I guess everyone is a Keynesian in a foxhole. - Robert Lucas

In the present decade, the U.S. economy has undergone its first major depression since the 1930’s, to the accompaniment of inflation rates in excess of 10 percent per annum. These events have been transmitted [...] to other advanced countries and in many cases have been amplified. These events did not arise from a reactionary reversion to outmoded, 'classical' principles of tight money and balanced budgets. On the contrary, they were accompanied by massive government budget deficits and high rates of monetary expansion, policies which, although bearing an admitted risk of inflation, promised according to modern Keynesian doctrine rapid real growth and low rates of unemployment. That these predictions were wildly incorrect and that the doctrine on which they were fundamentally flawed are now simple matters of fact, involving no novelties of economic theory. The task now [...] is to sort through the wreckage, determining which features of that remarkable intellectual event called the Keynesian Revolution can be salvaged and put to use and which others must be discarded.”

The Keynesian Revolution was, in the form in which it succeeded in the United States, a revolution in method. This was not Keynes’s intent, nor is it the view of all of his most eminent followers. Yet if one does not view the revolution in this way, it is impossible to account for some of its most important features.

For policy, the central fact is that Keynesian policy recommendations have no sounder basis, in a scientific sense, than recommendations of non-Keynesian economists or, for that matter, non-economists.