Quantitative history
Sigma
Estimates historical quantities from registers, account books and court records, and turns received causal explanations into rules and simulations to test whether they produce the history they claim to explain.
Estimates historical quantities from registers, account books and court records, and turns received causal explanations into rules and simulations to test whether they produce the history they claim to explain.
Malthus and Turchin each wrote down a mathematical relation governing agrarian society, and our society's founder wrote down another for industrial society. This page sets out what these relations are and how far the Ekumene simulation has tested them: the model reproduces the textbook conclusions, but the process that produces them differs from history in three respects. With a cell-by-cell replay of fifteen hundred years in Mesopotamia.
Sigma · Research in progressWhy the return capital expects has long exceeded economic growth; and how, twice in the two centuries since the Industrial Revolution, capital went first into new technology, then abroad and into land and lending, and each time ended in a clearing. Told with two hundred years of wealth data for the world and for Britain.
Sigma · Research in progressWhat share of their income or output peasants handed over in taxes and dues, and how much went to the state, to lords and to the church, computed for whole villages, districts and provinces from the original registers.
Sigma · PaperA world simulation run from scratch, stepped period by period to watch territory, population and taxation change.
Sigma · Data and toolsThe third version of the same world simulation, run from 4000 BC to AD 1500. The page explains why this version corrected the billions of people the first two versions produced.
Sigma · Data and toolsThe earliest public viewer of the simulation: the world split into eighteen regions, played period by period from 1000 BCE across twenty-five data layers, comparing the number of polities and the population of China and Europe.
Sigma · Data and toolsWhether the London bond market sensed, before war broke out in July 1914, that war was coming.
Sigma · PaperHistorical explanations often say that some condition brought about some outcome, but history happens only once and there is no control group. This project builds a world simulation driven by mechanisms of population, food, money and war, runs it again and again from the same starting point with perturbations, and sees whether the outcome is the same each time or diverges, as a way of testing whether claims that an outcome was inevitable hold up.
Before war broke out in July 1914, did the London bond market sense that war was coming? British and Russian government bond prices, as printed day by day in The Economist, are converted into the probability of war implied by the market; over the same period a language model that has read only pre-war texts gives its own probability, and the two curves are set side by side to see which rises first and by how much.
Before a political crisis breaks out, those involved can seldom tell whether it will escalate into war; afterwards, historians often say the outcome was all but unavoidable. This project pairs crises by the conditions said to drive escalation, such as military strength, alliances and geography, to see whether the share that actually escalated to war is markedly higher; it then has a language model that has read only texts from before the starting point act as an observer after the fact, judging how hard the outcome was to avoid, and compares that judgment with the real spread obtained by simulating the same starting point thirty times, to see whether it underestimates how far history could have diverged.
What share of their income or output peasants handed over in taxes and dues, and how much went to the state, to lords and to the church, computed for whole villages, districts and provinces from the original registers.