It has been widely held that war has played an essential part in the
evolutionary struggle for survival among our animal ancestors, that war
has been a factor of the first importance in the social development of
primitive human races, and that war always will be an essential method
of preserving the human virtues even in the highest civilisation. It
must be observed that these are three separate and quite distinct
propositions. It is possible to accept one, or even two, of them without
affirming them all. If we wish to clear our minds of confusion on this
matter, so vital to our civilisation, we must face each of the questions
by itself.

It has sometimes been maintained--never more energetically than to-day,
especially among the nations which most eagerly entered the present
conflict--that war is a biological necessity. War, we are told, is
a manifestation of the "Struggle for Life"; it is the inevitable
application to mankind of the Darwinian "law" of natural selection.
There are, however, two capital and final objections to this view. On
the one hand it is not supported by anything that Darwin himself said,
and on the other hand it is denied as a fact by those authorities on
natural history who speak with most knowledge. That Darwin regarded war
as an insignificant or even non-existent part of natural selection must
be clear to all who have read his books. He was careful to state that he
used the term "struggle for existence" in a "metaphorical sense," and
the dominant factors in the struggle for existence, as Darwin understood
it, were natural suitability to the organic and inorganic environment
and the capacity for adaptation to circumstances; one species flourishes
while a less efficient species living alongside it languishes, yet they
may never come in actual contact and there is nothing in the least
approaching human warfare. The conditions much more resemble what, among