We should not think of poverty eradication as a matter of collecting money and giving it to the poor so much as of reforming the global rules that are disadvantaging the poor and making it impossible for them to fend for themselves.

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.

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.

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.

It is irrational to charge high prices for socially valuable innovations as this guarantees that they will be underutilized. It is much better to sell them at cost and then to reward the innovator in some other way. This is not always possible, because in some cases the value of an innovation is in the eye of the beholder; it's very difficult to value how much a new Madonna song is worth, for example. But in the case of medicines, green technologies and seeds in agriculture, such an alternative reward mechanism is fairly straightforward.

The global financial crisis is a great opportunity to showcase and propagate both causal and moral institutional analysis. The crisis shows major flaws in the way the US financial system is regulated and, more importantly, in our political system, which is essentially a bazaar of legalized bribery where financial institutions can buy themselves the governmental regulations they want, along with the regulators who routinely receive lucrative jobs in the industry whose oversight had formerly been their responsibility, the so-called revolving-door practice.

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.