George Orwell. One thousand nine hundred eighty four (№ 387908)

To know and not to know, to have the complete truth and speak carefully fabricated lie, to simultaneously adhere to two contradictory opinions, knowing that they contradict one another, and believe both to turn logic against logic, not to recognize morals and at the same time swear by this morality, to believe that democracy is impossible, and to assert that the Party upholds democracy, to forget everything ordered to forget, and then, if necessary, to re-remember it and, most importantly, to apply this dialectic to the dialectic itself. This was the highest achievement: deliberately impose unconsciousness and then to forget that you were hypnotized. Even to understand the word "doublethink", it was necessary to apply doublethink.