378 POSTSCRIPT 
national prosperity have an abiding interest. But it is 
important to remember that the Science of Political Economy, 
as they formulated it, only deals with one aspect of human 
life,—or with the material and physical conditions of exist- 
ence and progress, rather than with life itsglf> These con- 
stitute a very important aspect ; and they are very difficult to 
deal with, as the severance between private and public in- 
terest, or the divergence of temporarily conflicting interests, 
is more marked in this connection than in the other elements 
of welfare. The interests of landed and moneyed men, or of 
capital and labour, or of an old and an undeveloped country, 
often are distinct, and the chief problem of modern political 
life is to prevent any one interest from becoming dominant 
and allowing itself to pursue its own advantage in disregard 
of the common weal. 
Since 1832, when England became consciously demo- 
cratic, and still more since 1874, when the new principles 
were more thoroughly applied, the physical well-being of 
labour has been kept very prominently in view by English 
legislators and administrators. Political power rests with 
‘o the the working classes, and they may possibly use it so as to 
nterests 
of labour burden the owners of property unduly, and prevent the 
in England py ntion of capital, or so as to harass emplovers in the 
| An attempt has been made by Jevons and his followers to revolutionise 
Political Economy and to recast it in a form in which it appears to offer a scientific 
account of Human Welfare. They start from the conception, which Adam Smith 
liscarded, of value-in-use, instead of value-in-exchange, and explain transactions 
‘n terms of the degrees of utility or disutility involved. This is a convenient 
node of statement for treating certain problems, particularly those of con- 
sumption, but the analysis of subjective motives has always seemed to me 
a cumbrous and inconvenient way of approaching the facts of the actual exchange 
of goods, a8 it goes on in the world. It is comparatively easy to take a certain 
type of human being and analyse his probable conduct, but the principles thus 
obtained are not real generalisations from observed fact (Cunningham, Plea for 
Pure Theory, in Economic Review, nm. 85). It is difficult to see within what 
limits they are applicable, or what corrections it is necessary to apply in order to 
make them the basis of practical maxims. According to Adam Smith’s treatment 
exchange-value is the fundamental conception; and in modern life the conditions 
of exchange dominate over the methods of production and the terms of distri. 
bution. The most recent English writers, Professor Nicholson in his elaborate 
jreatise, and Mr Devas in his manual, while embodying the results obtained on 
the new methods, show a decided reaction against the mode of statement intro- 
duced by Jevons, and a tendency to revert to the objective treatment which 
vas adornted by Adam Smith and the (Classical Economists.