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.

It is hard to sell Congress and the American people on foreign aid. Is it harder to do that than it is to sell billionaires on the idea that they should give all their money away.

I remember thinking quite logically that I didn't want to spoil my children with wealth and so that I would create a foundation, but not knowing exactly what it would focus on.

I would certainly use my voice to try and avoid anything that undermines confidence, so that parents are using vaccines fully.

We all know that there are these exemplars who can take the toughest students, and they'll teach them two-and-a-half years of math in a single year.

Whether you believe it a moral imperative or in the rich world's enlightened self-interest, securing the conditions that will lead to a healthy, prosperous future for everyone is a goal I believe we all share.

When you develop software, the people who write the software, the developers are the key group but the testers also play an absolutely critical role. They're the ones who ah, write thousands and thousands of examples and make sure that it's going to work on all the different computers and printers and the different amounts of memory or networks that the software'11 be used in. That's a very hard job.