likenesses
and differences, and especially the recognition of the nature of
death, and the advantages of killing rather than merely overcoming an
enemy, the discovery of the use of weapons, introduced warfare into
the world. Warfare is, then, not simply the negation of some original
principle of mutual aid, nor yet an expression of instinctive
aggressiveness or cruelty, but it is a product of original endowment,
of conditions of life, and of intelligence all together. It is
practical, but at no stage can it be said to be _wholly_ practical.
Changes must have taken place in warfare as in other social reactions
as men passed through a number of stages from primitive wandering or a
relatively unstable life to a stable life, but the motives of conflict
cannot have been added to in any essential way. Through all the course
of history all the motives that originally made individuals of a group
or the groups as wholes antagonistic have remained, although the
mental processes have become generalized, fused and transformed. If
Gumplowicz is right we can still detect in any great society to-day
all the primitive individual and group animosities, tempered down and
held in check by laws and customs, but still existent and by no means
overcome and made innocuous.

These motives of warfare might best be traced out in four more or less
definite principles of conduct, or four purposes of war that appear
throughout primitive life. These are: 1) thievery, including wife
capture; 2) the fear motive; 3) cannibalism; 4) the display motive,
with the desire to intimidate and to display power (more or less
closely associated with the play motive, the love of hunting, gaming
and the dramatic motive).

Cannibalism, of course, is a special expression of the predatory
motive in general, or it is mainly that. Cannibalism was certainly
established early in primitive life, at least early enough to antedate
all religion, and although its origin and history are shrouded in
mystery, the motive was quite certainly practical. Evidently it was
widespread if not universal. Whether it was introduced as a result of
a failure of animal food, as some think, or has a still more simple
explanation as a part of the original impulse which led men at a
certain stage of their development to become hunters, cannot be
determined. We know, however, that the alien human being was to some
extent included under the same concepts as the animal enemy and prey,
and presuma