OF DEMAND AND SUPPLY, IN THEIR RELATION TO
§ 1.That a thing may have any value in exchange, two conditions are necessary. It must be of some use; that is (as already explained) it must conduce to some purpose, satisfy some desire. No one will pay a price, or part with anything which serves some of his purposes, to obtain a thing which serves none of them. But, secondly, the thing must not only have some utility, there must also be some difficulty in its attainment. "Any article whatever," says Mr. De Quincey, "to obtain that artificial sort of value which is meant by exchange value, must begin by offering itself as a means to some desirable purpose; and secondly, even though possessing incontestably this preliminary advantage, it will never ascend to an exchange value in cases where it can be obtained gratuitously and without effort; of which last terms both are necessary as limitations. For often it will happen that some desirable object may be obtained gratuitously; stoop, and you gather it at your feet; but still, because the continued iteration of this stooping exacts a laborious effort, very soon it is found, that to gather for yourself virtually is not gratuitous. In the vast forests of the Canadas, at intervals, wild strawberries may be gratuitously gathered by shiploads: yet such is the exhaustion of a stooping posture, and of a labour so monotonous, that everybody is soon glad to resign the service into mercenary hands."
As was pointed out in the last chapter, the utility of a thing in the estimation of the purchaser, is the extreme limit
- Logic of Political Economy, p. 13.