Читать книгу Essentials of Economic Theory - John Bates Clark - Страница 15

[1] For extended discussions of the relations of utility and value the reader is referred to the works of Jevons, Menger, Von Wieser, Von Böhm-Bawerk, and Walras. A study of "effective" utility and its relations to value, by the writer of the present treatise, is contained in the New Englander for July, 1881.

[2] If we should try to describe all the possibilities in the case, we should take account of the fact that a man may get a positive pleasure from his first hour or two of labor and construct a figure thus to express this fact:—

AC is the curve representing the sacrifice entailed by successive hours of labor.

In like manner we should have to recognize the fact that the utility of some kinds of goods may not reach a maximum with the first increment, and should construct a utility curve to express this fact. BC here represents the increase and the following decrease in the specific utility of the supply of an article of this kind.

[3] The terms marginal and final mean essentially the same thing, but the modes of conceiving it differ. When utilities are thought of as supplied one after another, the last is the least important. We may represent a man's enlarging gratifications, not by such a mere series of quantitative increments, but by an enlarging area. We may draw a series of concentric circles, beginning with the smallest, and let this central area inclose the most necessary forms of consumers' wealth. When we draw a second and larger circle, we inclose between it and the first one a zone which includes those forms which come next in importance. By continuing to draw circles we reach an outermost one which bounds a zone in which are included the least important of the consumer's acquisitions. These are the things which he gets with his costliest increment of labor, and the things which lie beyond the circle last drawn would not pay for the sacrifice which acquiring them would cost. In the accompanying figure the fifth zone includes these "marginal" forms of wealth.

[4] Although we may use the terms final utility and effective utility in a way that makes them nearly interchangeable, it is clear that the qualities for which the two terms stand are by no means identical, and that effective utility must be studied in any complete analysis of value. In distinguishing final utility we assume that the units of the supply of goods of a particular kind are furnished one by one, and we measure the absolute utility of each unit. The line AB measures the absolute utility of the first unit supplied. This measurement does not take any account of the cost of replacing this unit, for it does not recognize the possibility of replacing it. What is estimated is the absolute importance of the service which this first unit of the article renders, on the supposition that, if this first increment of the supply were wanting, the service would not be rendered at all. It is, in like manner, the absolute utility of the successive increments supplied which declines along the curve BC. DC measures the absolute utility of the final increment, and the area ABCD the total absolute utility of the supply. If the goods can be reproduced by labor, the total effective utility is less, since it is measured, as we have seen, by the amount of sacrifice which the replacing of one lost unit would entail multiplied by the number of units in the supply. It is the amount expressed by the area AECD which is the amount of the value of the goods, since measure of effective utility and value are the same, both in the case of a single unit and in that of a total supply.

We have discovered two reasons why the effective utility of any one of the earlier units is equal to the absolute utility of the final one. The first reason is that, if any one of them were lost, the final one would be put in the place of it and the consumer would suffer no loss except what would be entailed by going without the last unit. The second reason is that if the consumer should lose any one of the earlier units, he could replace it by the same amount of labor that would replace the final one. We have seen that the line DC of the figure expresses not only the absolute utility of the final unit of goods, but the disutility of the labor of reproducing it or of reproducing any other unit. The cost of replacing the whole supply is expressed by the area AECD, on the supposition that the units are replaced, one at a time, by means of labor performed at the end of several working days when the sacrifice is greatest. Total value is thus quantitatively equivalent to total effective sacrifice of replacement, as well as to total effective utility. If, by adding a brief period to the length of one working day, a man can make good the loss of one unit of the goods, by adding the same period to the length of a number of working days, he can make good the loss of the total supply. For simplicity we assume that the man's physical condition remains unchanged, and that an extra hour of labor at the end of any one day costs him as much as it would at the end of any other.

[5] The law of diminishing returns of successive units of capital goods is based on the same principle as the law of diminishing returns of capital, but it is not identical with it. We shall see, in due time, how a permanent fund of producers' wealth actually grows and why each new unit, as it adds itself to the fund, creates a smaller income than did its predecessor.