The power of capitalism to mediate the gap between rich and poor is pretty incredible. Indeed, I think, year by year, the gap gets less.

In American math classes, we teach a lot of concepts poorly over many years. In the Asian systems they teach you very few concepts very well over a few years.

Security is, I would say, our top priority because for all the exciting things you will be able to do with computers - organizing your lives, staying in touch with people, being creative - if we don't solve these security problems, then people will hold back.

As I see it, there are two great forces of human nature: self-interest, and caring for others. Capitalism harnesses self-interest in a helpful and sustainable way, but only on behalf of those who can pay. Government aid and philanthropy channel our caring for those who can't pay. But to provide rapid improvement for the poor we need a system that draws in innovators and businesses in a far better way than we do today.

Depending on how quickly you get ocean rise, you have people who live in river deltas [at risk]. Bangladesh is largely a river delta, and the rising sea level means that when storms come in, the human sanitation is backing up, the ability to farm, it's destructive-type situations like you saw in New Orleans with Katrina. You're increasing the frequency of that stuff in low-lying areas fairly dramatically.

Business isn't that complicated. I wouldn't want to put it on my business card.

Is the rich world aware of how four billion of the six billion live? If we were aware, we would want to help out, we'd want to get involved.