Marginal Utility Even where nature is most lavish with her gifts, there are but few kinds of goods with which she provides man in such superfluity that he can satisfy every, even the most insignificant, sensation of want. As a rule the supply of goods of which he can avail himself is so scanty that he must break off his satisfaction at a point on the scale short of complete satiation. This point -- the smallest utility obtainable in the circumstances, assuming the most thorough possible utilisation of the goods -- is of peculiar importance, both for the act of valuation and for economic life. To it refer the expressions, "Werth des letzten Atoms," of Gossen, "Final degree of utility,"or "Terminal utility" of Jevons; and "Intensite du dernier besoin satisfait (rarete)" of Walras. Menger uses no particular designation. The name "Marginal Utility" was suggested by me (Ursprung des Werthes, p. 128), and has since been generally accepted.
Where the supply of goods is too scanty to satisfy every sensation of desire, the necessary break must be so made that it will be felt as little as possible. This will be the case when we begin by satisfying the most intense sensations of want, and go on to extend to its utmost the compass of enjoyment; or, in other words, when we reach, in unbroken satisfaction, the lowest possible marginal point of enjoyment. Economic conduct requires that the marginal utility in this sense be placed as low as possible. The means by which to reach this end are, on the one hand, the utmost possible quantitative exploitation of goods, and, on the other hand, the utmost care in choosing how the goods are to be employed where there are several competing ways of employing them. Such a competition of employments may arise from two circumstances -- first, where goods are capable of manifold and various uses, and, second, where supplies are accumulated and their consumption should be spread over periods of time. In the first case our concern must be to choose between the separate forms of employment, and to keep the economic balance even; in the second, to distribute the goods so as best to meet the wants of the whole period.
The difference between the various satiation scales of wants comes into play in the case of goods of many-sided usefulness.
Every different kind of employment has its own particular scale of satiation, with a culminating point peculiar to itself and a course of satisfaction peculiar to itself. On account of this the determination of the marginal utility in the given case becomes a very complicated matter. Its principle will be best explained by an example, and we need be at no loss for examples, as goods of manifold utility are numerous enough. The most important are found among the means of production. Who could count up the services which iron, wood, or coal is capable of rendering? Or those for which human labour is fitted? The most many-sided of all goods is, however, money; through exchange it can be turned into almost any other commodity, and thus made serviceable for the satisfaction of almost any want. From no other commodity can we obtain so clear a presentation of the idea of "marginal utility." I therefore take it as example, although money is really useful only as a medium, and presupposes the existence of exchange, a phenomenon of which we shall not treat till the following book.
