It is​ by now common knowledge that income inequality has grown by leaps and bounds as a result of the neoliberal policies of the past half-century. The United States is a case in point – eight hyper-rich Americans today own as much as the entire bottom half of the nation’s households – but it is not an anomaly. Such massive inequalities are a global phenomenon. In 2015, Walter Scheidel writes in The Great Leveller: Violence and the History of Inequality from the Stone Age to the 21st Century, ‘the richest 62 persons on the planet owned as much private net wealth as the poorer half of humanity, more than 3.5 billion people.’ The disparity is stupefying; it would be hardly less stupefying if Scheidel were off by a factor of, say, two or three, and 124 or 186 individuals had as much wealth as the poorest half of the world’s population.

That the rich have grown both absolutely and comparatively richer in recent decades has been evidenced in great statistical detail by Thomas Piketty in Capital in the 21st Century. While the two world wars and the world depression of the first half of the 20th century entailed a massive destruction of accumulated wealth which, however catastrophic, did reduce inequality, the postwar peace has restored the advantage of the very wealthy. The perverse price of peace, Piketty finds, is that in peacetime the return to capital (interest, dividends and profits) routinely exceeds the rate of economic growth (and therefore of income growth). Year by year, as long as this apparently invariable relationship holds, mounting inequalities in income distribution are inevitable. Piketty, like the good social democrat he is, has any number of suggestions for state policies that would interrupt this logic, or at least mitigate it. He proposes a global tax on wealth and believes that a top income tax rate of 80 per cent would be optimal. He recognises that such policies stand little chance of being enacted, let alone enforced, but that doesn’t stop him exploring the ways in which state policy might redistribute income with a view to improving the life chances and wellbeing of the poorest.

No such optimism, however far-fetched, is allowed to enter the dark precincts of Scheidel’s deep history of inequality and its remedies. He leaves no doubt that ever since the origin of farming – and hence of landed property – the default setting of economic evolution has been growing inequality. The book’s quantitative bulldozing and vast temporal and geographical reach are designed to substantiate two seemingly straightforward propositions: first, that technological and economic development, abetted by state-formation, are the chief drivers of ever growing inequality; second, that ‘effective levelling required violent shocks that at least temporarily curtailed and reversed the disequalising consequences of capital investment, commercialisation, and the exercise of political, military and ideological power by predatory elites and their associates.’

Periods of lessened inequality, Scheidel aims to show, have rarely, if ever, been the result of a simple improvement in the income of the poorest sectors of a population. Instead, they have been the result of a near cataclysmic destruction of the accumulated wealth of privileged elites, often accompanied by the deaths of large numbers of people, poor and rich alike. Levelling is not the result of a policy to redistribute wealth and life chances, but the unforeseen consequence of social and economic disaster. The poorer half of the population may end up, after a war or a plague, with a larger relative share of the national income and wealth, but only at the cost of surviving a catastrophe. It seems that the only satisfaction they stand to gain from such levelling events is the thin gruel of Schadenfreude.

What Scheidel calls the ‘Big Reasons’ for levelling ‘shared one common root: massive and violent disruptions of the established order. Across recorded history, the periodic compressions of inequality brought about by mass mobilisation warfare, transformative revolution, state failure and pandemics have invariably dwarfed any known instances of equalisation by entirely peaceful means.’ Scheidel means to insist on the massiveness and violence of these disruptions; nothing less will do. Dürer’s Four Horsemen of the Apocalypse illustrates the book’s cover. His examples of ‘mass mobilisation warfare’ are the world wars of the 20th century and the US Civil War (particularly on the Confederate side); ‘transformative revolutions’ are represented by the Bolshevik and Chinese communist revolutions; and ‘pandemics’ principally by the Black Death of the 14th century. ‘State failure’ – Scheidel sometimes calls it ‘systems collapse’ – is somewhat more sketchily represented by the sudden and still mysterious disappearance in the 11th century bce of the palatial Mycenaean kingdoms of the Mediterranean, the break-up of the Roman Empire in the fifth century ce, and contemporary Somalia.

Scheidel’s analysis of the world wars and global depression of the first half of the 20th century forms a close parallel to Piketty’s account of how these catastrophes ‘compressed’ income distribution. In this period, where the data are abundant and unambiguous, Piketty is the surer guide to the statistics and the dynamics of compression. Scheidel’s ambition is to extend the analysis back as far as the Stone Age. For ancient societies, the data bearing on income distribution is sparse at best, and sometimes bogus. Scheidel is fully aware of the interpretative caution required. He edges his way into the fog by making cautious inferences from such suggestive data as dowries, rents, inventories of household goods and the differences in ‘grave goods’ between commoners and elites. Where the data do not permit reliable conclusions, he prudently retreats.

