Themes are the fundamental and often universal ideas explored in a literary work.
Fahrenheit 451 doesn’t provide a single, clear explanation of why books are banned in the future. Instead, it suggests that many different factors could combine to create this result. These factors can be broken into two groups: factors that lead to a general lack of interest in reading and factors that make people actively hostile toward books. The novel doesn’t clearly distinguish these two developments. Apparently, they simply support one another.
The first group of factors includes the popularity of competing forms of entertainment such as television and radio. More broadly, Bradbury thinks that the presence of fast cars, loud music, and advertisements creates a lifestyle with too much stimulation in which no one has the time to concentrate. Also, the huge mass of published material is too overwhelming to think about, leading to a society that reads condensed books (which were very popular at the time Bradbury was writing) rather than the real thing.
The second group of factors, those that make people hostile toward books, involves envy. People don’t like to feel inferior to those who have read more than they have. But the novel implies that the most important factor leading to censorship is the objections of special-interest groups and “minorities” to things in books that offend them. Bradbury is careful to refrain from referring specifically to racial minorities—Beatty mentions dog lovers and cat lovers, for instance. The reader can only try to infer which special-interest groups he really has in mind.
As the Afterword to Fahrenheit 451 demonstrates, Bradbury is extremely sensitive to any attempts to restrict his free speech; for instance, he objects strongly to letters he has received suggesting that he revise his treatment of female or black characters. He sees such interventions as essentially hostile and intolerant—as the first step on the road to book burning.
Montag, Faber, and Beatty’s struggle revolves around the tension between knowledge and ignorance. The fireman’s duty is to destroy knowledge and promote ignorance in order to equalize the population and promote sameness. Montag’s encounters with Clarisse, the old woman, and Faber ignite in him the spark of doubt about this approach. His resultant search for knowledge destroys the unquestioning ignorance he used to share with nearly everyone else, and he battles the basic beliefs of his society.