In Book 3, Chapter 1 of 1984, Winston is in a cell. He believes he's somewhere in the Ministry of Love. A hungry ache in his belly is something he can't shake away, and he imagines what will happen to him. The smash of truncheons or billy clubs on his body, begging for mercy from the floor, it all runs through his head.
And he thinks of Julia. He doesn't know where she is. Winston's one hope is that O'Brien will save him somehow.
Others The years arrive. Ampleforth, Winston's coworker and a poet. Surprise, surprise, his neighbors, the Parsons.
There's a mean-looking man with a face as thin as a skull. And when the starving, skull-faced man is told to go to Room 101, he begs for anything but that. Eventually, the doors open.
It's O'Brien. They've got you, too, Winston cries. But he finds out that O'Brien is actually with Big Brother. They got me a long time ago, O'Brien says.
O'Brien comes in with a guard who now slams a truncheon onto Winston's elbow. Now the thought police always come for people at night, but Winston hoped to find the place where there is no darkness. He thought he would be safe there.
As it turns out, he's there now, but it's a cell where the lights are always on. Orwell was foreshadowing this cell with the lights on rather than giving readers a sign of hope. O'Brien reveals that he's been a faithful party member for a long time.
Winston had always known it. As readers, we've seen Winston wonder about a lot of things, but he's made a lot of really important, interesting choices, and we've seen him grow, especially in a moral way. Now, as readers, we've trusted Winston when he believed Julia loved him. We may have trusted Winston's original instinct about O'Brien. The story is told through Winston, and readers have to trust that he's a reliable narrator.
1984 makes the readers doubt their own assumptions, just as Winston has to do. There are many reasons why the readers doubt the story. There are two possible answers here. One, that Winston was hiding the knowledge about O'Brien from himself.
Psychologists would call this self-deception. And perhaps in a world of doublethink, Winston should not have been fooled by this. On the other hand, maybe O'Brien is playing with Winston's mind, revising history. Even in this statement, it convinces Winston that he has always known what he says he knows now.