ABSTRACT
This chapter shows that political economy involves conceptions of a mathematical nature requiring to be analysed in a mathematical spirit. It suggests that there are certain departments of the science in which valuable aid may be derived from the actual employment of symbolical or diagrammatic methods. The fact that political economy is essentially concerned with quantitative relations, and involves mathematical notions, needs to be insisted upon, because to some economists the very idea of a mathematical treatment of economic problems is not only repugnant, but seems even absurd. The economist must by the aid of the symbols and diagrams be enabled to deduce conclusions having general validity under conditions that can be precisely determined. It is necessary to guard against a misapprehension that has led some economists to reject mathematical methods far too summarily. Professor Cairnes seems to imply that the employment of such methods is necessarily barren unless one can obtain premisses capable of being stated with numerical accuracy.
