What drives our addiction to war?

War has been a constant of the human experience for millennia. The question that continues to trouble historians is: why? Richard Overy considers the major factors that have fuelled conflict since before the emergence of the state, and what that might mean for us in the 21st century

Napoleon Bonaparte retreats from Moscow, as depicted in a painting from 1851. The French leader is the classic example of a man driven to wage war by a lust for power, says Richard Overy. (Photo by Getty Images)

Published: October 15, 2024 at 5:26 PM

Save

Why war? Albert Einstein posed this question to the psychologist Sigmund Freud in a series of letters sent in 1932, at the prompting of the League of Nations Institute for Intellectual Cooperation. He was disappointed with the answer. Freud told him that all animals – humans included – possessed a destructive “death drive” that could explain why they fought and why they would continue to do so.

Ad

Since that exchange, many of the world’s brightest minds have sought an answer that explains our propensity for collective violence – both over the millennia of recorded history and in all parts of the globe. This line of thought prompts two more questions.

What is warfare? And for how long have we been fighting wars? These points have, unsurprisingly, sparked major disagreements.

What is the definition of ‘war’?

Historians and social scientists have tended to define war as something that is a product of the state as an entity. They have been fought in periods when, and in places where, they could be planned, armies raised and resources paid for – in other words, over the past 4,000–5,000 years in areas where states emerged. Any violence below the level of the state is not warfare but, rather, feuding or raiding or ritual contests.

Evolutionary biologists and psychologists, on the other hand, see the emergence of warfare as having occurred much deeper in the human past, when small groups of hunter-gatherers or fishers competed for food or resources and fought to protect their kin. Warfare in this early environment was almost certainly sporadic and brief, albeit potentially deadly, and has influenced behaviours into the modern era.

Cultural anthropologists have also suggested that warfare evolved before the state, both in the remote past and among tribal communities more recently. It was waged by pre-state peoples in a variety of ways – from ritual stand-offs to full-scale massacres – and was, in many cases, reinforced by a prevailing culture that endorsed violence when necessary and prompted the evolution of a warrior class and militaristic values that glorified war.

Evolutionary biologists and psychologists see the emergence of warfare as having occurred much deeper in the human past, when small groups of hunter-gatherers or fishers competed for food or resources and fought to protect their kin

There are many examples of warfare among peoples who lacked state structures but fought from a variety of motives – over resources, land, booty and vengeance. The Māori fought with extreme violence among themselves to protect food supplies stored in special silos known as pa. Tribal chiefdoms in Neolithic Europe fought regular engagements against encroaching tribes or to safeguard trade.

In North America, too, tribal conflict often led to extreme violence. Take the massacre perpetrated in the first millennium AD in southern Utah. The skeletons of 92 victims, mostly male, were found at Wetherill’s Cave, displaying evidence that they had been bludgeoned to death, scalped and decapitated.

What evidence is there for ‘emergent warfare’?

Such bloodletting was not the same as modern organised war, but it is difficult to see the pre-state past as peaceable, given everything we now know about collective, war-like conflict. Evidence for this stage of ‘emergent warfare’ has been found in the archaeological record in the form of weapons, fortifications, iconography and skeletal remains scarred by bone damage indicating violence.

At Talheim in Germany’s Neckar Valley, marks on the excavated remains of 32 men, women and children who lived around 7,000 years ago suggest that they fell victim to attack by axes, clubs and arrowheads. The examination of Paleoamerican skeletons from between 8,000 and 7,000 years ago has revealed that more than half met a violent death.

Why have there always been wars?

Clearly, humans have been fighting each other since long before the emergence of the state. But this fact reveals little about why.

We are far more belligerent than any other species, and have evidently evolved that belligerence as one means of survival in the face of factors such as competition from other humans and ecological shocks. In short, warfare has become completely embedded in the human past.

But wars are not all the same, even if they are rooted in common causes. To make sense of the bewildering number of conflicts in the recorded past, certain recurring motives can be found: the need for resources; the imperatives of belief or ideology; the pursuit of power; and last, but by no means least, the search for security.

Motive for war #1: fighting over resources

The quest for, or protection of, resources has a long pedigree. Whether the aim was to preserve a hunting ground from trespassers, or to claim additional land, or to capture slaves, or to leverage payment of tribute, resource wars are identifiable. In many cases, ecological shifts caused by climatic change, overhunting or population growth have prompted the violent pursuit of resources.

