I think any statement about stock prices is always suspect unless it's made by Warren Buffett.

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.

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.

[Smart] is an elusive concept. There's a certain sharpness, an ability to absorb new facts. To ask an insightful question. To relate to domains that may not seem connected at first. A certain creativity that allows people to be effective.

On the supply side, for innovation, you'd say, go look at those R&D budgets, and they haven't moved in the last 20 years. In the case of the US - which is the majority of R&D funding across every category you can name: health, energy, whatever - it's been about $5 billion a year from the Department of Energy.

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

The nuclear approach I'm involved in is called a traveling-wave reactor, which uses waste uranium for fuel. There's a lot of things that have to go right for that dream to come true - many decades of building demo plants, proving the economics are right. But if it does, you could have cheaper energy with no CO2 emissions.