Many years ago, when I was a college student, I took a course from John Kenneth Galbraith. On the first day of class, Professor Galbraith gave a brilliant opening lecture, after which the students gave him a standing ovation. Galbraith kept on giving brilliant opening lectures the whole semester. But, instead of standing ovations, there were now dwindling numbers of students and some of them got up and walked out in the middle of his lectures. Galbraith never got beyond the glittering generalities that marked his first lecture. After a while, the students got tired of not getting any real...