Contrary to Piketty’s rentier hypothesis, I don’t see anyone on the [Forbes 400 list of the wealthiest Americans] whose ancestors bought a great parcel of land in 1780 and have been accumulating family wealth by collecting rents ever since. In America, that old money is long gone - through instability, inflation, taxes, philanthropy, and spending.

India is more of an aid recipient than a provider of aid.

It's the poorer people in tropical zones who will get really hit by climate change - as well as some ecosystems, which nobody wants to see disappear.

AIDS we're - most of these diseases - we are down from the peak. We're down about 40 per cent from the peak and if we got the right vaccines, which are at the early stage of discovering, then the numbers would come down very dramatically. So that's why we talk about it as an emergency.

More and more software would just increase the number of tasks that the computer would help solve.

The world is progressing and resources are becoming more abundant. I'd rather go into a grocery store today than a king's banquet a hundred years ago.

The Gates Foundation has learned that two questions can predict how much kids learn: 'Does your teacher use class time well?' and, 'When you're confused, does your teacher help you get straightened out?'