Disasters redistribute money from taxpayers to construction workers, from insurance companies to homeowners, and even from those who once lived in the destroyed city to those who replace them. It's remarkable that this redistribution can happen so smoothly and quickly, with devastated regions reinventing themselves in a matter of months.

When Americans are asked to rank professions in terms of honesty and ethics, insurance agents routinely end up near the bottom of the list - somewhere between politicians and car salesmen. Generally, insurers are seen as clever hucksters who prey on insecurity and ignorance to sell people what they don't need at prices they shouldn't have to pay.

The smartest groups, then, are made up of people with diverse perspectives who are able to stay independent of each other. Independence doesn't imply rationality or impartiality, though. You can be biased and irrational, but as long as you're independent, you won't make the group any dumber.

This intelligence, or what I'll call "the wisdom of crowds," is at work in the world in many different guises. It's the reason the Internet search engine Google can scan a billion Web pages and find the one page that has the exact piece of information you were looking for. It's the reason it's so hard to make money betting on NFL games, and it helps explain why, for the past fifteen years, a few hundred amateur traders in the middle of Iowa have done a better job of predicting election results than Gallup polls have.

In conditions of uncertainty, humans, like other animals, herd together for protection.

Wall Street has come a long way from the insider-dominated world that was blown apart by the Great Depression.

Companies often become victims of their own mythologies.