Thus much I have said for the sake of showing what is not the use of Mr. Ricardo's principle in the design of its author; in order that he may be no longer exposed to the false criticism of those who are looking for what is not to be found, nor ought to be found, [Footnote: At p. 36 of "The Measure of Value" (in the footnote), this misconception as to Mr. Ricardo appears in a still grosser shape; for not only does Mr. Malthus speak of a "concession" (as he calls it) of Mr. Ricardo as being "quite fatal" to the notion of a standard of value,--as though it were an object with Mr. Ricardo to establish such a standard,--but this standard, moreover, is now represented as being gold. And what objection does Mr. Malthus make to gold as a standard? The identical objection which Mr. Ricardo had himself insisted on in that very page of his third edition to which Mr. Malthus refers.] in his work. On quitting this part of the subject, I shall just observe that Mr. Malthus, in common with many others, attaches a most unreasonable importance to the discovery of a measure of value. I challenge any man to show that the great interests of Political Economy have at all suffered for want of such a measure, which at best would end in answering a few questions of unprofitable curiosity; whilst, on the other hand, without a knowledge of the ground on which value depends, or without some approximation to it, Political Economy could not exist at all, except as a heap of baseless opinions. _Phæd_. Now, then, having cleared away the imaginary uses of Mr. Ricardo's principle, let us hear something of its real uses. _X_. The most important of these I expressed in the last words I uttered: _That_ without which a science cannot exist is commensurate in use with the science itself; being the fundamental law, it will testify its own importance in the changes which it will impress on all the derivative laws. For the main use of Mr. Ricardo's principle, I refer you therefore to all Political Economy. Meantime, I will notice here the immediate services which it has rendered by liberating the student from those perplexities which previously embarrassed him on his first introduction to the science; I mention two cases by way of specimen.