Miracles, by definition, are rare. And pronouncements of them often belie a lack of curiosity as to how the world works. If a phenomenon cannot be readily understood, often miracle status is assigned to it. David Viniar, the chief financial officer at Goldman Sachs, pronounced that 25-standard deviation events had occurred on several successive days during the turmoil. Alan Greenspan too has referred to the proceedings of recent years as once-in-a-century events. Perhaps they are right to