This chapter turns to the collapse of moral judgment Arendt saw in the early weeks of the Third Reich, and which she connects to the collapse of common sense and adherence to conspiracy theories in mass societies. The chapter draws on The Origins of Totalitarianism, coupled with contemporary “virtue epistemology” – the study of intellectual virtues and vices and their relation to knowledge. Arendt, I argue, is an exceptionally insightful virtue epistemologist. The chapter analyzes Arendt’s account of how European social conditions in the nineteenth and twentieth centuries led to the collapse of common sense in the face of a barrage of political lies. She warns that “if everyone always lies to you, the consequence is not that you believe the lies, but that no one believes anything at all anymore.” The result is a dangerous mix of gullibility and cynicism, what in the chapter I label culpable credulousness.