My experience of malaria was just taking anti-malarials, which give you strange dreams, because I don't want to get malaria.

I understand how every healthy child, every new road, puts a country on a better path, but instability and war will arise from time to time, and I'm not an expert on how you get out of those things.

We always overestimate the change that will occur in the next two years and underestimate the change that will occur in the next ten. Don't let yourself be lulled into inaction.

Vision without execution is daydreaming.

Now, we put out a lot of carbon dioxide every year, over 26 billion tons. For each American, it's about 20 tons. For people in poor countries, it's less than one ton. It's an average of about five tons for everyone on the planet. And, somehow, we have to make changes that will bring that down to zero.

In a system of capitalism, as people's wealth rises, the financial incentive to serve them rises. As their wealth falls, the financial incentive to serve them falls, until it becomes zero. We have to find a way to make the aspects of capitalism that serve wealthier people serve poorer people as well.

When making choices, or setting policies about the economy, education or medicine, society is best served by electing people who are particularly hardworking, intelligent and interested in long-term thinking.