There are many themes in Fahrenheit 451, including censorship, government power, collectivism, and individual responsibility. The future society has no individualism; everyone thinks the same things, quotes the same TV shows, and ignores the atrocities committed by government operatives because they serve to keep the status quo. Montag, through Clarisse, discovers how individual thinking is both liberating and terrifying; he wants to know and feel more than his wife Mildred, who is addicted to television, but he also is scared because he can't quantify his new feelings. Chief Beatty explains how society has been engineered to lose their individuality:
"Cram them full of non-combustible data, chock them so damned full of 'facts' they feel stuffed, but absolutely 'brilliant' with information. Then they'll feel they're thinking, they'll get a sense of motion without moving. And they'll be happy, because facts of that sort don't change. Don't give them any slippery stuff like philosophy or sociology to tie things up with. That way lies melancholy."
(Bradbury, Fahrenheit 451, Google Books)
This is accomplished through censorship, the removal of books which contain contradictory opinions and the stifling of intellectualism and free thinking. The government knows that people will rebel if they have the intellectual basis to recognize tyranny, so they ensure that everyone thinks the same way. Through this system, the collective city functions, but human life is meaningless and outside, there is a global war that no citizen cares to think about.