What fallacies are used in Fahrenheit 451? Give examples.

A fallacy is an instance of false logic, something that on the surface makes sense, but when examined a little further, really doesn't make sense at all.
The society of this novel is built on the fallacy that if everyone is forced to conform and not allowed to think, people will be happy. As true believer Beatty explains, people themselves signaled they wanted to be ignorant and happy by choosing silly magazines and television shows over serious reading even before the government banned books. He talks about how smart kids used to be bullied mercilessly in school. He defends the society they live in as a way to spare people who are different from being tormented.
Of course, as Millie's case show, forcing everyone to life in an inane, conformist world emptied of genuine thought does not make people happy. Millie becomes so miserable she tries to kill herself.
Montag also learns that it is a fallacy to think that saving books themselves means anything. He learns that it is the knowledge within the books and what people do with it that matters.

Several types of fallacies appear in the novel. They include pathetic fallacy and several types of logical fallacy.
Pathetic fallacy, attributing emotion to inanimate objects, is shown by Montag toward the Mechanical Hound, which is a programmed machine. "It doesn't like me," he tells Beatty.
The firemen and the propaganda on TV use logical fallacies to justify burning books and other repressive policies. After Clarisse dies, Beatty tells Montag that people are better off ignorant. He uses numerous examples of unsound reasoning in circular arguments, summarizing these metaphorically: "If you don't want a house built, hide the nails and wood." He equates being deceived to happiness.

The firemen are taught to believe that their job has always been to put out fires. When Montag, inspired by talking with Clarisse, asks about this, the others laugh at him. They refer to their rule book, which states that fire companies were established in 1790 to burn books (first fireman, Benjamin Franklin). This is a fallacy of false authority, as the source is invented and unreliable.