THE RELATION BETWEEN STATICS AND DYNAMICS 61 
develop. When wealth is defined as that which is useful, limited 
in supply, appropriable and exchangeable, one does not at once 
realize that the last two characteristics are determined by the law, 
which therefore decides what shall be wealth, and what shall be 
the scope of economic study. 
A static economics may, perhaps, consider that it applies to 
whatever is appropriate and exchangeable under existing law. 
And if changes in the law result in broadening or narrowing the 
range of utilities which may be appropriated and bought or sold, 
the subject-matter to which the laws of static economics applies 
may be said to be enlarged or reduced; while the nature of the 
laws themselves remains unchanged. Thus these laws would be 
unaffected by such changes. But a realistic or dynamic economics 
will want to know all about such interesting changes, and will 
find therein most pregnant implications as to potential changes of 
the same sort which have not actually been made. Its picture of 
interests, utilities and disutilities will do its best to be comprehen~ 
sive, and not leave out any merely because the existing law 
declines to afford them specific protection. Indeed, interests which 
the law does not protect will be even more interesting than those 
which it does, for they will create problems and be the probable 
focusing points of future changes. 
The function of economic life is to serve the interests of human 
beings, so far as they may be served by business processes. Price 
is one agency for furthering that purpose, and those interests 
which command a price are the ones served by the system of 
private enterprise. Some interests are of such a character that 
they might command a price but do not under existing laws. If 
we are to judge the effectiveness with which the function is being 
performed, and the success of the system of private enterprise in 
performing it, we shall stultify the inquiry if we do not contem- 
plate the whole function, and include all the interests, whether 
they command a price or not. Otherwise we prejudge our inquiry 
by defining the function itself so as to include only that part of 
it which the particular agency covers. If we see no interests 
except those which command a price, we are hardly in a position 
to make a searching scrutiny of the adequacy of price as an 
agency for the furthering of interests. Thus the theory of inap- 
propriable wealth * and its twin-concept, uncompensated costs, 
become an important part of economic dynamics. 
1 See The Philosophy of Wealth, pp. 12-15.