The collective income of all these people - the bottom half - is less than three percent of global household income, and so there is a grotesque maldistribution of income and wealth.

A few hundred years ago, perhaps 85 or even 90 percent of humanity lived below a standard of living that today only 40 or 45 percent fail to reach. But at that earlier time only part of this poverty could have been eradicated, and this at substantial cost not only to the pleasures of the affluent, but also to their well-being and to human culture. In our time, nearly all severe poverty could be eradicated at a cost to the affluent that is truly trivial.

Domestic power structures are shaped in good part by global arrangements.

Over the period from 1988 to 2005, the income share of the top five percent has grown by about 3.5 percent of global household income, and the shares of all the other groups have diminished. The greatest relative reduction was in the bottom quarter, which lost about one third of its share of global household income, declining from 1.155 to 0.775 percent, and now is even more marginalized.

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.

The bottom quarter of the human population has only three-quarters of one percent of global household income, about one thirty-second of the average income in the world, whereas the people in the top five percent have nine times the average income. So the ratio between the averages in the top five percent and the bottom quarter is somewhere around 300 to one - a huge inequality that also gives you a sense of how easily poverty could be avoided.

Though people could, in principle, cross national borders to reach places where their work is more highly rewarded, they are in fact prevented from doing so. As a result, huge differences also persist in the price of labor, as you can see when you get a haircut in rural India or hire a driver or babysitter in Bolivia. You can easily buy such services at one-fiftieth the price you would pay in London, Hamburg or Manhattan.