costs, but one may cost twice as much labor as the other, because the latter may cost more rent or interest than the former. Ricardo denied the influence of rent, and _assumed_ that interest preserves fairly constant proportions with the wage element. In our judgment, Ricardo was much the profounder of these two economists, but Malthus made the fortunate gain of presenting the empirical principles of value at the outset of his work, and in this way was led to adjust the labor theory to them, instead of doing the reverse, as Ricardo did. _Note on the Question of the Invariable Measure of Value in all Times and Places._ 7. Adam Smith made several general assertions concerning the power of a labor standard to measure value _in all times and places_. If mankind should live under conditions free from the rent of land and interest on capital, according to Smith the quantity of labor which commodities cost might properly be regarded as commensurate with the quantity which they command in exchange. Under actual conditions the command standard alone will apply. Ricardo became a steadfast critic of the idea that the labor-command standard could be thus used. He believed it to be impossible to find an invariable measure based on labor cost of production (as distinguished from labor commanded in exchange); but he made statements which implied that if a commodity existed which cost the same quantity of labor throughout time, it would be an invariable measure of “real value.” Then again he faltered in this view because “profits” enter into the cost of production of different articles in different degrees. The writer has found himself unable to reach a complete understanding of Ricardo’s section on this subject, Section vi of Chapter 1. Malthus always defended the labor-command standard of Smith, though in a vacillating way. In the end he adopted it in an unqualified form. (In the 2d and last edition of his _Principles_, the text being written just before his death.) With his last published discussion, appearing in 1836, the question practically disappeared from English political economy. Referring to this question, John Stuart Mill said: “it is necessary to touch upon the subject, if only to show how little there is to be said about it,” and concludes that the measure sought is impossible. J. B. Say wrote that “an invariable measure of value is a pure Chimera.”[126] Torrens expressed his judgment in words quoted from Lord Lauderdale: “Lord Lauderdale has justly observed that the search of economists after a measure of exchangeable value, is just as irrational and as hopeless as was that of the alchemists in quest of the philosopher’s stone.”[127] Well might the discussion be condemned by contemporaries and neglected by subsequent economists, for, especially in the lengthy writings of Malthus, the question was involved in distracting confusion, while the comparatively brief passage Smith devoted to the subject contains fatal contradictions.