According to you, Eugene Fama’s efficient-market theory, stating that financial markets are “informationally efficient,” or that prices of traded assets accurately reflect all known information, has been proved both wrong and right by the credit crunch (“The Grand Illusion,” March 7, 2009). You are only trying to be funny, of course. Fama’s hypothesis is wrong, period. It is one among many mathematical tricks introduced by economists to make their science, well, beautiful. Another is the so-called rational choice theory, stating that all human actions result from weighing all costs and benefits involved. Every such trick has allowed yet another leap in the mathematical conquest of economics. The dismal science has thus long lost all contact with reality for the sake of its own mathematical beauty. As is well known, John Maynard Keynes was a pretty good mathematician, but he eschewed it in his economic theory. He knew that humans are far from rational.