It was as though some huge force were pressing down upon you--something that penetrated inside your
skull, battering against your brain, frightening you out of your beliefs, persuading you, almost,
to deny the evidence of your senses. In the end the Party would announce that two and two made
five, and you would have to believe it. It was inevitable that they should make that claim sooner
or later: the logic of their position demanded it. Not merely the validity of experience, but the
very existence of external reality, was tacitly denied by their philosophy. The heresy of heresies
was common sense. And what was terrifying was not that they would kill you for thinking otherwise,
but that they might be right. For, after all, how do we know that two and two make four? Or that
the force of gravity works? Or that the past is unchangeable? If both the past and the external
world exist only in the mind, and if the mind itself is controllable... what then?