‘Transformative revolutions’ are the only kind of levelling event in which deliberate human agency is, at least in principle, involved in trying to increase economic equality, but even here Scheidel insists that it is only, and specifically, the violence involved in such revolutions that causes the levelling. In both the Russian and Chinese revolutions, the violence of civil war – of forced collectivisation leading to the gulag or, in the Chinese case, the man-made famine of the Great Leap Forward – was what made the difference. These two revolutions, taken together, caused roughly a hundred million deaths and were, as Scheidel sees it, equivalent to the two world wars in their violence and levelling effects. The French Revolution, by contrast, was far less bloody and its egalitarian effects were both modest and short-lived.

If the French Revolution failed to usher in a new egalitarian order, in spite of the Terror and the flight of the aristocracy, it is perhaps unsurprising that social democrats, Fabian socialists, ‘land to the tiller’ reformists or today’s advocates of a ‘guaranteed basic income’ have been even less effective in substantially redistributing income. Even the socialist high tide in Western Europe following each world war was, Scheidel argues, largely a by-product of mass mobilisation warfare, which is the single most powerful equalising force in modern history. In a long-term perspective, the category of ‘transformative revolution’ may even be collapsed into ‘mass mobilisation warfare’: to take his examples, the Bolshevik and Chinese revolutions were products, respectively, of the First and Second World Wars.

How does mass mobilisation warfare work its egalitarian magic? Above all, through the massive destruction of property, fixed capital and, of course, lives. It is only the total warfare characteristic of the modern era that resembles a collective auto-da-fé. War alone is not enough. Much traditional warfare comes under Max Weber’s category of ‘booty capitalism’ and was not terribly sanguinary, especially when the loot included captives destined for slavery. Wars of predation might shift the losers’ assets to the victors but were unlikely to change the overall profile of inequality. Total wars, by contrast, are typically fought by able-bodied conscripts and involve the mobilisation of the whole civilian population and economy. Enlisting all the nation’s assets in a war of attrition means, not least, plundering the assets of those who hold most of them: the rich. Income and inheritance tax rates for the belligerents skyrocketed in both world wars. In the First World War the tax on ‘excess’ war profits was 63 per cent in the United Kingdom and 80 per cent in France, Canada and the United States. Material inequality has also been dramatically reduced by the hyperinflation that has frequently accompanied wars and eroded financial assets. In 1918 the Labour Party manifesto called for the ‘conscription of wealth’ to accompany the conscription of soldiers.

Scheidel’s statistics do not take into account the incalculable blood tax of conscription. A democratic ethos requires that when it comes – perhaps before all else – to the chance of dying on the battlefield, every citizen should be treated equally. By extension, it is intolerable that some should profit directly or indirectly from the deaths of their fellow citizens. Total warfare requires an exceptional measure of patriotism, the maintenance of which depends on the mass conviction that everyone is being treated fairly. In other words, the levelling effects of total warfare aren’t simply the result of the state’s squeezing the whole of society for every last drop of work, cash and blood; they are also a consequence of the equalising passions that moments of great sacrifice arouse in the population.

The statistical tool​ on which Scheidel relies most heavily in his analysis of historical inequality is the Gini coefficient, the most widely used measure of relative income share in a given population. The coefficient varies on a scale of 0 to 1, with 0 representing perfect equality of all incomes and 1 perfect inequality. In reality a coefficient of 1 is hardly plausible as it would imply the immanent starvation of everyone except the ‘chief’. Currently Lesotho (0.63) ranks as the most unequal country, and Finland (0.21) – no surprise – the most equal. Most countries cluster between 0.31 (the EU as a whole) and 0.46 (Togo, China, Malaysia and South Sudan).

The Gini coefficient has been calculated or estimated for virtually every nation-state and is the standard measure of income inequality used by such bodies as the World Bank, the United Nations and the OECD. Yet it is statistically peculiar and frequently misleading. Scheidel recognises but by and large ignores the perverse outcomes Gini calculations can produce. For example, a hypothetical country in which one person was in possession of half of the society’s total income and everyone else’s income was precisely the same would have a Gini coefficient of 0.50, very close to the figures for Brazil and Zimbabwe. And what are we to conclude from the fact that the UK and Bangladesh have near identical Gini coefficients (0.32)? Clearly the measure can mask enormous differences in the actual distribution of income.

What’s more, the socioeconomic meaning of a given coefficient can vary wildly between high-income countries and poor ones. In a poor country with an income per capita that is only twice the basic subsistence wage, the maximum plausible Gini coefficient, if the poor aren’t to starve, is 0.50. For a much richer society with a per capita income that is, say, ten or twelve times the subsistence minimum, a much higher Gini coefficient – greater inequality – need not imply absolute deprivation among the poorest. And, most perverse of all, if a war or an epidemic suddenly kills off the poorest quarter of a country’s population, the result will be a lower Gini coefficient, improving the country’s standing in the league tables. Had Jonathan Swift’s ‘Modest Proposal’ for dealing with the excess population of Ireland been realised it would have greatly improved Ireland’s Gini coefficient.

