In 1917 the poet Edward Thomas was asked why, at the age of 37, he had enlisted. He knelt down, scooped up a handful of English soil and replied ‘literally, for this’. The defence of territory is the oldest cause of war but, by the 20th century, it had gone ideational. In his book Where Poppies Blow, John Lewis-Stempel contrasts the love of the English countryside with the German preoccupation with dark, gloomy forests. Blood and Soil (Blut und Boden) was a prevailing theme of German nationalism in the late 19th and early 20th centuries. What does this caricature of the Germans remind you of? Perhaps, The Lord of the Rings and the Orcs. And of course, Tolkien, who fought in the First World War and was traumatised by the experience, conjures up in his epic tale the peaceful shires, the land of the lovable and very English hobbits, which is contrasted with the industrial wasteland of the highly unlovable Orcs.

When I was invited to write this essay, I immediately thought of the work of the Dutch ethologist Nikolaas Tinbergen, who was awarded the Nobel Prize in Physiology in 1973. He drew up a framework for understanding animal behaviour and encouraged us to ask four questions that I feel are highly relevant to war:

1. What are its origins: how did it first arise?
2. What are the mechanisms which allow it to flourish?
3. What is its ontogeny: its historical evolution across time?
4. And what is its function: its adaptive significance (ie the role of behaviour in facilitating reproductive success)?

These are the questions that every phenomenologist of war should ask and all four are contained in Edward Thomas’s response. The soil is almost certainly the main reason why we are an aggressive species (as are most others). The territorial imperative is the dynamic of life. Then there is the mechanism of the imagination. Thomas subscribed to a national myth that arose in part from early 19th-century Romanticism. Like so many members of his generation he joined up, like the traumatised war veteran of Virginia Woolf’s novel, Mrs Dalloway, ‘to save an England which consisted entirely of Shakespeare’s plays’. As for ontogeny, the countries that went to war in 1914 were nation states, or nation states in the making. England was the very first. And as for its functions, war fuelled itself – Thomas was imprisoned by his own narrative, which is different from saying that the narrative produced the Great War. But it certainly prolonged it.

At the same time as Thomas Hobbes was painting what Steven Pinker and others consider to be a true picture of our distant past – the state of nature – a contemporary of his, a country parson named John Frere, developed a hypothesis, based on the evidence of ancient flints, that we had been in the war business from the very beginning. And there is evidence that we are not the only hominid species to have invented war: the very first tools used up to 2.6 million years ago were quite possibly weapons – take the painstaking modification of fine-grained igneous rocks into sharp-edged forms that could carve into the flesh and bone not only of other animals, but members of our own species. Read the work of Timothy Taylor, Professor of the Prehistory of Humanity at Vienna University. The point is that territory and its defence is almost certainly the origin of war: the need to defend scarce resources and guarantee the food supply. But the point is that territorial behaviour evolves in every animal species only when an economic resource is economically defensible: when the energy saved in territorial defence outweighs the energy expended in the risk of injury and death in defending it, as the Harvard biologist Edward O Wilson asserted in On Human Nature.

Historians of course are still divided as to whether war – as we understand the term today – dates only from the invention of agriculture, when we had much more to defend, or the emergence of chiefdoms. Chiefdoms are typically agricultural societies, much bigger and more elaborate than the average hunter-gatherer society, and they have been found by archaeologists, notably, in the vicinity of ancient civilisations. They can be regarded as an intermediary form of social organisation on the way to the creation of the state. But there is an additional factor in play. Montesquieu famously proposed that war began not from ordinary aggression or occasional marauding but when the weak defender hit upon the idea of organised resistance. But if you can organise the defence of your own territory, you can also organise a raid on someone else’s. ‘How do we organise the Defense Department for manhunts,’ Donald Rumsfeld asked at the beginning of the war on terror; and some see drone warfare as man-hunting on a grand scale. It’s a profession that now has its own technocratic jargon, derived in part from social network analysis and Nexus topography, a pseudoscience which enables us to map social forms or the environments that bind individuals together and thus define – and take out – the critical nodes in a network (in this case terrorists). Aristotle got there first: in the Politics, we read that there are five main ways by which men live by their labour, and he included war – the simultaneous hunting of people and possessions. The Greeks were not squeamish when it came to spelling out reality.

