According to Lawrence Keeley, "90-95% of known societies engage in
war". Why? What compels homo sapiens to kill each other? Why do we
fight? Part one will describe two hypotheses.

War is Rational:
Sun
Tzu argued that political struggles would eventually lead to armed
conflict. Clausewitz took this one step further by saying that "war is
a mere continuation of policy by other means". Machiavelli completed
this entire line of thought by saying that war was the most efficient
means of attaining any political goal.

War is Inevitable:
Hobbes
argued that humans are inherently violent. Raymond Dart and Robert
Ardrey found a scientific basis for this by claiming that homo sapiens
became the dominant humanoid through their martial prowess (and we have
kept this prowess ever since). Another group of philosophers believe
that war can be attributed to the reckless aggression caused by
testosterone in males.

For more information, read:
Sun Tzu's Art of War
Clausewitz's On War
Machiavelli's The Prince
Mao's Quotations
Hobbes' Leviathan

Military History Podcast is sponsored by Armchair General Magazine