I think given all the different imperatives - getting energy to Africa, security of energy, climate change, that we should be spending half as much as we spend on health, which will get you all the way up to $15 billion - the health people don't like it when things get compared to their number.

K to 12 is partly about babysitting the kids so the parents can do other things.

There is this thing called the GPL (Gnu Public Licence), which we disagree with... nobody can ever improve the software.

There's 20 companies that I have investments in - some batteries, some solar-thermal, one big nuclear thing. We need hundreds and hundreds of companies like that, so that in a 20-year time frame we really are starting to change the energy infrastructure.

(On being the world's richest man) I wish I wasn't ... There's nothing good that comes out of that. You get more visibility as a result of it.

But the improvements will happen faster and last longer if we can channel market forces, including innovation that's tailored to the needs of the poorest, to complement what governments and nonprofits do. We need a system that draws in innovators and businesses in a far better way than we do today.

If you are low income in the United States, you have a higher chance of going to jail than getting a 4-year degree.