Economists operate with this image of the homo economicus, the rational economic agent, and while such agents are rare in the wider world, they are common in economics departments. Exemplifying the homo economicus paradigm, economists typically choose their research projects and hypotheses so as to promote their own careers, to maximize their lifetime income. This explains the astonishing pressures toward conformity in academic economics: how deviant views (except those by a few who have already achieved stardom) get crushed by an army of conformists.

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.

Economists operate with this image of the homo economicus, the rational economic agent, and while such agents are rare in the wider world, they are common in economics departments. Exemplifying the homo economicus paradigm, economists typically choose their research projects and hypotheses so as to promote their own careers, to maximize their lifetime income. This explains the astonishing pressures toward conformity in academic economics: how deviant views (except those by a few who have already achieved stardom) get crushed by an army of conformists.

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.

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.

Think of US slavery in 1850, or the subjection of women. Both of these injustices could have been - and were! - defended by pointing out, quite correctly, that this situation of slaves and women had been improving throughout the preceding century. Slaves, in particular, were worked less hard, beaten and raped less frequently, better fed, and less often ripped apart from their families. So would a celebration of moral progress have been appropriate in 1850? Surely not. Slavery could have been and should have been abolished - then, if not before.

By using general consumption PPPs, the World Bank is, in effect, saying to the poor: "Sure, you cannot buy as much food as the dollar value we attribute to your income would buy in the United States. But then you can buy much more by way of services than you could buy with this PPP equivalent in the United States." But what consolation is this? The poor do not buy services - they are services, on their luckier days.