My mom was on the United Way group that decides how to allocate the money and looks at all the different charities and makes the very hard decisions about where that pool of funds is going to go.

You have to have a certain realism that government is a pretty blunt instrument and without the constant attention of highly qualified people with the right metrics, it will fall into not doing things very well.

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.

Make it just like a Mac.

My guideline has always been to avoid a focus on me personally. Not because of any deep, dark secrets. Rather just a sense of privacy.

With nuclear weapons, you'd think you would probably stop after killing 100million. Smallpox won't stop. Because the population is naïve, and there are no real preparations. That, if it got out and spread, would be a larger number.

That way you can be certain to learn something you didn't know previously.