Talk about locking the stable door after the horse has bolted; now Ben Bernanke, chairman of the Fed, has said that in future the Fed must take proactive steps to try and stop the emergence of bubbles. Ben said that bubbles were a "dangerous phenomenon", yesterday, when talking at the Economic Club in New York. Okay, it's pretty obvious, really. But actually, in a way, this should draw us to the heart of the matter of this crisis, because it was Alan Greenspan who deliberately followed a policy of not trying to deflate bubbles. Look even deeper, though, and another point of view emerges altogether.