Do You Know What You Don't Know?

"There are two kinds of investors, be they large or small:  Those who don't know where the market is headed, and those who don't know that they don't know.  Then again, there is third type of investor -- the investment professional, who indeed knows that he or she doesn't know, but whose livelihood depends on appearing to know."

- William Bernstein, author of The Intelligent Asset Allocator