Henry Blodget, founder of Business Insider, says that history suggests we are in the middle of a long bear market cycle that is likely to continue for years to come. He points to historical data suggesting that bull and bear phases last 10-25 years. Based on the fluctuation of P/E ratios from prices at 44 times earnings at the height of bull market that ended in 2000 to prices at 5 times earnings in the bear-market lows, and the an average price of about 15 times earnings, he suggests that bull markets begin when P/E is very low while bear markets have begun while P/E is very high.  Drawing on data from John Hussman of Hussman Funds, Blodget points out that it takes about 20 years for valuations to shift from one extreme to the other. Finally, he points out two facts that suggest we are in a prolonged bear market. First, “stocks are still more expensive than they have been at any time in the past century with the exception of 1929 and 2000.” Second, if we are in the middle of a bull market, the post-2000 bear market phase “would have been one of the shortest in history. And we were starting from the highest valuation in history, by a mile.” Thus, he concludes: “my guess, for what its worth, is that we’re still in the middle of a long bear market.”