Note 844 — Chapter I · : THE HISTORICAL SCHOOL AND THE CONFLICT OF METHODS

Cf. Menger, loc. cit., p. 79: “The student of pure mechanics does not deny the existence of air or friction, any more than the student of pure mathematics denies the existence of real bodies, of surfaces, and lines, or the student of pure chemistry denies the influence of physical forces or the physicist the presence of chemical factors in actual phenomena, although each of these sciences only considers one side of the real world, making an abstraction of every other aspect of it. Nor does the economist pretend that men are only moved by egoism or that they are infallible and omniscient because they envisage social life from the point of view of the free play of individual interest uninfluenced by other considerations, by sin or ignorance.” Wagner and Marshall take the same view.