1984

"Winston sank his arms to his sides and slowly refilled his lungs with air.
His mind slid away into the labyrinthine world of doublethink. To know
and not to know, to be conscious of complete truthfulness while telling
carefully constructed lies, to hold simultaneously two opinions which
cancelled out, knowing them to be contradictory and believing in both of
them, to use logic against logic, to repudiate morality while laying claim
to it, to believe that democracy was impossible and that the Party was the
guardian of democracy, to forget whatever it was necessary to forget, then
to draw it back into memory again at the moment when it was needed, and
then promptly to forget it again: and above all, to apply the same process
to the process itself. That was the ultimate subtlety: consciously to
induce unconsciousness, and then, once again, to become unconscious of
the act of hypnosis you had just performed. Even to understand the word
'doublethink' involved the use of doublethink."

George Orwell 1984