In Part Two, "The Sieve and the Sand," of Ray Bradbury's science fiction classic, Fahrenheit 451, some major ideas or themes are being presented in this section that were not in evidence in Part One.
In Part One, Guy Montag was a fireman: someone who started fires rather than putting them out—in his society. He loved burning houses of people who owned books. He never thought about what he was doing. Then Montag meets Clarisse McClellan, a young woman who questions everything, and watches and notices the world around her. Montag thinks she is strange at first, but her notions affect him to the point that he changes: seeing the world—and his place in it— at last. He was a casual observer before; now Montag is a participant in his world—while his wife Mildred is completely apathetic.
At the start of Part Two, the TVs ("parlor walls") are off, and Montag is reading to his wife. Without her "shows" and the "family" she considers them to be, she is completely lost.
The parlor was dead and Mildred kept peering in at it with a blank expression...
She is terrified that if they are caught with books, her house and her "family" could be destroyed. Mildred is completely unrealistic and out of touch with reality: she believes the people (the actors) on these TV shows are her family. This is ridiculous. They are not real: they act as society dictates, probably with no more sense of self in their reality than Mildred and her friends have in theirs.
Montag has been completely transformed by his meetings with Clarisse. She opened his eyes to the world: to dew on the grass, the man in the moon, the purpose of firemen hundreds of years before, etc. While Clarisse seems extremely unusual—even strange—to Montag, in Part Two he finds himself acting and thinking more like Clarisse. He notices the sound of the rain outside, something he would never have heard before. He questions the concept of friendship, something he seems to know nothing about. He reads...
We cannot tell the precise moment when friendship is formed. As in filling a vessel drop by drop, there is at last a drop which makes it run over; so in a series of kindnesses there is at last one which makes the heart run over.
Montag ponders this description and wonders if he had a friendship with Clarisse? One question leads to another: when did bombers in the sky become commonplace? Is it true that others in the world starve while he and his countrymen do not? Montag is developing a social conscience and original thoughts; no longer will he accept what the government says as the truth. He is also becoming dangerous because of his questions and new curiosity.
Montag calls Faber, taking his first public step toward rebellion. He asks, how many copies of the Bible are in existence? How many of Shakespeare? Faber is frightened and hangs up, but Montag will never be passive again. Before, he lived life in a haze—so much so that he was amazed when Clarisse told him he was unhappy (in Part One), and she was sad, too, that he wasn't in love—things he had never realized.
Mildred announces that the women are coming over—for more mindless entertainment it seems. However, Montag is filled with wonder. He may have the only remaining copy of the Bible in their area. He must return a book, but how does he choose?
Mr. Jefferson? Mr. Thoreau? Which is least valuable?
Montag is learning that all books are valuable—difficult knowledge in his line of work.