Robert Schiller agues that the current stock market environment is just like the 1920’s before the stock market crash. “The 1920s is quite a legend that people are often thinking about,” Shiller said Friday on CNBC’s “Trading Nation.” “I look at 1929 particularly as the end of the roaring ’20s and it ended in a bout of speculation. Between May and September of ’29 the stock market went up over 30 percent in just a few months.”