DEMAND 
57 
The reader can judge for himself whether 
the alleged fecundity of the marginal method 
is borne out by its application to demand. We 
have strictly observed the limitations which 
render analysis of social facts so difficult. 
We have taken the experiences of a person in 
respect of his wanting or demanding as an 
indivisible whole, as we are told that we must 
by the most competent psychologists. And 
we have made no suspicious assumptions about 
the basis of these experiences ; for indeed we 
have made no assumptions at all as regards 
their basis, but have on the contrary accepted 
as our data the bare facts of wanting and 
demanding as they are directly revealed. 
But the door has not thereupon been shut 
against our scientific aspirations. By the 
marginal method, the simple device in this 
case of watching the differences made to the 
totality of a person’s experience—by differ 
entiating experience, as it is expressed in the 
first chapter—we have reached, under the 
guidance of Dr. Marshall in particular, general 
isations, which are adequately explanatory of 
demand for economic purposes and illumina 
ting (particularly the doctrine of consumer’s 
surplus) from the point of view of a philosophy 
of life, and which, as will transpire later, in 
conjunction with other generalisations having