Stephan:   The myth of America is that no matter where you start you can end up on top. And it is true that for exceptional people, with a few good breaks it is true -- Oprah, President Obama, Associate Justice Sotomayor. But the truth is only a tiny fraction of people are exceptional in that way. For most, today, as the data makes clear, where you start is probably going to be where you end. This is why we need to support programs that make upward mobility possible. Society is healthier when class distinctions do not become ironbound, as has happened in the U.S.