While being tortured by O'Brian, Winston will do or say anything to rid the pain he was being caused. The part that was significant to me was that after a torture session, Winston's ENTIRE way of thinking was shifted. Well 2+2=4, Winston was unsure if it did, for all he knew anymore, it was 3, or even 5. This scene was sad, as it seemed that Winston lost all of himself, and submitted to everything he was being told. Very significant.