The only role other than paying their taxes, whatever those are, the only role for philanthropy broadly - of which the rich should give disproportionately - the more, the better - and I think there is a positive trend in that direction - there are certain risk-taking things, like trying out a new type of charter school or funding a new kind of medicine.

...one of the most inventive forms of creative capitalism involves someone we all know very well. A few years ago, I was sitting in a bar here in Davos with Bono. Late at night, after a few drinks, he was on fire, talking about how we could get a percentage of each purchase from civic-minded companies to help change the world. He kept calling people, waking them up, and handing me the phone to show me the interest.

If you think of global public goods like polio eradication, the kind of risk-taking new approach, philanthropy really does have a role to play there, because government doesn't do R&D about new things naturally as much as it probably should, and so philanthropy's there.

I don't think I would have spent time learning about the immune system if understanding vaccines weren't something I considered very important.

Harnessing steam power required many innovations, as William Rosen chronicles in the book 'The Most Powerful Idea in the World.'

I hope corporations will dedicate a percentage of their top innovators' time to issues that could help people left out of the global economy. This kind of contribution is even more powerful than giving cash or offering employees' time off to volunteer. It is a focused use of what your company does best. It is a great form of creative capitalism, because it takes the brainpower and makes life better for the richest, and dedicates some of it to improving the lives of everyone else.

'I don't know' has become 'I don't know yet'.