[31] "Even if we put aside all questions which involve a consideration of the effects of industrial institutions in modifying the habits and character of the classes of the community, ... that enough still remains to constitute a separate science, the mere enumeration of the chief terms of economics--wealth, value, exchange, credit, money, capital, and commodity--will suffice to show." Shirres, _Analysis of the Ideas of Economics_ (London, 1893), pp. 8 and 9. [32] "If a commodity were in no way useful, ... it would be destitute of exchangeable value; ... (but), possessing utility, commodities derive their exchangeable value from two sources," etc. Ricardo, _Political Economy_, chap, i, sect. I. [33] _Cf._, for instance, Senior, _Political Economy_ (London, 1872), particularly pp. 88, 89, and 130-135, where the wages of superintendence are, somewhat reluctantly, classed under profits; and the work of superintendence is thereupon conceived as being, immediately or remotely, an exercise of "abstinence" and a productive work. The illustration of the bill-broker is particularly apt. The like view of the wages of superintendence is an article of theory with more than one of the later descendants of the classical line. [34] _Cf._ Boehm-Bawerk, _Capital and Interest_, Books II and IV, as well as the Introduction and chaps. iv and v of Book I. Boehm-Bawerk's discussion bears less immediately on the present point than the similarity of the terms employed would suggest. [35] _Political Economy_, p. 87. [36] _Character and Logical Method of Political Economy_ (New York, 1875), p. 71. Cairnes may not be altogether representative of the high tide of classicism, but his characterisation of the science is none the less to the point. [37] Senior, _Political Economy_, p. 87. THE PRECONCEPTIONS OF ECONOMIC SCIENCE[1] III In what has already been said, it has appeared that the changes which have supervened in the preconceptions of the earlier economists constitute a somewhat orderly succession. The feature of chief interest in this development has been a gradual change in the received grounds of finality to which the successive generations of economists have brought their theoretical output, on which they have been content to rest their conclusions, and beyond which they have not been moved to push their analysis of events or their scrutiny of phenomena. There has been a fairly unbroken sequence of development in what may be called the canons of economic reality; or, to put it in other words, there has been a precession of the point of view from which facts have been handled and valued for the purpose of economic science.