LeBlanc contends that researchers have unearthed evidence of warfare as far back as they have looked in human prehistory, and ethnographers have observed significant levels of violence among hunter-gatherers such as the !Kung. In his book Constant Battles: Why We Fight (with Katherine E. Register), he espouses a bleak, Malthusian view of human prehistory, in which war keeps breaking out as surging populations outstrip food supplies. Warfare, he writes, “has been the inevitable consequence of our ecological-demographic propensities.”
Still, when asked point-blank if humans can stop fighting wars, LeBlanc replies, “Yes, I think it’s completely possible.” He notes that many warlike societies—notably Nazi Germany and imperial Japan and even the Yanomami, a notoriously fierce Amazonian tribe—have embraced peace. “Under certain circumstances,” he says, warfare “stops on a dime” as a result of ecological or cultural change. Two keys to peace, he believes, are controlling population growth and finding cheap alternatives to fossil fuels. “I was just in Germany,” LeBlanc exults, “and there are windmills everywhere!”
Despite the signs of progress against our belligerent side, all these scientists emphasize that if war is not inevitable, neither is peace. Major obstacles include religious fundamentalism, which not only triggers conflicts but also contributes to the suppression of women; global warming, which might produce ecological crises that spur social unrest and violence; overpopulation, particularly when it produces a surplus of unmarried, unemployed young men; and the proliferation of weapons of mass destruction.
Moreover, all the solutions to war come with caveats. Sapolsky suggests that eliminating poverty, while an important goal in its own right, may not extinguish war in all regions. Among baboons, lions, and other animals, aggression sometimes “goes up during periods of plenty because you have the energy to waste on stupid stuff rather than just trying to figure out where your next meal is coming from.” De Waal raises concern about female empowerment. Studies of apes and humans, he says, have found that while females fight less frequently than males, when they do fight, they “hold grudges much longer.”
A crucial first step toward ending war is to reject fatalism, in ourselves and in our political leaders. That is the view of the Harvard biologist Edward O. Wilson, who is renowned for his conservation efforts as well as for his emphasis on the genetic underpinnings of social behavior. A rangy man with a raptor’s long, narrow nose and sharp-eyed gaze, Wilson has not budged from his long-standing position that the propensity for group aggression, including war, is deeply ingrained in our history and nature. He notes, however, that group aggression is highly “labile,” taking many different forms and even vanishing under certain circumstances.
He is therefore confident that we will find ways to cease making war on nature as well as on each other, but it is a race against time and human destructiveness. “I’m optimistic about saving a large part of biodiversity,” he says, “but how much depends on what we do right now. And I think that once we face the problems underlying the origins of tribalism and religious extremism—face them frankly and look for the roots—then we’ll find a solution to those, too, in terms of an informed international negotiation system.” Wilson pauses and adds, “We have no option but optimism.”
