As I see it, the economics profession went astray because economists, as a group, mistook beauty, clad in impressive-looking mathematics, for truth. Until the Great Depression, most economists clung to a vision of capitalism as a perfect or nearly perfect system.
Friedman made a compelling case against any deliberate effort by government to push unemployment below its “natural” level (currently thought to be about 4.8 percent in the United States): excessively expansionary policies, he predicted, would lead to a combination of inflation and high unemployment - a prediction that was borne out by the stagflation of the 1970s, which greatly advanced the credibility of the anti-Keynesian movement.
Even so, you might have thought that the differing worldviews of freshwater and saltwater economists would have put them constantly at loggerheads over economic policy. Somewhat surprisingly, however, between around 1985 and 2007 the disputes between freshwater and saltwater economists were mainly about theory, not action.
市場が不完全だと論じる「塩水」学派もいたが、経済政策については彼らの意見も同じだった。財政政策は有害無益で、金融政策がマクロ経済政策と同義になり、経済はFRBによって完全にコントロールできると信じられるようになった。80年代から2000年代にかけて、大平穏(Great Moderation)とよばれる経済の安定した状況が続き、経済学も平穏になった。
But the crisis ended the phony peace. Suddenly the narrow, technocratic policies both sides were willing to accept were no longer sufficient - and the need for a broader policy response brought the old conflicts out into the open, fiercer than ever.
Larry Summers once began a paper on finance by declaring: “THERE ARE IDIOTS. Look around.” But what kind of idiots are we talking about? Behavioral finance, drawing on the broader movement known as behavioral economics, tries to answer that question.