"We’ve come to think that peace is normal, but that's not the reality": Margaret MacMillan on humanity's compulsion to go to war

In fact, a lot of anthropologists are now arguing that the entire organisation of human society is tied up with our ability to order ourselves to fight wars. Once you embark on war, you need structures and soldiers. You need someone to give the orders and someone to take the orders. And that all requires societal organisation: the two things are intimately linked. War has shaped how societies have developed, but societies’ shape has also determined the nature of war. So it’s real chicken-and-egg stuff.

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EC: War has taken many forms through history, so how have you gone about defining it?

MM: It’s very tricky, but the closest definition I’ve come to is that war is an organised act of violence against another organisation, with the end goal of forcing the other side to do what you want. Again, the organisation part is key. If I go and beat someone up in the street, that’s not a war, regardless of what we may call it. It’s one-on-one violence. Whether it’s a conflict between competing religious orders, a civil war, or one between two rival states, war involves organised bodies inflicting violence on one another.

EC: Why do you reject the assumptions that peace is the status quo and that war is simply a breakdown of that natural state?

MM: In recent history, most of us living in the west have been extremely lucky – we have not experienced war first hand, and we’ve lived through what some people call the ‘long peace’. As such, we’ve come to think that peace is normal, and that war is something that doesn’t really affect us – it happens on the other side of the world and involves other types of people.

But the reality is that war is rife elsewhere around the globe. If you take a good look at human history, it’s repeatedly been marked by war. I’m not saying that is a good or a bad thing, but it’s simply been the case. Whether it’s the Middle Ages, the Renaissance or the 18th, 19th and 20th centuries, it’s very hard to think of a century in European history that hasn’t witnessed war.

Whether it’s the Middle Ages, the Renaissance or the 20th century, it’s very hard to think of a period in European history that hasn’t witnessed war

So yes, I would argue that war isn’t just a disruption of normality, not just an absence of peace – it’s something we seem to keep returning to over and over again as a species. War is deeply woven into human history and I find that very interesting.

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EC: Have people’s motivations for going to war changed over the centuries?

MM: We need to understand the motivations on two levels. Firstly, there are the motivations prompting a large organisation – whether a feudal state, a kingdom or an empire – to go to war. These can cover anything from conquest or defence to questions of honour.

Then there are the motivations inspiring individuals to go to war, which could be even more complicated. Culture has played an important – and often surprising – role here.

You can look through the past and see cultures that were definitely warrior cultures, in which young men (occasionally women, but mainly men) were brought up to see fighting as one of the most noble things you could do. So there’s a desire for glory: young men often say that they want to test themselves in the heat of war.

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After the French Revolution there was a very new and important notion that everyone was a citizen rather than a subject. As a subject of the king you might owe the monarch a debt of duty, but you didn’t feel any kind of responsibility for the state. But as a citizen, the state belonged to you, so you were obliged to support and defend it. That’s one example of how culture has made a huge difference in how people fight, and whether they want to.

Social pressure has also played an important role in motivating people to go to war. In the Roman Republic, it was just assumed that all young men would volunteer to fight. It was seen as totally normal that you would leave your farm or your trade to go away to war, perhaps for as long as seven years. If you lived in a society in which you were expected to fight, it could be very difficult not to. We know that in the First World War, men were under tremendous pressure to sign up – women gave out white feathers to those they felt should have been enlisting, while conscientious objectors were shamed, vilified and imprisoned. On the front lines, many soldiers were forced by their own officers to fight – on pain of death.

Once in battle, what often seems to happen is that soldiers fight for those they are with. Countless memoirs recount that once you get into a war zone, you go ahead because you don’t want to let down the men you’re fighting alongside. Intense bonds of comradeship could develop, and again and again you see injured men desperate to get back to the front for fear of letting down their friends. So there’s definitely a mixture of motives.

EC: Has war ever benefited societies?

MM: One of war’s many paradoxes is that it has often led to progress. Things that seem impossible in peacetime suddenly become possible in wartime. In peacetime, governments will say that they simply can’t spend the money required for certain ambitious projects. But if you think your whole society is at stake, then suddenly you find the money. Governments find that they can tax a lot more during war, because the public appreciates the need to mobilise all national resources.

One example was the Manhattan Project to develop the first atom bomb. This was a hugely expensive enterprise, but during the Second World War people thought it simply had to be done. When it came to the crunch, the government was prepared to put up the money. As a result, we ended up with nuclear weapons but we also got nuclear power, which I think you can argue has been a positive thing. Another example is penicillin. It had already been discovered by Alexander Fleming in 1928, but was very expensive to mass produce. But then the bloodshed of the Second World War came along, and somehow that expense became bearable.

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Economic historians are producing some really interesting work that argues war can also lead to what they call a ‘compression of society’. This means that war can result in more people sharing in prosperity, with less of a gap between the very rich and the very poor. The poles are pushed together. During war, you tax the rich and also have to implement policies to keep the poorest parts of society onside – they need to be fed and looked after. Studies suggest that the average Briton was better fed during the Second World War than ever before. The period from 1914 to the 1960s probably saw the greatest equality in western societies, and I would argue that that was largely due to the impact of the world wars.

Another way that war has triggered societies to progress more recently has been through changing the position of women. The First World War provides a great example of this. A large part of why women in Britain were denied the vote – despite tireless campaigning – was because people thought they weren’t qualified to make important decisions, and didn’t have the capacity to do the same jobs as men. However, during the First World War, when men were away fighting, many traditionally male jobs fell to women. And it turned out that women could do all sorts of things that many people thought they would never be able to – such as driving tractors, working on factory assembly lines and running offices. After that, the opposition to women getting the vote simply melted away. In the heat of war, they had proven themselves worthy.

EC: Will war always be an inevitable part of change and development?

MM: It’s very difficult to tell. At the end of the Cold War, I think we hoped that humanity had somehow moved beyond war. And then the Iraq War broke out in 2003, and the war in Afghanistan, and now there’s conflict in Syria. I’m certainly not saying that war is inevitable – and I would hate to think that that was the case – but I just don’t see it disappearing any time soon.

In the future, it might well be that we don’t try to kill each other in battle, but instead move into areas such as cyberwar. With cyberwar there’s no need to send soldiers or ships off to tackle the enemy. Instead you can simply cripple the systems on which your opponents depend. If you think about how much societies now rely on computerised networks, you can see the potential.

Margaret MacMillan is a professor of history at the University of Toronto. She will be giving a virtual lecture on why humans go to war on Tuesday 13 October. Find out more here

This article was first published in the July 2018 edition of BBC History Magazine