The hedge fund known as "Long Term Capital Management" collapsed last fall through overconfidence in its highly leveraged methods, despite I.Q.'s of its principals that must have averaged 160. Smart people aren't exempt from professional disasters from overconfidence. Often, they just run aground in the more difficult voyages they choose, relying on their self-appraisals that they have superior talents and methods.

If you can buy the best companies, over time the pricing takes care of itself.

You must know the big ideas in the big disciplines, and use them routinely - all of them, not just a few. Most people are trained in one model - economics, for example - and try to solve all problems in one way. You know the old saying: to the man with a hammer, the world looks like a nail. This is a dumb way of handling problems.

We like our current shareholders and don't want to entice anyone to become one. It would help current shareholders to hear our CEOs [of the Berkshireoperating subsidiaries], but we promised them they could spend 100% of their time on their business. We place no impediments on them running their businesses. Many have expressed to me how happy they are that they don't have to spend 25% of time on activities they didn't like.

The interesting thing is the field is so big - it's enormous. One thing a modern civilization needs is energy.

How could economics not be behavioral? If it isn't behavioral, what the hell is it?

When it gets into these spikes, with shortages and uproar and so forth, people go bananas, but that's capitalism.