“War, in one form or another, appeared with the first man. At the dawn of history, its morality was not questioned; it was simply a fact, like drought or disease”, said Barack Obama when he accepted the Nobel Peace Prize in 2009. The then US president was voicing a popular belief, writes primatologist Carel van Schaik in the recently published book Waarom we vrede willen, maar oorlog voeren [Why We Want Peace But Make War] (Uitgeverij Balans, ISBN 978 94 63824 23 1): the idea that humanity is hardwired for war, and war is just a regrettable but inevitable fact of life.
For a long time, Van Schaik himself shared that belief, the Swiss-based professor admits during a Teams interview. That was until he began working on the book with historian Kai Michel and archaeologist Harald Meller. Together, they examined the history of Homo sapiens – the modern human species that evolved some 300,000 years ago – and arguments for the human propensity for war. What they found made Van Schaik change his mind.
No mass graves
“Take my own field”, he says. “Chimpanzees are the only primates apart from humans that engage in group attacks on members of their own species. It was long thought that if our closest genetic relatives behave like that, then group violence must be in our nature too.” But research on bonobos – genetically closely related to both chimpanzees and humans – has since flourished. And what did it reveal? “Bonobos rarely attack one another.” In other words, our taste for war cannot be explained by our genes. “We need to breathe and eat. We do not need to wage war.”
Moreover, Van Schaik points out, research on human violence tends to focus on the very tail end of our species’ existence: the past 10,000 to 12,000 years, when humans began to settle and take up farming. But Homo sapiens is far older than that – and for almost the entirety of our history we lived as nomads, roaming in groups and surviving on what we could hunt and gather. According to Van Schaik, all the evidence suggests that these nomadic groups lived in relative peace, resolving conflicts by negotiating or simply moving on. “We’re quite sure about this”, he says, citing archaeological findings from the nomadic hunter-gatherer period. “Whatever we find, there are no mass graves, no evidence of defensive structures, no depictions of battle and no weapons buried with the dead” – all things you would expect if these groups engaged in warfare. “That’s negative evidence”, he admits, “but we also have positive evidence. Ethnographic research among Aboriginal peoples in Australia, for example, shows that nomadic hunter-gatherers hardly ever wage war against each other.”
Defensive instinct
If armed conflict is not innate to human nature, why are today’s headlines full of it? War, argues Van Schaik, is a cultural phenomenon that flourishes under certain conditions – and those conditions arose when humans began to settle and farm. “When we were nomads, encounters with other groups mainly served as opportunities to exchange partners, knowledge, tools. Researchers have found volcanic glass tools hundreds of kilometres from the source. Groups also had agreements to share food in hard times. But that no longer works once you settle somewhere and start stockpiling your own supplies. You no longer need to share with others, so you start defending what you have instead. That creates the conditions for war. And that’s why, from that point on, we start finding evidence of mass graves and defensive structures. Once agriculture became productive enough to generate food surpluses, war could even become routine, because people could now afford to maintain soldiers. This is what we see in the first cities, which emerged 5,000 to 6,000 years ago.”
Even then, he explains, war does not simply happen automatically. “People have a natural instinct to defend themselves”, but attacking, let alone killing, members of our own species? “We’re very reluctant to do that. There is such a thing as Tötungshemmung, an inhibition against killing. There’s a reason why we say war is ‘unleashed’: that defensive instinct has to be overridden. Offensive wars have to be justified. Ordinary people must feel like they stand to gain something that outweighs the risk of dying in battle.” One notorious example of such manipulation is Adolf Hitler’s speech after invading Poland. He claimed that Poles had attacked Germans: “He said they were just ‘firing back’. In reality, the border incidents Hitler was referring to had been staged by the Germans.” Van Schaik sighs. “Sadly, such manipulation is far from rare.”
Pacifism
Still, the book isn’t a pessimistic one – quite the opposite, in fact. “We can strengthen the democratic institutions that protect peace, even when people’s interests clash”, Van Schaik says cheerfully. “A functioning democracy is unlikely to go to war with its neighbours. And we can prevent people from being manipulated by promoting free speech and a free press that exposes lies and fake news.”
In that light, how does Van Schaik view politics in his native country [this interview took place just before the 2025 Dutch general election]? He chuckles. “The book deliberately steers clear of current events, so it won’t date too quickly. Let’s just say that any form of populism carries a potential risk of warmongering. But I don’t see the Netherlands heading in that direction anytime soon. We’re just a small country, after all, and our military isn’t particularly strong.”
Finally, do he and his co-authors ever get accused of naivety for arguing that war is not an inevitable part of human nature? He laughs again. “That’s precisely what we tried to avoid by stating that defending yourself against attack is legitimate. Pacifism – a world where conflicts are resolved peacefully – is the goal, not the path to get there.”