First, whether or not the policies concerned are fit to attain the ends which those recommending and applying them want to attain. Secondly, whether these policies do not perhaps produce effects which, from the point of view p. 28 of those recommending and applying them, are undesirable. It is true that the terms in which many economists, especially those of the older generations, expressed the result of their inquiries could easily be misinterpreted. In dealing with a definite policy they adopted a manner of speech which would have been adequate from the point of view of those who considered resorting to it in order to attain definite ends. Precisely because the economists were not biased and did not venture to question the acting men's choice of ends, they presented the result of their deliberation in a mode of expression which took the valuations of the actors for granted.
People aim at definite ends when resorting to a tariff or decreeing minimum wage rates.
One of the most famous of the theorems developed by the Classical economists, Ricardo's theory of comparative costs, is safe against all criticism, if we may judge by the fact that hundreds of passionate adversaries over a period of a hundred and forty years have failed to advance any tenable argument against it. It is much more than merely a theory dealing with the effects of free trade and protection. It is indispensable for understanding the origin of civilization and the course of history. Contrary to popular conceptions, it does not say that free trade is good and protection bad. It merely demonstrates that protection is not a means to increase the supply of goods produced.