This imperviousness of an isolated hypothesis to definitive empirical rejection, and the crucial role of auxiliary hypotheses in serving as a protective barrier, is familiar in the philosophy of science literature as Duhem's Thesis. The mere fact of deflecting disconfirmation onto harmless auxiliary hypotheses is not prima facie an illegitimate ploy; it occurs in all the natural sciences. The issue was not that immunizing stratagems had been resorted to in this instance; rather, it was that the EMH had proven so rabidly tenacious within orthodox economics and in business schools, occupying pride of place for decades within both macroeconomics and finance, that economists had begun to ignore most modern attempts to disprove it. The lesson for crisis watchers that we shall entertain is that the EMH cannot be killed easily, and maybe not at all within the neoclassical parameters of the current economics profession.

Philip Mirowski, Never Let a Serious Crisis …, loc. 753