F.— ECONOMIC SCIENCE AND STATISTICS 147 



The map is to some extent hypothetical. It supposes that various 

 activities may be interpreted as notifications of preferences. On the other 

 hand it is drawn with reference to the facts of the situation, assuming, if 

 appropriate, such matters as private property, private ownership of land, 

 unequal division of wealth, even special types of banking institution, 

 company organisation, etc., and traces how the mutual notification, which 

 it supposes to be intended, operates in these conditions. 



Two points may be noted, (i) By means of the map we are enabled 

 to get a view of the economic field as a whole. This is necessary for 

 prescription. A particular piece of legislation may be well designed to 

 secure its specific object. All reasonable men will wish to know, and it is 

 the economist's task to say, how this fits in with the larger purpose, for 

 which the whole economic mechanism is designed. To what extent does 

 the specific objective militate against or further the more general purpose ?^ 

 This can be studied by reference to the analytical conspectus. (2) Our 

 right to interpret observed phenomena as constituting the mutual expres- 

 sion of preferences depends in the last analysis on introspection. An 

 observant visitor from Mars who knew nothing of the nature of desire, 

 purpose and will, might well be unable to make this necessary link ; he 

 could become expert in the knowledge of causal sequences, but for lack 

 of the necessary interpretation would be unable to give advice on the basis 

 of the conspectus.'' 



The map is related to the criterion of preference by this principle, that 

 the more effective the system of mutual notification attained, the more 

 fully are preferences likely to be realised. Reference may be made to the 

 example of an import duty on wheat. We may know enough of the 

 existing organisation of markets to be sure that this will impose an obstruc- 

 tion to effective mutual notification. We infer that in the presence of this 

 obstruction preferences are less likely to be secured. The validity of this 

 inference depends upon the correctitude of our interpretation of existing 

 market processes. It is independent of knowledge how individuals will 

 react to the obstruction,' namely, the consequent course of prices, wages, 

 etc., which we should have to know if we were required to give a full 

 statement of consequences before prescribing, but which we only could 

 know if our causal knowledge were fuller than it is. 



How far the facts of real life correspond to those envisaged in the map 

 is a matter of observation and it should be subjected to continuous check. 

 Economists of the past were perhaps too hasty in assuming exact corre- 

 spondence. On the basis of the assumption and the criterion that the 



* If I interpret him aright, this account is in accordance with the view expressed 

 by Prof. Robbins in his section on ' rationality ' in the concluding section of the 

 Nature and Significance of Economic Science. Cp. also Prof. G. Cassel, Funda- 

 mental Thoughts on Economics, p. 14. 



' This is in principle the position to which Prof. Cassel would reduce 

 economists by e.xtruding all reference to utility from economics. Cp. Funda- 

 mental Thoughts on Economics , pp. 66-70. In another place, however, he recog- 

 nises the fundamental part played by the notion of need, which is only another 

 word for utility, cp. Theory of Social Economy, vol. i, pp. 8-9 (tr. McCabe). 



' In exceptional cases the precise nature of this reaction might.be relevant. 

 Our map read in conjunction with our interpretation of the market should warn 

 us if there is any probability of this. 