What might we want to know that Scheidel’s analysis can’t tell us? For one thing, it seems vital to know how close to a bare subsistence – and therefore how vulnerable – the poorest sectors of the population are. How volatile are their incomes, and what are the rates of upward (and downward) mobility? Is it a matter, as the Chinese saying has it, of ‘clogs to clogs in three generations’? The tracking of Gini coefficients alone cannot answer these questions. Where the data permit, Scheidel does estimate what portion of a society’s income is monopolised by the top 1 per cent or the top 0.1 per cent. But the problem here is that much of the income of the super-rich is squirrelled away in shell companies and tax havens. Were we obliged to rely on one, and only one, statistic, I would prefer to know the relative income shares over time of the top 20 per cent and the bottom 20 per cent.

Scheidel has chosen not only to lash himself to the mast of the Gini coefficient, but also largely to restrict himself to the data gathered by record-keeping societies – i.e. states and empires. Absent from consideration, therefore, are the thinly scattered but huge populations that existed outside the grasp of the state until at least the 17th century. Many had removed themselves from zones of state control precisely because of the inequalities and oppression they experienced there. Absent too are movements of population from one jurisdiction to another. The huge migrations of the 19th and early 20th centuries from Europe to the New World, for example, surely had the effect of increasing equality in the Old World, not to mention easing revolutionary pressure from below.

Slaves are another glaring absence. Scheidel looks to classical Athens for an early example of mass mobilisation warfare and its egalitarian consequences, attributing its victories against the Persians and against Sparta to progressive taxation and the substantial class of hoplites available to bear arms. He quotes one ‘guesstimate’ of a Gini coefficient for Athens in this period of 0.38. What happens, though, if we include the slave population of roughly eighty thousand in Athens and in its silver mines and quarries, a total roughly equal to the entire population of male citizens? These were essential members of society, but if they were included in calculations for sixth-century Athens, its Gini coefficient would explode. The same is true of early imperial Rome, where slaves made up roughly a third of the population yet are absent from Scheidel’s calculations. Slaves do make an appearance in his examination of the antebellum South, but only as property included in the assessment of wealth, not as part of the population. (Slaves, in 1860, represented more than half the population of South Carolina and Mississippi and roughly a third of the Confederacy as a whole.) Leaving slaves out of the picture does wonders for the Gini coefficient of slave-holding societies.

Scheidel means his analysis to be a counsel of despair. ‘Thousands of years of history boil down to a simple truth,’ he writes. ‘Ever since the dawn of civilisation, ongoing advances in economic capacity and state-building favoured growing inequality but did little if anything to bring it under control.’ He implies that inequality in the economic sphere produces, other things being equal, a political advantage that can perpetuate the position of the elite by means of taxes, business regulations and labour laws. Inequality, in other words, leads to oligarchy, which in turn reproduces and exacerbates inequality. Landed property (i.e. agriculture) and the formation of states are the original drivers of this dynamic: ‘state collapse’ is one of Scheidel’s ‘catastrophic’ equalising events.

One by one Scheidel dismisses the non-catastrophic alternatives that have been the focus of virtually every peaceful movement for social justice: democracy, the extension of the franchise, education, economic growth, social democracy, trade unionism and the welfare state. Their effects, he demonstrates, have been comparatively trivial and have never compensated for the inexorable march of inequality. Like Piketty, he argues that the last fifty years of peace and economic growth have seen a resumption of the cumulative inequality that characterises all ‘normal’ eras. ‘In the absence of violent shocks,’ he writes, ‘we might now be looking back at 150 years of uninterrupted and truly global economic integration, coupled with belated or perhaps still incomplete decolonisation and attendant windfalls for elites in both core and periphery.’ Catastrophe or mammoth inequalities: take your pick.

Realising, perhaps, the limitations of the Gini coefficient, Scheidel briefly explores the Inequality Possibility Frontier (IPF), a measure of the degree to which an elite extracts all that can be extracted from the rest of a population. We might call it the ‘efficiency of exploitation’ index. It is based on an estimate of what ‘maximum’ (100 per cent) extraction might look like in a given society. For ancient societies this might mean driving much of the population to the edge of subsistence; for a more modern society minimum subsistence might include some vital cultural decencies. (A wooden coffin? A small funeral feast? Fish and chips? A birthday party or the means to practise regular religious observance?) The highest rates of extraction by elites are found, Scheidel claims, in conquest and colonial settings, where predation and extraction from a subjugated population are the nature of the enterprise.

The IPF, blind quantitative metric though it is, does at least begin to take account of the fact that it is difficult to say anything meaningful about relative income without understanding that poverty isn’t just about cash and calories. It cannot be treated separately from its cultural context: traditions of housing, cuisine, hospitality, dress, ceremony, celebration, rites of passage, rituals of birth and death, all of which, even in the poorest societies, require resources beyond bare subsistence. We are required, having recognised that there are such social and cultural necessities, to ask not merely what is extracted from a population, but what is available to them (their disposable income after taxes and transfers) and whether what they have affords them the minimum human and cultural decencies that characterise their society. In any contemporary developed society, that would include good enough food and shelter, basic education, medicine and health services etc. The Scandinavian welfare states owe their stability less to their admirably low Gini coefficients than to the fact that they provide even the poorest with the resources necessary to maintain their dignity.