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.

Social rules are susceptible to moral analysis. This is, again, relatively familiar in the domestic case, where we now condemn slavery as unjust. And when we affirm this judgment, we're not merely saying that all those people who owned slaves were unethical people; they shouldn't have done that. We do believe this, but that's only part of the point. We also believe that the fugitive slave laws were unjust.

Whatever we, as prospective participants unaware of our specific features, would desire society to be like is what, morally speaking, we ought to institute.

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.

Often vastly more important, international agreements are not routinely published in draft form or publicly debated, and civil society organizations and ordinary citizens often learn of important global institutional design decisions only after they have already been finalized and adopted. The only reliable way to be kept informed and to exert timely influence is by lobbying and paying the politicians and their negotiators.

Purchasing power parities are not a reasonable method for comparing households across countries or currencies. The reason for this is simply that PPPs are sensitive to the prices of all the commodities, goods and services, that households are consuming worldwide, with each commodity weighted in the calculations according to its share in international household consumption expenditure.

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