Big Brother himself is a looming presence in London in 1984. His image is everywhere, along with an ominous reminder that "Big Brother is watching you." Whether Big Brother physically exists or not is never fully established. It seems certain that he does not, that he is a fabrication of the Party's propagandists. When Winston asks O'Brien if Big Brother actually exists, in the sense that Winston exists, during his torture, O'Brien only replies coldly: "You do not exist." So Big Brother is an example of manipulation on two different levels. First, the constant belief that one is being watched, symbolized by Big Brother, is a major way of maintaining control for the Party. Second, the fact that Big Brother's physical existence is less important than his existence in the minds of the people is an example of the way the Party manipulates the collective and individual psyches of its members, literally creating reality. In a word, it is "doublethink."