People who feel the world is tilted against them will spawn the kind of hatred that is very dangerous for all of us. I think it's a healthy sign that there are demonstrators in the streets. They are raising the question of 'is the rich world giving back enough?'

Taking a look back, one big reqret is, I left Harvard with no real awareness of the awful inequities in the world. The appalling disparities of health and wealth and opportunity that condemned millions of people to the lives of despair. I learned a lot here at Harvard about new ideas and economics, and politics. I got great exposure to the advances being made in the sciences. But humanities greatest advances are not in its discoveries, but in how those discoveries are applied to reduce inequity.

There was a concept a long time ago that you would do a different type of reactor called a "fast reactor," that would make a bunch of another element called plutonium, and then you would pull that out, and then you would burn that. That's called "breeding" in a fast reactor. That is bad because plutonium is nuclear weapons material. It's messy. The processing you have to get through is not only environmentally difficultly, it's extremely expensive.

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.

We win because we hire the smartest people. We improve our products based on feedback, until they're the best. We have retreats each year where we think about where the world is heading.

Part of the magic of economic growth is how you educate people, and the leading economies have to stay in front of that. From an economic point of view, it affects competitiveness and creates jobs. Or from a social justice point of view, you can take someone in the bottom tier of income and let him compete to be a doctor or lawyer. The education system is the only reason the dream of equal opportunity has a chance of being delivered - and we're not running a good education system.

Ninety percent of the cases of polio are in security-vulnerable areas.