Often you have to rely on intuition.

With polio, we've gone several years with no polio in all of Africa, but now with this we're having to go and mop up in that whole region, so it's a bit of a setback for polio. So in parallel we have to go back and get rid of those cases.

I can understand wanting to have millions of dollars; there's a certain freedom, meaningful freedom, that comes with that.

My innovation message, specifically including energy, happened to be the same week that on Monday and Tuesday I announced the Breakthrough Energy Venture Group. Then on that Tuesday afternoon, in December, was when I sat down with him. I explained the US has great science here, this is where the market for these things is going to be. It connects to less pollution, it connects to U.S. jobs, it connects to security, not needing the energy coming from far away.

We have over 60 million machines that can take the same diskette, plug it in and immediately ah, that that software's working. And so it's created the worldwide software industry that... that is so very competitive and moving so quickly.

[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.

I'm an investor in a number of biotech companies, partly because of my incredible enthusiasm for the great innovations they will bring.