116 Irving Fisher — Mathematical investigations 



Cunyngharne :* "But curves play in the study of pol. econ. 

 much the same part as the moods and figures play in logic. They 

 do not perhaps assist in original thought, but they afford a 

 system by means of which error can be promptly and certainly 

 detected and demonstrated. And as in logic so in graphic pol. 

 econ. the chief difficulty is not to solve the problem, but to state it 

 in geometrical language." 



§8. 



Contrast with the preceding the following statements from a few 

 who can see nothing good in mathematical method : 



A writer in the "Saturday Review" (Nov. 11, 1871), quoted hj 

 Prof. Edgeworthf says of Jevons : " The e(|uations, * * * assum- 

 ing them to be legitimate, seem to us to be simply useless so long as 

 the functions are obviously indeterminable." [Mathematics studies 

 relations as well as calculations. Numerical indeterminabilit}^ is 

 common even in mathematical physics.] 



Cairnes'.X "Having weighed Prof. Jevons's argument to the best 

 of my abilit}^, and so far as this is possible for one unversed in 

 mathematics, I still adhere to my original view. So far as I can see, 

 economic truths are not discoverable through the instrumentality of 

 mathematics. If this view be unsound, there is at hand an easy 

 means of refutation — the production of an economic truth, not 

 before known, which has been thus arrived at ; but I am not aware 

 that up to the present any such evidence has been furnished of the 

 efiiciency of the mathematical method. In taking this ground, I 

 have no desire to den}^ that it may be possible to employ geometrical 

 diagrams or mathematical formul£e for the purpose of exhibiting 

 economic doctrines reached hy other paths, and it may be that there 

 are minds for which this mode of presenting the subject has advan- 

 tages. What I venture to deny is the doctrine which Prof. Jevons 

 and others have advanced — that economic knowledge can be ex- 

 tended by such means ; that mathematics can be ajiplied to the 

 development of economic truth, as it has been applied to the devel- 

 opment of mechanical and physical truth ; and, unless it can be 



""■ Geometrical methods of treating exchange value, monopoly .nid rent. H. 

 Cnnynghame. Econ. Jonr., March, '92, p. 35. 



f Math. -Psychics, p. 119. 



\ The Character and Logical Method of pol. econ. Neiv York, 1875. Preface, 

 See also, p. 122 ; also: Some leading principles of pol. econ. newly expounded. 

 Preface. 



