CHAPTER IX. SUMMARY OF THE REASONS FOR ADOPTING THE SUBJOINED DEFINITION OF THE MEASURE OF VALUE. As a preliminary, it may be proper to state, that it seems absolutely essential to the language of political economy, that the expression _value of a commodity_, like the expression _price of a commodity_, should have some fixed and determined sense attached to it. Every person who has either written or talked on the subject of political economy, has been constantly in the habit of using the term without specifically expressing the object of comparison intended: and if it were true, that we might with equal propriety suppose any one of a thousand different objects referred to, it might easily be shown, that all past writers who had used the term value had talked the greatest nonsense; and all future writers must abound in the most tedious circumlocutions and the most futile propositions. But the author of the Critical Dissertation on Value has certainly done injustice to the writers who have gone before him, in supposing that when they have used the term value of a commodity, no reference was implied, if it was not expressed. As I stated before, they must be considered as referring, in some form or other, either to its general power of purchasing, or, to the estimation in which it was held, determined by the state of its supply compared with the demand, and, on an average, by the elementary costs of production; and as it would be perfectly ridiculous to suppose, that when the values of commodities, at different periods, are spoken of generally, by respectable writers, they could mean to refer to individual commodities not intended to represent, more or less accurately, the above objects of reference; it is obvious, that the ultimate reference implied must be confined to one of these, or their equivalents. I have already given my reasons for thinking it more correct and useful to refer to the estimation in which a commodity is held, determined as above described, rather than to its general power of purchasing; but, as others may be of a different opinion, it may be useful to include among the reasons for adopting labour as a measure of value, its qualities as a measure of the general power of purchasing.