If people want capital gains taxed more like the highest rate on income, that's a good discussion. Maybe that's the way to help close the deficit.

Flying cars are not a very efficient way to move things from one point to another.

The pace of progress in biology creates a foundation that naturally gets picked up by the biotech and pharmaceutical industry to solve rich-world diseases. This is attractive science. It's science that people want to work on.

Until recently, over 98 percent of teachers just got one word of feedback: Satisfactory. If all my bridge coach ever told me was that I was 'satisfactory,' I would have no hope of ever getting better.

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.

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.

[Melinda Gates] is a lot of fun to work with. There's some of the people skills that she's better at and cares about more. It'd be a mistake not to think of her as very numerical and interested in the science. I enjoy, if I get ahead of her, say, understanding the immune system, then we can spend a few hours, where I'm going through how amazing it is and interesting, and how that affects our creating new products, so I've always had a partner.