The US in some ways has been the best. Who figured out shale gas? Although that wasn't a good thing [for CO2 levels], it was very innovative. It's led to low-cost energy. Who figured out nuclear power? Largely the United States. Once you get past the steam engine, which is mostly British, then the US has been at the center of most of the energy things that have happened.

Teaching is the human thing, in terms of building the kids' self-confidence, so if we take the broad ways that we want to see society to be better, science can only provide certain pieces of that.

Technology is just a tool. In terms of getting the kids working together and motivating them, the teacher is the most important.

[AIDS ] is not a short-term emergency but it is something that, just like smallpox was many decades ago, we should aim for complete eradication.

Energy innovation is not a nationalistic game.

I really do think cancer will largely be a solved problem. I think most of the infectious diseases like malaria - our foundation is very involved - once we're finishing polio eradication, then starting up this malaria eradication, and getting that done as fast as we can.

The poor can't wait. Philanthropists needed to carry on being generous.