So much for the origins of war, but what of its mechanisms: the things that fuel it. Literature is one. Here is a line from Edward O Wilson about the world’s two dominant species, this time in a work of fiction: ‘I sing of ants and the man.’ In Anthill: a novel, Wilson is of course echoing the opening lines of Virgil’s epic poem, the Aeneid: ‘I sing of arms and the man.’ But ants don’t really lend themselves to epic poetry, do they? And even if you’re a sociobiologist like Wilson, the fact that we have poetry and they don’t surely makes all the difference? Since Darwin, we have been asking ourselves whether war is more genetic or cultural; is it located in our genes, or in our cultural DNA? Culture would appear to be the key; we have it, ants don’t. For which we and they must be thankful. We may be a highly social species, but we can be very unsociable indeed, particularly when the tribe with which we identify seems to be under threat. Ants may well outlive us precisely because they don’t have the benefit of civilisation. Without it, for example, you can’t build a nuclear bomb. If we do destroy ourselves in a nuclear war, ants will almost certainly survive into the post-Anthropocene age. Yet we may rest assured that, even after our disappearance, there will not be ant archaeologists sifting through the rubble of our long-compacted cities.

But back to Virgil. Literature has an especially adaptive function – it provides us with role models and inspiring tales of heroism that tell us there is a life out there to be lived in a higher emotional register that we can’t often find in times of peace. War embodies, if you like, a loose assemblage of algorithms or programs for collective action. The idea that it is glorious to die for one’s country has persisted for centuries. In that respect, argues Barbara Ehrenreich, war is contagious. Culture cannot always be counted upon to be on our side. In Blood Rites, Ehrenreich wrote: ‘In so far as it allows humans to escape the imperatives of biology, it may do so only to entrap in what are often crueller imperatives of its own.’ What Virgil succeeded in doing was turning a territorial imperative into patriotism; indeed, the Aeneid shows patriotism before it degenerated into nationalism. Patriotism in the poem becomes pietas. One meaning of the word is ‘piety’. Another is ‘familial’ – a fierce commitment to family. But a third meaning is ‘loyal’ – loyal to friends, to the extended family, the ‘band of brothers’ – the other family that soldiers celebrate and which they so often miss on their return from battle. Literature and art are two of the mechanisms that inspire us to turn death into sacrifice. The word is derived from the Latin for ‘sacred’. Going beyond its etymology, the Hebrew tradition suggests that suffering can be redemptive. The state becomes a sacred community and its defence a religious duty. It is by accepting the need for sacrifice that many live a sacred life and find meaning in the otherwise meaningless lives they lead. Roger Scruton put it well in an article for Prospect magazine in April, 2000, ‘Desecrating Wagner’, when he wrote: ‘Seeing things that way, we recognise that we are not condemned by mortality but consecrated by it.’

And so to my third question: war’s ontogeny, its development over time. The defence of territory is usually the defence of the state. States have been around for the last 5000 years and come in many forms. In On Human Nature, Wilson places much emphasis on the concept of hypertrophy: the extensive development of a pre-existing structure. The similarities between states pre-modern and modern, agricultural and industrial, are as striking as the many variations. They merely become more complex over time. States are an example of what sociologists call a ‘thick’ institution, with collective rituals, sacred stories, heroes who rescue it from the brink of disaster; initiation rituals; flags and symbols; even different emotional registers and moral ecologies, and of course language that keeps outsiders in their proper place – namely outside. Think of nationalism as merely a particularly vivid example of a culturally marked outgrowth of tribalism.

But defence of territory can extend well beyond traditional borders – take the remarkable commitment of the early Crusaders. The recovery of the Holy Land was the defence of a wider Christian community. The supranational nature of the Crusades was one of its distinctive features. Love of Eastern Christians in the territories occupied by Muslims was a chief motivating factor in deciding to join up. It was of course a one-dimensional view of the world – there was no echo here of Christ’s injunction to love one’s enemy, still less of St Augustine’s insistence that it was more virtuous to love one’s enemies than one’s friends. Love of one’s neighbours meant largely love of one’s fellow kinsmen. The crusaders were animated by the idea of the wider family at risk. In this respect, writes Jonathan Riley-Smith in The Crusades: a short history (1980), the Crusades can be seen as essentially a blood feud between two rival families, and blood feuds are usually geographically delimited.

