Halfway up the high street in Totnes, a small town on the river Dart in Devon, a modest stone is set into the edge of the road. It claims to mark the point at which Brutus, legendary founder of Britain, first set foot on this island. The grandson of the equally legendary Trojan hero Aeneas, Brutus was said to have been born in Rome; but, exiled from his birthplace, he travelled western Europe before finally settling here.

That the legend of Brutus was a ninth-century fantasy concocted by a Welsh monk named Nennius need not concern us. For Sam Miller, the point isn’t that Brutus was the first Briton, it is that he was a migrant, and his story ‘is another reminder of how normal it once was to eulogise rather than deny one’s migrant past’.

Humans have always sought origin stories. Some peoples have imagined themselves to be wholly indigenous. ‘We Athenians are the only Greeks who never migrated,’ Herodotus has an envoy say. The Taino people, whom Columbus encountered on Hispaniola in 1492, believed they emerged from two caves on the island. But settlement and deep-rooted continuities are only one part of the human story. Migrants, Miller’s enjoyable, provocative and timely new book, aims to show us our history ‘through a prism in which migration is a normal activity’. It challenges what Miller calls ‘the myth of sedentarism’, the idea that human beings are by nature settlers, inclined to live and die in the same place among the safe, familiar and known.

Sedentarism began around 12,000 years ago in the Middle East. Those who settled quickly regarded themselves as superior to those who did not. ‘Pure are the cities – and you are the ones to whom they are allotted,’ a story about the Mesopotamian water god Enki begins. Before that, we were all nomads. It is part of our nature, Miller argues. No other land mammal has spread so far across the planet, with the possible exception of the rat. As recently as 400 years ago, a third of the world’s population was still nomadic. Most of us carry with us a little Neanderthal DNA. We are all mongrels of a sort.

Humans settled, but they kept one eye on the horizon. We don’t tend to think of ancient Greece as an expansive world, yet Greek city states established at least 270 new settlements around the Mediterranean and the Black Sea. Miletus alone founded 36. In France, Marseille is still sometimes known as La Cité Phocéene after its founders from Phocaea, now the Turkish coastal town of Foça. The arrival of the Greeks was a mixed blessing for existing populations; in Syracuse, for example, they were enslaved. It is thought that Alexander the Great planned to forcibly transplant populations from Asia to Europe and vice versa to help unify his empire, but died too young to implement the scheme.

Outside of the Americas, Miller tends to downplay the impact of mobile populations on resident ones. The Vikings were more peaceable than we were once taught; the Vandals looted Rome in 455, but they didn’t vandalise anything. He returns several times to the idea of migration as an ‘adventure’. He cites former migrants across the Mexican-US border – so-called wetbacks and braveros – who use just that word about their youthful journeys.

But Alexander’s plan highlights a recurrent problem. Miller wants to argue that migration is not only a quintessential human activity, but a human good. The inclusion of forced migrations complicates that argument. The most obviously troubling example here is the transatlantic slave trade. How can it be migration if there is no element of choice, a friend challenges him. Miller’s defence is that enslaved people still retained some residual free will. ‘Suicide can be an act of rebellion,’ he writes. It will not persuade everyone.

Perhaps the most serious omission, meanwhile, is nomadism. The topic receives a few paragraphs, but in a book which wishes to argue that human mobility is a virtue and a purpose in itself, the absence of the Roma and other itinerant peoples is surprising. They would seem ideal exemplars of the mobile life which Miller extols.

He himself is a much-travelled former BBC journalist. He lived in Delhi for more than a decade and has subsequently lived and worked for long periods in numerous countries across Asia and Africa. The book’s thesis derives in part from his own experiences, and the more personal, discursive passages are among its most compelling.

Migrants raises profound questions about how we order and police the world. Miller makes an eloquent case for migration as essential to what it is to be human. Is it a human good, though? Perhaps. But not for nothing was our exile from Eden a punishment.