PREFACE 
The goods and services that constitute our national income 
are valued severally and collectively with a fair amount of 
accuracy in terms of money. For a gold standard, though by no 
means perfect for the work of monetary measurement, is stable 
and has a single definite meaning to all men. By means of it we 
can estimate the rates of growth or decline in our industry, as 
an aggregate or in its several departments, and the quantities of 
output and consumption of the various products. We can com- 
pare the growth of our national wealth with that of other nations. 
But how far can these measurements of concrete wealth fur- 
nish reliable information regarding the vital values, the human 
welfare, which all economic processes are designed to yield? 
Though it will be generally admitted that every increase of 
economic wealth is in some measure conducive to welfare, every 
decrease to illfare, nobody will pretend even approximately to 
declare what that measure is, or to lay down any explicit rules 
relating wealth to welfare, either for an individual or a nation. 
Indeed, even the general assumption that every growth of wealth 
enhances welfare cannot be admitted without qualification. An 
injurious excess of income is possible for an individual, perhaps 
for a nation, and the national welfare which an increased volume 
of wealth seems capable of yielding might be more than cancelled 
by a distribution which bestowed upon a few an increased share 
of the larger wealth, or by an aggravation of the toil of the pro- 
ducers. 
Such obvious considerations drive us to seek some intelligible 
and consistent method of human valuation for economic goods 
and processes. To find a standard of human welfare as stable 
and as generally acceptable as the monetary standard is mani- 
festly impossible. Indeed, the difficulties attending any sort 
of calculus of vital values might appear insuperable, were it not 
for one reflection. Every statesman, social reformer, philan- 
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