_Phæd_. I understand your distinction; and in which sense do you say that Mr. Malthus has used the term Measure of Value--in the sense of a ground, or of a criterion? _X_. In both senses; he talks of it as "_accounting for_" the value of A, in which case it means a ground of value; and as "_estimating_" the value of A, in which case it means a criterion of value. I mention these expressions as instances; but, the truth is, that, throughout his essay entitled "The Measure of Value Stated and Illustrated" and throughout his "Political Economy" (but especially in the second chapter, entitled "The Nature and Measures of Value"), he uniformly confounds the two ideas of a ground and a criterion of value under a much greater variety of expressions than I have time to enumerate. _Phil_. But, admitting that Mr. Malthus has proceeded on the misconception you state, what is the specific injury which has thence resulted to Mr. Ricardo? _X_. I am speaking at present of the uses to be derived from Mr. Ricardo's principle of value. Now, if it had been proposed as a measure of value, we might justly demand that it should be "ready and easy of application," to adopt the words of Mr. Malthus ("Measure of Value," p. 54); but it is manifestly not so; for the quantity of labor employed in producing A "could not in many cases" (as Mr. Malthus truly objects) "be ascertained without considerable difficulty;" in most cases, indeed, it could not be ascertained at all. A measure of value, however, which cannot be practically applied, is worthless; as a measure of value, therefore, Mr. Ricardo's law of value is worthless; and if it had been offered as such by its author, the blame would have settled on Mr. Ricardo; as it is, it settles on Mr. Malthus, who has grounded an imaginary triumph on his own gross misconception. For Mr. Ricardo never dreamed of offering a standard or fixed measure of value, or of tolerating any pretended measure of that sort, by whomsoever offered.