The Party seeks to control everything – past, present, and future. Another effort towards attaining that goal is to control its constituents’ memory. Without memory, the people cannot know the past. Without memory, the Party is able to control history. By controlling the past, the Party also controls the present – because its constituents will accept everything the Party says. In order to control the collective memory of its constituents, the Party forbids its members to keep written records of their lives, and mandates that any photographs or documents be destroyed through "memory holes" placed throughout Oceania. Since memory is unreliable unless corresponding reality may confirm it, over time, reality becomes fuzzy at best, and Party members are soon willing to believe whatever the Party tells them. Thus, the Party manipulates the past in order to control the present, thanks to our ever-failing memory.
Winston explores his memory in an attempt to reconnect with the past because he believes the past holds the answers to the Party’s rise to power in the present. He therefore agrees with the Party’s theory that to control the past is to control the future.