Why humanity wages war

In 1991 two hikers in the Italian Alps stumbled on a mummified body buried in the ice. The Iceman, it turned out, died more than 5,000 years ago. At first, archeologists assumed he’d fallen in a snowstorm and frozen to death. Then they discovered various cuts and bruises on his body and an arrowhead embedded in his shoulder. They also found traces of blood on the stone knife he was carrying. Most likely, he died fighting.

Canadian historian Margaret MacMillan regards the Iceman story as emblematic of our violent nature. Humans are a quarrelsome lot with a special talent for waging war. In her book War: How Conflict Shaped Us, she argues that warfare is so deeply embedded in human history that we barely recognize its ripple effects. Some are obvious, like the rise and fall of nations, but others can be surprising. For all that we cherish peace, war has also galvanized social and political change, sometimes for the better. It’s also sparked scientific advances.

MacMillan is the author of several highly regarded histories of war and peace. She also has a personal interest in this subject. Her father and both her grandfathers served in wars, and her great grandfather was David Lloyd George, Britain’s prime minister during World War I. But she says her family history isn’t that unusual. “I’m in my 70s and most of us have had family members who were in the First World War or the Second World War or knew someone who was in either war,” she told me.