The New York Times presents the hopeful findings of researchers studying war.
Natalie Angier writes (excerpt):
In the heartening if admittedly provisional opinion of a number of researchers who study warfare, aggression, and the evolutionary roots of conflict, the great philosopher was, for once, whistling in a cave. As they see it, blood lust and the desire to wage war are by no means innate. To the contrary, recent studies in the field of game theory show just how readily human beings establish cooperative networks with one another, and how quickly a cooperative strategy reaches a point of so-called fixation. Researchers argue that one need not be a Pollyanna, or even an aging hippie, to imagine a human future in which war is rare and universally condemned.
They point out that slavery was long an accepted fact of life; if your side lost the battle, tough break, the wife and kids were shipped off as slaves to the victors. Now, when cases of slavery arise in the news, they are considered perverse and unseemly.