20 
POLITICAL ECONOMY 
an all-embracing theory. The method de 
veloped by Dr. Marshall may be called the 
marginal method ; and associated with it in 
the most convincing modern speculations is 
the conception of individual experience, and 
even of society, as an organic whole. The two 
chief notions in economic theory to-day consist 
in seeing each item of experience as in contin 
uous relation with the rest of experience, and 
in explaining the definite results reached in 
economic affairs—the consequences of demand 
and supply, to use the expression sanctified 
by long usage—as largely brought about by 
the differences made to the totality of experi 
ence by the final activities of producing and 
consuming. It is difficult to expound these 
notions in brief, but their import will be 
brought out in each of the succeeding chapters 
of this book. On completing his perusal of 
what follows, the reader who returns again 
to this page will see on the instant what its 
vague phrases mean. In the technical lang 
uage of mathematics the chief part of the 
explanation of economic value, whether 
revealed in the prices of goods or the rates 
of international exchange, or the level of 
wages or the amount of interest, is to be found 
in the differentiation of economic experience 
—in observing the differences made to the