Despite great progress around the world in getting more kids into schools, too many leave without even the most basic skills. In India's rural Andhra Pradesh, for instance, only about one in twenty children in fifth grade can perform basic arithmetic. The problem is that schooling is not the same as learning. In The Rebirth of Education, Lant Pritchett uses two metaphors from nature to explain why. The first draws on Ori Brafman and...