Fast forward to the First World War and Willa Cather’s Pulitzer prize-winning novel of 1926, One of Ours, an extraordinary tale of a young American who joins up in 1917 to defend France. What he finds is what a fellow and very real American, Alan Seeger, who joined the French Foreign Legion and lost his life at the Somme in 1916, called ‘that rare privilege of dying well’. Cather’s novel was trashed at the time by Hemingway, who thought that women couldn’t write about war. Hemingway himself claimed to be the first American to be wounded in Italy. In fact, he was the second, but unlike the first, he survived his wounds. Or did he? For his life was a mess after the war: three failed marriages, two messed up children, one self-shooting (besides the fatal one) and, above all, a career that he regarded as a failure. But he too created in Robert Jordan, the hero of his novel For Whom the Bell Tolls, a man who came to Europe to fight for the Spanish democrats against the fascists. And in Cather’s novel, the young Nebraskan is happy to defend France – for him, the cradle of modern Western civilisation – against the Barbarians, the Huns, the Orcs. One of Ours is not an anti-war novel, far from it. It celebrates the willingness of a young man to sacrifice himself for an extended family; or in this case, to quote Charles de Gaulle, for a certain ‘idea of France’ – la France profonde.

And so to the fourth and last category: the function of war. The function of war is to serve itself; it imprisons us in the stories that we overhear ourselves telling. One particularly powerful story that Jihadists tell themselves is about the ‘once and future’ caliphate, virtual in the case of Osama bin Laden, physical and very real in the case of ISIS (which is why Western politicians are so terrified of calling it Islamic State). For ISIS, violence is functional; it works, which is why we find it so threatening. In A Theory of Religion (1987), Rodney Stark, a sociologist of religion, pointed out that the more demanding a religion is, the more value it has for the devout because of the sacrifices that must be made, and that they think worth making. Suicide bombers are like moths attracted to the flame. Their actions are good for religion and good for the group. Martyrdom, as William James argued in his book, The Varieties of Religious Experience, is one of the ‘religious appetites’ that make the brand so appealing. They are good for the group in the same way that nucleated cells evolve into symbiotic communities of bacterial cells. And a small cult becomes a global brand by suppressing selection within groups, making it difficult for selfish elements to evolve at the expense of other members of their own group. The concept is called ‘major transition’ – the ability to acquire and socially transmit behaviour at the same time.

Evolutionary theory provides a powerful framework for studying terrorism and war, as it does for religion. And all religions invoke the spirit of place: the ancestral land, the promised land, Jerusalem, the city on the hill, the new Eden, the caliphate. And the nationalism of Edward Thomas, seen by some historians as a political religion, was as intense as a religious experience. Today it is difficult to convey that intensity of national feeling. We are so distant from the generation that fought on the Somme. But you will find something of its essence in the finest British novel to come out of the First World War, Frederic Manning’s Her Privates We, which tells a strikingly different story from that related by the trench war poets – the Australian-born Manning wrote of the stoicism of British soldiers, not their heroism. But of course their stoicism is precisely what was heroic about their unwavering commitment to their country, to the very end. In the military parlance of the time, they ‘answered the call’. They did so for the most part uncomplainingly; they took great pride in ‘coming through’ for each other, even if this much reduced their chances of coming back.

Let me end on another note, however: the extent to which the warriors of the future may be disengaged, or distanced, literally and figuratively, both from territory and from war itself. We still read the great ‘homicidal narratives’ like the Iliad (the phrase is Tom Stoppard’s), where warriors get close to the kill. The future, however, may well belong to warriors like Vollmer (he has no first name), a character depicted by Don DeLillo in his short story, Human Moments in World War III, originally published in 1983. Vollmer is a member of an orbital space capsule who spends his days surveying a world in which nuclear weapons have been banned, with the result that the world is permanently at war. Pilots enjoy all the creature comforts: video cassettes and piped music. They can wear their carpet slippers at their firing panels as they zap terrorists with laser weapons. From the vantage of space, our young pilot’s patriotism is not to country but the Earth. Occasionally, the Earth’s orbit will put him in a philosophical temper: he has a privileged vista, after all. But he has come to see the Earth rather differently over time. He once saw it in the same way that Edward Thomas saw his own country, in terms of the romantic imagination. He used to see it as ‘storm-spirited, sea-bright, breathing heated haze and colour’, but over time he has become disengaged. We find him, at the end of the tale, looking out of the window, eating almond crunches, as the wrappers float away in zero-gravity. He is so detached that he can no longer empathise with the planet. What he likes most about it, or rather, to use his own words, what he finds most ‘interesting’, are ‘the colours and all’. On that note, he fades out of view.

This essay was originally published under the title Dying for Territory in Nation, State and Empire: Perspectives from the Engelsberg Seminar, Axess Publishing, 2017.