What is the significance of The Sieve and the Sand to Fahrenheit 451 as a whole?
How does this section move the story forward,how do we learn more about the characters,and how do the developmeants in this section reveal the authors message?
Several important things are learned in this section. The first is that we finally meet Faber, who had been hinted at in the previous section. We meet him face to face, and with Faber, Montag plans an all-out rebellion against the system. Faber is a crucial catalyst in helping Montag understand just exactly how their society got to be the way that it is. For the first time, Montag's confusion clears, and he feels like he has a plan, and is starting to understand his own unhappiness. So, Montag's character, in this section, goes from bumbling and confused, to clear and confident. He even tries to counteract the shallowness of Mildred and her friends.
In this section, we also learn a lot more about their society. Through Mildred's friends, we see the true deterioration of family and morals, and the total lack of understanding and depth that exists in most people. We see how unequipped people are to deal with real life. Bradbury's themes of mass entertainment being a degradation to society come through much more strongly. The value of reading, thoughts, opinions, and analyzing one's life is brought forward.
I hope that those thoughts help a bit; good luck!