it
in terms of any single principle, or at least to prevent our finding a
single cause of war. We ought to try to see now how such a
psychological view of war stands in relation to certain more objective
views of it, which in a very general way may be said to be centered in
two closely related views. One is that war is almost exclusively an
economic phenomenon, and the other that war is the work of
individuals. One is the economic interpretation of history, and the
other is the great man view of history.

We still see a lingering theory that war is a result of the ancient
migratory or expansion impulse--that over-population and the pressure
of various economic conditions are the source of the impulses that
lead to war. We have seen reasons for believing, however, that war,
even in the beginning, has not been a wholly practical matter. Hunger,
pressure of population, migratory movements because of economic
conditions, will not explain the origin and the persistence of wars.
Wars are not simple as these views would imply, at any stage. That at
the present time economic advantage, whether or not it be the motive
of war, is in general not gained seems to be very clearly indicated.
The taking of colonies and other lands may be a detriment rather than
a gain to the conquering nation. The industry and the finance, of all
concerned in war, are likely to suffer disaster. Peace is the great
producer of wealth. War is a terrible destroyer of it. Ross says that
as industry progresses, wars become continually more expensive and
less profitable, that the drain is not upon man power so much as upon
economic power; nations bleed the treasure of one another until some
one of them is exhausted and must yield.

The theory that war is caused by the pressure of population,
especially as applied to the recent war, now appears to have been very
naive. It was maintained that Germany needed more room for her growing
population, that Germany must have more land at home and more
colonies. Claes (46), among several writers, shows that this is not
true. Germany had no pressing need of more land, except for political
purposes, or such land as provided the raw materials for her military
industries. Bourdon (67) maintains that it is not true that Germany's
population was becoming excessive. Le Bon (42) says that this theory
of over-population is a myth. Still others have shown that in a
country that is rapidly becoming industrial, as was Germany, wh