Poverty persists, essentially, because the people at the bottom - the bottom quarter and also the bottom half - see the gains from the rising global average income wiped out by severe declines in their relative share.

In 88 poor countries for which we have data, in each and every one of the 88, the PPP for food shows that poor people can buy less food than you would expect from the PPP that the World Bank is using. The reason for this is obvious on reflection. It has to do with the fact that most foodstuffs are tradable commodities: basic foodstuffs, such as rice, flour and beans, can easily be conveyed across national borders and their prices will therefore roughly mirror the exchange rates among currencies.

What is really nice about the Health Impact Fund is that it is a win-win, something that without much cost to anyone makes a lot of people better off.

Income inequality matters more on a day-to-day basis. Wealth matters more for political influence.

It is perfectly consistent - and also true - to say that the world poverty problem today is smaller (relative to world population) than before and yet also a much graver injustice.

Feudalism is an economic system where a few people own all the land and the others have no option but to be serfs on such a feudal estate. We now condemn feudalism. We condemn not merely the feudal lords but we condemn the whole structure of rules that sustained feudalism. I am asking people to think similarly about the world economy.

We should condemn as unjust a global economic order that leads to ever-increasing economic disparities - provided this effect is foreseeable and provided it is also avoidable through some alternative institutional design that would foreseeably lead to much less poverty and inequality. Those involved in designing or imposing the existing rules are collectively responsible for the resulting excess deprivations and human rights deficits.