A mixture of gullibility and cynicism had been an outstanding characteristic of mob mentality before it became an everyday phenomenon of masses. In an ever-changing, incomprehensible, world the masses had reached the point where they would, at the same time, believe everything and nothing, think that everything is possible and that nothing was true. The mixture in itself was remarkable enough, because it spelled the end of the illusion that gullibility was a weakness of unsuspecting primitive souls and cynicism the vice of superior and refined minds. Mass propaganda discovered that its audience was ready at all times to believe the worst, no matter how absurd, and did not particularly object to being deceived because it held every statement to be a lie anyhow. The totalitarian mass leaders based their propaganda on the correct psychological assumption that, under such conditions, one could make people believe the most fantastic statements one day, and trust if the next day they were given irrefutable proof of their falsehood, they would take refuge in cynicism; instead of deserting the leaders who had lied to them, they would protest that they had known all along the statement was a lie and would admire the leaders for their superior tactical cleverness.

Hannah Arendt (1906-1975) German-American philosopher, political theorist
The Origins of Totalitarianism, Part 3, ch. 2 (1951)
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