『Capital in the Twenty-First Century』要約

Thomas Piketty's Capital in the Twenty-First Century, first published in French in 2013 and in English in 2014, argues that capitalism has an inherent tendency toward rising inequality when the rate of return on capital (r) exceeds the rate of economic growth (g). Piketty, a French economist, builds this claim on two centuries of tax, inheritance, and wealth data assembled with collaborators including Emmanuel Saez and Gabriel Zucman, forming a dataset unprecedented in its historical reach. The book's central framework distinguishes income from wealth, noting that concentrated capital compounds faster than wages or output, so inherited fortunes regain the dominance they held in nineteenth-century Europe—the world of Balzac and Jane Austen, whose novels Piketty reads as evidence of a society where marriage mattered more than merit. He traces this dynamic through the Belle Époque, its disruption by the two world wars and the Great Depression, and the postwar decades when high taxes and fast growth temporarily compressed inequality, before the trend reversed after roughly 1980. Piketty proposes a global progressive tax on wealth and steep top marginal income tax rates to check this drift, acknowledging such coordination is politically difficult. He also examines the United States separately, arguing its frontier myth and mid-century "patrimonial middle class" masked a trajectory since 1980 toward oligarchic wealth concentration reminiscent of old Europe. The book draws on literary sources, national accounts, and estate records rather than formal mathematical models, and its data appendices, revised in later editions, became a subject of vigorous scholarly debate.