“In a way, the world-view of the party imposed itself most successfully on the people incapable of understanding it. They could be made to accept the most flagrant violations of reality, because they never fully grasped the enormity of what was demanded of them, and were not sufficiently interested in public events to notice what was happening. By lack of understanding, they remained sane. They simply swallowed everything, and what they swallowed did them no harm, because it left no residue behind, just like a grain of corn will pass undigested through the body of a bird."
~George Orwell, 1984

"In our society, those who have the best knowledge of what is happening are also those who are furthest from seeing the world as it is. In general, the greater the understanding, the greater the delusion; the more intelligent, the less sane.

One clear illustration of this is the fact that war hysteria increases in intensity as one rises in the social scale. Those whose attitude towards the war is most nearly rational are the subject peoples of the disputed territories. To these people the war is simply a continuous calamity which sweeps to and fro over their bodies like a tidal wave. Which side is winning is a matter of complete indifference to them. They are aware that a change of overlordship means simply that they will be doing the same work as before for new masters who treat them in the same manner as the old ones. The slightly more favoured workers whom we call 'the proles' are only intermittently conscious of the war. When it is necessary they can be prodded into frenzies of fear and hatred, but when left to themselves they are capable of forgetting for long periods that the war is happening. It is in the ranks of the Party, and above all of the Inner Party, that the true war enthusiasm is found. World-conquest is believed in most firmly by those who know it to be impossible. This peculiar linking-together of opposites -- knowledge with ignorance, cynicism with fanaticism -- is one of the chief distinguishing marks of society.

If human equality is to be for ever averted -- if the High, as we have called them, are to keep their places permanently -- then the prevailing mental condition must be controlled insanity."
~George Orwell