You'll sometimes hear from people that they actually do a better job of getting their work done when they have a lot of other obligations - in effect, it removes the possibility of procrastinating.

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

Publishers, naturally, loathe used books and have developed strategies to depress the secondhand market. They bring out new, even more expensive editions of popular textbooks every three to four years, in a classic cycle of planned obsolescence.

Technological innovation has dramatically lowered the cost of computing, making it possible for large numbers of consumers to own powerful new technologies at reasonably low prices.

Popular as Keynesian fiscal policy may be, many economists are skeptical that it works. They argue that fine-tuning the economy is a virtually impossible task, and that fiscal-stimulus programs are usually too small, and arrive too late, to make a difference.

The smartest groups, then, are made up of people with diverse perspectives who are able to stay independent of each other.

If private-equity firms are as good at remaking companies as they claim, they don't need tax loopholes to make money.