Megan McArdle tackles the central thesis of Thomas Piketty’s new book, “Capital in the Twenty-First Century.” Piketty says that the biggest problem facing the world economy is income inequality. To solve that problem, Piketty suggests a huge tax on the wealthiest group of Americans, which would be then redistributed to the poor. Would this solve problems? Megan thinks no. What do you think? (I’m still mulling over my response. And feeling like I should read the book first.)