Development of the "Third World" is usually thought to be an idea that emerged in the 1950s as colonialism was ending. But the development idea emerged centuries earlier. Thinkers in the West had formulated a Development Right of Conquest, in which the West justified itself taking lands in the Rest because it offered higher material income to the people on those lands.
Liberal thinkers questioned whether higher material income really improved well-being when people did not have the right to consent to their own progress. Economists from Adam Smith to Milton Friedman and Amartya Sen advocated commerce as a voluntary alternative to conquest.
Liberal ideas eventually registered tremendous victories: the abolition of slavery, the end of colonialism, the decline of Communism, and the surge of trade between the West and the Rest.
