Orwell, George — Nineteen eighty-four [985]

Once again the sense of helplessness assailed him. He knew, or he could imagine, the arguments which proved his own non-existence; but they were nonsense, they were only a play on words. Did not the statement, ‘You do not exist’, contain a logical absurdity? But what use was it to say so? His mind shrivelled as he thought of the unanswerable, mad arguments with which O’Brien would demolish him. — Orwell, George, Nineteen eighty-four, 985

Note

Winston rehearsing the refutation of his own non-existence and feeling it useless — knowing the doublethink is logically absurd yet powerless against it — captures the condition where rational self-defense has already been emptied out by sustained assault.