The pressure of nomadic tribes on the northern Chinese frontier 2,000 years ago was driven in part by sudden climate shocks that reduced pasture land. And a prolonged drought in central North America in the late-13th century triggered waves of bloodshed as tribes struggled to find food in an arid land.

In the modern age, the drive to secure resources has been less obviously the primary motive behind acts of war. However, there is one notable exception to this rule: the Second World War. German aggression against the Soviet Union in summer 1941, and Japanese attacks on the US and on the British and Dutch empires later the same year, were unquestionably propelled by a thirst for material resources and land.

“What one does not have, but needs, one must conquer,” announced Adolf Hitler shortly before his troops invaded the Soviet Union in June 1941.

That summer and autumn, he sparred with his generals, insisting – against their instincts – that German forces should first seize the coalfields and other rich assets of the Donbas rather than focusing on the capture of Moscow; their 1942 campaign was also intended to claim the oil and other resources of the southern Soviet Union. These would be needed if Germany were to become an economic superpower capable of holding off or defeating the British empire and the US.

Japan’s leaders also saw resources as vital to their war effort in China and their ambitions to be a major power. It was this imperative that drove their decision to launch the Pacific War. This, they hoped, would provide them with the material resources – the oil and minerals of south-east Asia – necessary to prevail over the western powers.

Motive for war #2: belief and ideology

Religion has also proven a powerful driver of conflict over the centuries. But should it be taken seriously as a cause in its own right? Or does it often, in fact, mask social and economic motives? Historians have debated these questions for centuries – and when they have, the medieval crusades launched by Christian powers against the so-called ‘infidel’ have rarely been far from their minds.

Though some historians have contended that economic gain and local power were the crusading knights’ true goals, it could be argued that this conclusion is a product of the outcome of these campaigns, rather than their cause.

Pope Urban II’s 1095 call for Christians to capture the Holy Land – and, in doing so, to win redemption from sins – was answered by thousands of people, both rich and poor. They overcame unimaginably harsh conditions and succeeded in the capture of Jerusalem in 1099, where they slaughtered the city’s Muslim and Jewish inhabitants.

Only belief made sense of the campaign and the contest to hold onto the new crusader kingdoms in the east. Belief also prompted Islamic leaders to unite in order to drive out the crusaders, with the promise of paradise for those who died fighting for the cause; by the end of the 13th century that campaign was complete.

The call to jihād – war in defence of Islam – has been revived in recent years, with strong echoes of a much earlier rhetoric. Longstanding Iranian supreme leader Ayatollah Ali Khamenei’s recent claim that Jerusalem will again be in Muslim hands echoes the 12th-century campaign to recapture the city from Christian control. Belief, then, is not so easy to dismiss as a cause of war.

Motive for war #3: pursuit of power

On the face of it, the link between war and the pursuit of power appears far less controversial. Few would argue with the contention that the quest for authority and control over others has always been a prime driver of conflict. Yet even this conclusion runs into problems, because people seldom fight for power for its own sake. Rather, conflict aims to gain power for something: seizing land, demanding tribute, controlling resources, enhancing security and satisfying honour.

Military power may be the means to achieve these aims, but it is the instrument rather than the cause. However, there can be little doubt that the desire for power was the motor that propelled some of history’s most famous (or infamous) figures – Alexander the Great, Genghis Khan, Napoleon Bonaparte and Hitler – along the road to conflict and conquest.

Whatever else drove these individuals to wage war, an insatiable appetite for personal power was clearly central. Napoleon was a classic case. Relentlessly driven to rise above the ordinary, he embarked on a military career at a young age. “The only thing to do in this world,” he told his brother Joseph in 1794, at the age of about 25, “is to keep acquiring… power and more power. All the rest is meaningless.”

Power for him was bound up with military success, which meant dominating as much of Europe as he could. And power brought with it a popular cult of Napoleon as saviour and ruler. ‘Saint Napoleon’ or ‘Napoleon the Great’ were epithets wielded to enhance his status.

Napoleon could brook no opposition to his power, which explains the constant conflicts in central Europe, Spain and, eventually, Russia, where his ambition reached its limit. The pursuit of power made possible other achievements, but it was also the sign of a man who didn’t know where to stop. That thirst for power warped Napoleon’s thinking even while he was incarcerated on an Atlantic island. Here, during his final exile on St Helena, the vanquished French emperor claimed that, if he had succeeded in Russia, he would have been “the greatest man that ever lived”.

