For those not familiar, here is the beginning of the relevant passage[1]:
> 'It is impossible to see reality except by looking through the eyes of the Party. That is the fact that you have got to relearn, Winston. It needs an act of self-destruction, an effort of the will. You must humble yourself before you can become sane.'
> He paused for a few moments, as though to allow what he had been saying to sink in.
> 'Do you remember,' he went on, 'writing in your diary, "Freedom is the freedom to say that two plus two make four"?'
> 'Yes,' said Winston.
> O'Brien held up his left hand, its back towards Winston, with the thumb hidden and the four fingers extended.
> 'How many fingers am I holding up, Winston?'
> 'Four.'
> 'And if the party says that it is not four but five—then how many?'
> ...
[1]: https://2x2.rocks/