326 NATURE OF CAPITAL AND INCOME  [Cmar. XVIII 
this fact, combined with the fact that every transaction ”’ 
is also double-faced, grows, as we have seen, the entire 
theory of double-entry bookkeeping. 
Out of the entire mass of instruments thus acting and 
reacting upon each other, there finally emerges an uncan- 
celed or net income which does not represent a mere transfer 
from one category to another within the mass, but an actual 
contribution issuing from the mass to the benefit of man, 
the owner. These final elements are his real income. In 
the last analysis they consist purely of subjective or psychie 
satisfactions; that is, of conscious desirable experiences. 
§3 
But these desirable mental experiences occur at the sacri- 
fice of certain undesirable ones, namely, of efforts. The 
subjective efforts put forth for the sake of subjective satis- 
factions constitute the net or uncanceled elements of outgo. 
Thus we see that, side by side with the objective income 
and outgo stream, and as the final result of that stream, there 
exists its subjective counterpart, namely, the stream of ef- 
forts and satisfactions. In thesameway, there exists, side by 
side with the objective mass of capital, the subjective esteem 
in which this capital is held, namely, what we have called 
its desirability, or utility. If efforts and satisfactions are 
called subjective income, desirability or utility should be 
called subjective capital. The same antithesis of time 
applies to the subjective as to the objective; desirability 
is a state of mind at an instant of time; efforts and satis- 
factions are experiences through a period of time. Desir- 
ability stands for anticipated efforts and satisfactions, just 
as objective capital stands for anticipated services. We 
thus see in the mind of man a microcosm of the objective 
economic world, consisting of desires, efforts, and satis- 
factions, corresponding respectively in the objective world 
to capital, outgo, and income.