What does Winston know about Big Brother that many other people don't know in "1984"?
What is it that happens to Comrade Withers? I was told it had to do with Big Brother but I'm not seeing it.
In addition, Winston struggles with the idea that Big Brother is actually changing history or whether or not he believes these are "true mistakes". Consciously, he knows that these are actually changes Big Brother chooses to make in the history of the world, but subconsciously he is questioning what he has been taught his whole life. This is part of the major struggle that Winston has with society as well as himself.
Big Brother, who is the embodiment of the Party, literally recreates the past to suit his objectives. Winston is one of the select few who know this about Big Brother; he is intimately involved in this deception personally because his job at the Ministry of Truth requires him to fabricate documentary evidence to support whatever Big Brother chooses to be the truth at the moment. Comrade Withers, beloved by the masses, had been a prominent member of the inner Party and had received a prestigious award, the Order of Conspicuous Merit. Then, for reasons unknown, he had fallen out of favor with Big Brother and was vaporized. At his job, Winston receives the assignment of obliterating all record of Withers' existence. In order to do this, Winston creates an entirely fictional entity, Comrade Oglivy, who embodies all the qualities for which Withers once was reknowned and more, and upon whom the citizens can focus their attention. At the same time, he methodically erases all references to Withers that exist in the media. Once Winston is done, Withers is effectively "an unperson...he did not exist; he had never existed". Winston has firsthand knowledge of the complete depth of mind-control which Big Brother exercises over the unsuspecting masses. By recreating history to suit his objectives, Big Brother dictates unequivocalby what is perceived as reality and truth (Part I, Chapter 4).