1984 did a good job going over that. > The past was erased, the erasure was forgotten, the lie became the truth And > Who controls the past,’ ran the Party slogan, ‘controls the future: who controls the present controls the past.’ … > T]he Party member, like the proletarian, tolerates present-day conditions because he has no standards of comparison. He must be cut off from the past, just as he must be cut off from foreign countries, because it is necessary for him to believe that he is better off than his ancestors and that the average level of material comfort is constantly rising … > Within twenty years at most, he reflected, the huge and simple question ‘Was life better before the Revolution than it is now?’ would have ceased once and for all to be answerable. https://www.sparknotes.com/lit/1984/quotes/theme/manipulation-of-history/