Until the late 20th century, most philosophical
discussions of justice and equality were limited in scope to a single society.
Even Rawls’s theory of justice, for example, had nothing to say about the
distribution of wealth between societies. In the 1990s philosophers began to
think about the moral implications of the vast inequality in wealth between the
leading industrialized countries and the countries of the developing world,
some of which were afflicted with widespread famine and disease. The
German-born philosopher Thomas Pogge argued that affluent countries are
responsible for increasing the poverty of developing countries and thus for
causing millions of deaths annually.