uman inequality is commonly described by its defenders as a discovery, but we can allow ourselves to think that it, indeed, is socially constructed. Many different kinds of inequality appear in human history, and each one must be overcome if humanity and equality are to triumph in the practical as well as the ideological world. We have to deal with geographic inequality (the barbarians on the other side of the border), racial inequality (whites or Chinese and the inferior “others”), hierarchical inequality (masters and slaves, aristocrats and commoners), and economic inequality (the rich, the poor, and the desperately poor). These four inequalities are very old and ever-renewed; we know them well. Siep Stuurman adds a fifth to this list, which he thinks is peculiarly modern: temporal inequality. “We” are advanced, and “they” are backward.