100 MODERN MONETARY SYSTEMS 
The classical theory fails through lack of information 
as much as through carelessness in stating each problem 
exactly, and in ascertaining the actual conditions and the 
legal prescriptions which determine the actions of man, 
who is often unconsciously the originator of economic 
phenomena. But neither is it certain that the fundamental 
ideas, from which its conclusions are deduced, are quite 
firmly established; and they must themselves be sub- 
jected to criticism. 
In the remainder of the work we shall therefore follow 
a logical order ; and in the following chapter, which will be 
devoted to currency and prices, we shall attempt to dis- 
cover the fundamental ideas of the Quantity Theory. 
Thereupon we shall state the theory of the exchanges 
and its corollaries. 
Finally, we shall attempt, with the help of the data 
which have been ascertained, to define the idea of money 
and that of a monetary standard.