More than four years after the financial crisis began, the world's major advanced economies remain deeply depressed, in a scene all too reminiscent o… - Paul Krugman

It is important to realize that even now Fed officials are not quite sure how they pulled this rescue off. At the height of the crisis it seemed entirely possible that cutting interest rates would be entirely ineffectual—after all, if nobody can borrow, what difference does it make what the price would be if they could? And if everyone had believed that the world was coming to an end, their panic might—as in so many other countries—have ended up being a self-fulfilling prophecy. In retrospect Greenspan seemed to have been like a general who rides out in front of his demoralized army waves his sword and shouts encouragement, and somehow turns the tide of battle: well done, but not something you would want to count on working next time.

So what's the moral? We've seen how the insistence on models that meet the standards of rigor in mainstream economics can lead to neglect of clearly valuable ideas. Does this mean that the whole emphasis on models is wrong? Should we make a major effort to open up economics, to relax our standards about what constitutes an acceptable argument? No—the moral of my tale is nowhere near that easy. Economists can often be remarkably obtuse, failing to see things that are right in front of them. But sometimes a bit of obtuseness is not entirely a bad thing.

If Keynes was Luther, Friedman was Ignatius of Loyola, founder of the Jesuits. And like the Jesuits, Friedman’s followers have acted as a sort of disciplined army of the faithful, spearheading a broad, but incomplete, rollback of Keynesian heresy. By the century’s end, classical economics had regained much though by no means all of its former dominion, and Friedman deserves much of the credit.