Motive for war #4: security

Power and religious faith may have sparked numerous conflicts down the centuries, but the quest for security is surely the most common motive in all of recorded history for waging war. Modern security studies were born in the aftermath of the Second World War, and security of all kinds has become something of a modern obsession.

But security as an ambition has a much longer pedigree. English philosopher Thomas Hobbes, writing in the 17th century, saw the defence of frontiers by a permanent “posture of Warre” as essential for security in the absence of a power to enforce peace and the lack of sufficient trust in others.

The anarchic nature of the international order is a major argument for why modern states must stay armed and prepared, even when there are institutional or legal constraints on resort to war, or a strong desire for peace. Linked to this, frontiers or borders have long been flashpoints. Indeed, most wars in the modern age have been fought between neighbours, and very often over issues of security around a frontier.

English philosopher Thomas Hobbes, writing in the 17th century, saw the defence of frontiers by a permanent “posture of Warre” as essential for security

This is true today of the current conflict in Gaza and also of the Russia-Ukraine war, which was launched – or so Russian leaders claim – in order to create a secure frontier against what Moscow sees as the menace to security posed by Nato.

But it was also true of the Roman empire, whose long frontier, though seldom fixed in the way most of today’s borders are, had to be defended against a host of potential enemies to preserve the security of imperial territory. Rome’s frontier was a constant source of friction and war. It stretched over 5,000 miles around western Europe, the Middle East and north Africa, extending from Britain in the north to the Sahara in the south, and from Spain in the west to areas beyond Palestine in the east.

This border was porous, though great efforts were made to install watchtowers or outposts along its length in order to monitor entry and to safeguard against violent incursions. Hadrian’s Wall – the Vallum Aelium – is arguably the best-known example, constructed in an effort to keep the tribes of the Caledonians and Maeatae at arm’s length from the Roman province of Britannia.

The wall was connected by roadways to garrisons farther south, so that reinforcements could be rapidly marched in, and forts and watchtowers were set along its 73-mile length. At least 11 major raids by Celtic tribes were recorded between AD 160 and 400, but the wall served its purpose – preserving the security of the provincial territory.

By the fourth century AD, most Roman soldiers were stationed along the frontiers in Europe, Africa and the Middle East, and the primary endeavour of the empire was frontier security – until it was overwhelmed by the tribal federations driven from Eurasia into the Roman heartland.

War in the 20th and 21st centuries

Some historians assert that, over the 16 centuries since the fall of Rome, the global order has become more peaceable. However, that argument has been thoroughly undermined by the fact that the 20th century witnessed the two largest and deadliest wars in human history.

Indeed, there has not been a single year in the 20th or 21st centuries when a war of some kind – state-on-state war, insurgency and counter-insurgency, civil war or resource war – was not being fought. Warfare is embedded in the way modern states think about their security, and that security seems once again at serious risk in the 2020s, as it was in the 1930s.

Today, war is not just history, and much academic effort has been devoted to assessing what kind of conflicts will emerge over the course of the current century. The concept of Power Transition Theory, developed by international relations experts during the Cold War, suggests that a challenge to a hegemonic power by a rising power creates the danger of war, either to defend a waning hegemony or to elevate the challenger.

It’s proposed that a potential war between China and the US would fit this pattern, though it remains a speculation impossible to predict with certainty.

More likely sources of conflict are the shrinking availability of resources – oil being a key example – and competition for their control. This is being exacerbated by the effects of climatic change, as climate shocks undermine resource availability – notably of water – or precipitate mass migrations in affected regions.

Cyberwar or war in space have also become potential arenas of conflict as militaries have come to rely on sophisticated electronic communication. Over the past 15 years, America has activated US Cyber Command and US Space Force to beef up its defences against new threats – and to enable it to launch counterattacks. These initiatives, and the long history of human belligerence that preceded them, suggests that we shouldn’t anticipate a warless world in anything but the remotest future.

War first emerged in the archaic past, evolving through the stages of village, tribe, tribal federation, state and empire into a universal phenomenon. As to why it did so? Well, there’s no single answer to that – much as Einstein might have wished for one.

**Richard Overy is honorary research professor at the University of Exeter, and author of Why War? (Pelican, 2024)

Ad

This article was first published in the October 2024 issue of BBC History Magazine

Ad

Ad

Loading...

Ad

Loading...