My friend Tarik sent me the chart above pursuant to an unrelated thought experiment. It comes from the Economist, which compiled figures from little-e economist Angus Maddison and the UN to plot economic output and percentage of total human-years lived against centuries. A human-year is a particularly useful unit of history if you prefer the broad trend hypothesis to the Great Man Theory. As the Economist puts it, “if people do make history, as this democratic view suggests, then two people make twice as much history as one.” Fact: two people, each living 70 years, experience more human time—that is, history—than one person living 70 years. Given that the life expectancy of your typical eighth-century serf was like 28, the lion’s share of human experience has taken place in the last century.