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.

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.

It is for the poor people's sake, above all, that we urgently need more unity and better organization and need to concentrate our reform efforts in order to really to achieve reforms, one by one.

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.

Companies are actually much better than governments and other bureaucracies at organizing in a holistically efficient way the extremely complex path from the examination of molecules all the way to the delivery of medicines to patients. Already in the conception and selection of research projects, companies would anticipate all the challenges down the line that they will need to overcome in order to achieve actual health impact. Bureaucratic organizations, by contrast, are notoriously bad at this sort of optimizing.

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.

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