112 Irving Fisher — Mathematical investigations 



Mathematical method is making a new set of classifications based 

 on mathematical properties. Thus the classification by Auspitz und 

 Lieben of all commodities into three groups* is, I believe, a new 

 one, and one suggested by, and readily discussed by the use of their 

 diagrams. The classification of capital into free and sunk is one 

 which is emphasized by the mathematical writers, as Marshall, and 

 is bearing fruit. f 



I believe therefore that mathematical method has made several 

 real contributions to economics, and that it is destined to make more. 

 To verify this statement I would refer the reader to the books men- 

 tioned in the bibliography among recent writers, especially Walras, 

 Auspitz & Lieben, Marshall, Edgeworth, Wicksteed and Cunyng- 

 hame ; also, if it is proper to include those writers, who while 

 avoiding mathematical language are interpreting and extending 

 the same ideas, Menger, Wieser, Bohm-Bawerk, Clark and Hobson. 



It may not be amiss to present a list of quotations from those who 

 have pursued or admired the mathematical path : 



WhewellX says : [Mathematical method in mechanics saves scien- 

 tists three errors, viz :] " They might have assumed their principles 

 wrongly, they might have reasoned falsely from them in conse- 

 quence of the complexity of the problem, or they might have 

 neglected the disturbing causes which interfered with the effect of 

 the principal forces. * * * It appears, I think, that the sciences of 

 mechanics and political economy are so far analogous that some- 

 thing of the same advantage may be looked for from the application 

 of mathematics in the case of political economy." Again :§ "This 

 mode of treatment might be expected to show more clearly than 

 any other within what limits and under what conditions propositions 

 in political economy are true." 



Gournot :\ L'emploi des signes mathematiques, est chose naturelle 

 toutes les fois qu'il s'agit de discuter des relations entre des gran- 

 deurs ; et lors meme qu'ils ne seraient pas rigoureusement necess- 

 aires, s'ils peuvent faciliter I'exposition, la rendre plus concise, mettre 

 sur la voie de developpements plus etendus, prevenir les ecarts 



* Page 46. 



f See Cunyngliame, Geom. Meth. of treating exchange value, monopoly, and 

 rent. Econ. Jonr., March, '93, p. 35. 



X Cambridge Philosophical Transactions, 1830, p. 194. 



§ Cambridge Philosophical Transactions, 1856, p. 1. 



II Principes math, de la th^orie des richesses, 1838. Preface, p. viii. 



