In January 2008, during the World Economic Forum’s annual meeting in Davos, I was summoned to a conference room to meet Ray Dalio, founder of the mighty Bridgewater hedge fund. His team handed me a vast report, the size of a bible. This, I was solemnly told, represented Dalio’s views on the credit cycle. I duly skimmed it — and then dumped it into a bin, since it was so heavy. That turned out to be a big mistake.

When the great financial crisis exploded later that year, Dalio was hailed as one of its prophets, in large part because of the forecasts in that report I discarded. “I calculated the rate at which debt growth [is] going to occur and the supply and demand for credit, relative to economic fundamentals,” he recently told me by way of explanation.