48 ECONOMIC ESSAYS IN HONOR OF JOHN BATES CLARK 
static formulas. And in the third place, throughout dynamics 
there will arise situations which will be clarified by a reference to 
a set of static assumptions—not necessarily a complete static 
economy—for purposes of comparison. This will probably, more 
often than not, take the form of that kind of inverse deduction 
already mentioned; the reasoning running thus: to bring about 
such-and-such results, such-and-such conditions are necessary. 
Actual conditions differ in such-and-such respects. Hence we 
should expect actual results to differ in such-and-such general 
ways. Or, if actual results differ in given fashion from the 
static, a probability arises that the difference is due to the dis- 
crepancy of conditions from the static ones. This is a use of 
static reasoning eminently suited to dynamic studies. 
reo 
Deo 
2. Orin of Statics 
The contrast which we are considering is between realistic 
economics and economics simplified by the method of static 
abstraction, which studies levels of equilibrium under abstract 
conditions. These make equilibrium possible (1) by eliminating 
elements of disturbance and (2) by confining the adaptive forces 
and processes to those which are self-limiting and not cumulative 
in character. Static economics, of one sort at least, is complete 
in its main outlines. It is not wholly past the stage of controversy, 
nor of further developments, but the controversies are largely 
matters of proper formulation rather than of the essential logic 
of the main structure; and the further developments, aside from 
reformulations, are matters of detailed refinement whose accuracy 
is hardly justified in view of the wide gap between the assumed 
conditions on which the whole structure rests and the reality in 
the interpretation of which its ultimate service must lie. The 
significant field for present work lies in the development of more 
realistic economics, which may be defined, in contradistinction to 
statics, as dynamics. Unlike statics, dynamics is in its infancy, 
and very possibly is destined always to remain in that stage, on 
account of the fact that conditions change so fast and so endlessly 
that analysis and interpretation cannot overtake them. 
But the difference between statics and dynamics is not merely 
a matter of simplification of the data of the problem. This 
simplification has its roots in something deeper; a delimitation of 
the problem itself. Hence we should be prepared, in stepping out-