158 ECONOMIC ESSAYS IN HONOR OF JOHN BATES CLARK 
uch real meaning do such curves have? If so-called “marginal 
tility” of anything, (or, as I prefer to say, if the want-for-one- 
more unit of anything) is a true mathematical quantity, should 
ot that marginal want be measurable? 
In my first economic publication * I endeavored to show that 
his magnitude is measurable,—in theory at least. My object 
ere is to go one step further and to show that even the problem 
f statistically measuring it should not be considered insoluble. 
f this contention is justified, the appearance of unreality which 
as surrounded the subject ought to disappear, and, if or when we 
actually reach even a rough numerical measurement so that the 
subject enters Statistical Economics, the interest in it will be 
evived and increased. 
It is noteworthy that even Jevons, one of the originators of 
he concept of the “want-for-one-more,” (or, as he called it, 
‘final degree of utility”), and an enthusiastic believer in 
mathematical analysis, seemed to doubt the possibility of giving 
o that concept the full fledged status of a measurable quantity. 
e said, “We can seldom or never affirm that one pleasure is an 
pe multiple of another,” * and again, “I hesitate to say that 
men will ever have the means for measuring directly the feelings 
of the human heart. A unit of pleasure or of pain is difficult 
even to conceive; but it is the amount of these feelings which is 
continually prompting us to buying and selling, borrowing and 
ending laboring and resting, producing and consuming; and ut is 
rom the quantitative effects of the feelings that we t estimate 
heir comparative amounts.” * 
fr scepticism as to possibly measuring human wants is 
especially remarkable in view of Jevons’ statement: “ ‘But where,’ 
he reader will perhaps ask, ‘are your numerical data for estimat- 
ng pleasures and pains in Political Economy?’ I answer, that 
y numerical data are more abundant and precise than those 
ossessed by any other science, but that we have not yet known 
how to employ them. The very abundance of our data is per- 
plexing. There is not a clerk nor bookkeeper in the country who 
is not engaged in recording numerical facts for the economist. 
Op. Cit. pp. 11-24, 86-89. So far as I know this is the only attempt 
(other than Edgeworth’s therein cited) of treating “utility” or “want” as a 
definite mathematical quantity. 
* Theory of Political Economy, p. 13. 
8 Op. cit., p. 11.