary work to be performed by it before it is worn out, it must be expected, will replace the capital laid out upon it, with at least the ordinary profits. A man educated at the expense of much labour and time to any of those employments which require extraordinary dexterity and skill, may be compared to one of those expensive machines. The work which he learns to perform, it must be expected, over and above the usual wages of common labour, will replace to him the whole expense of his education, with at least the ordinary profits of an equally valuable capital.... The difference between the wages of skilled labour and those of common labour is founded upon this principle.”[25] Thus skill represents disutility incurred in its acquisition, and the surplus reward to skill is virtually reward to disutility in a form bearing analogies to interest. This is for acquired skill. What is to be said of inborn skill, of native superior talents? This question apparently escapes Adam Smith. Uniformly, the tacit assumption underlying his thought seems to be that of the inborn equality of powers in men. Keeping this assumption in mind, we see that Smith’s view amounts to the theory that all occupations are about equally well rewarded, all things considered. Higher wages are paid only where there is more labor, ultimately in the sense of _disutility_. The _inequalities_ of wages are such only in proportion to the _time_ of labor.[26]