To give a mid-chapter summary of results—put together by ourselves rather than by Smith—if the exchange values of goods are to be governed by the quantity of labor which they have cost, and the “real worth” of goods is to be measured either by the quantity of labor they have cost or by that which they can command in exchange, there must be some means of defining the _quantity_ of labor in different employments. Adam Smith has made this depend, in the first instance, upon time compounded with amounts of disutility and skill. But he has further suggested that the element of skill really represents a past disutility. The principal assumption involved is that all occupations are competed for by men born equal in efficiency. If he did not clearly avoid the appearance of laying down hard and fast principles, we could conclude that he meant _quantity of disutility_ by quantity of labor. 5. The dictum that labor is the means of measuring the “real worth” of goods does not, I believe, necessarily involve the notion that this measure can be used to compare the value of a good in A.D. 1400 with its value in 1800, or its value in China with that in England. An important part of the chapter on the real and nominal price of commodities is given over to the claim that labor furnishes an “invariable measure” of value in all times and places. Money, the most convenient measure of value in a given time and place, varies in its value in different times and places. But “Equal quantities of labour, at all times and places, may be said to be of equal value to the labourer. In his ordinary state of health, strength and spirits, in the ordinary degree of his skill and dexterity, he must always lay down the same portion of his ease, his liberty, and his happiness. The price which he pays must always be the same, whatever may be the quantity of goods which he receives in return for it.... Labour alone, therefore, never varying in its own value, is alone the ultimate and real standard by which the value of all commodities can at all times and places be estimated and compared.”[27] In this passage the misuse of the word value is flagrant, but the meaning is plain. No matter what be the physical quantity of goods which a day of labor either produces or earns as wages, the value of these goods, in the sense of _significance_ to human welfare, is the same, _because_ they cost the same amount of disutility. The person who purchases labor commands it sometimes with a greater and sometimes with a lesser amount of goods: “It appears to him dear in the one case, and cheap in the other. In reality, however, it is the goods which are cheap in the one case and dear in the other.”[28]