book 1 Ch. 7-8, book 2 Ch. 1-2

Pg. 44 "‘Who controls the past,’ ran the Party slogan, ‘controls the future: who controls the present controls the past.’ And yet the past, though of its nature alterable, never had been altered. Whatever was true now was true from everlasting to everlasting. It was quite simple. All that was needed was an unending series of victories over your own memory. ‘Reality control’, they called it: in Newspeak, ‘doublethink'." 

The Party is talking about themselves in this quote. They make sure that they control the past, so that they can control the future and the present. This is the Party's way of making sure that they are always right and can never be called out for being wrong. The Party also makes sure that they use quotes that directly relate to them. They have to do this because everything has to be about the Party or no one will follow their rules. 'Reality control' is what is happening now in our country with fake news. If newspapers are paid to print fake news by different companies, then the readers will believe it and not go out and see if the information is real or not. In our country, we can at least search up and do our own research. In Oceania, they cannot do their own research and only know what the Party tells them. They can use their own minds to remember things that happened, but history will be rewritten anyways so there is no point. With lies being told over and over again, ignorance is definitely peace. Some people in Oceania might rather want lies that make them feel good rather than the truth that doesn't make them feel good or makes them question the Party's credibility. Another thing is that Orwell writes that the past has never been changed because what is true right now will always be true. This shows how the Party values the present. They want everything to be according to the present.