In "Fahrenheit 451" what does fire symbolize in the story thus far?
In the opening pages of the novel, fire is shown as being a powerful force of destruction. Montag, wielding the all-powerful fire, is in the throws of intense joy at the scene of a house burning, of books flapping and shriveling in the intense flames. Fire is a dangerous, awful, fearful thing that when introduced, only represents danger and supression by the government authorities. It represents your entire life being destroyed if you don't conform. Ray Bradbury even describes the kerosene that produces the flames as "venomous" and "poison."
As the novel progresses, and nears it end, fire is still a destructive force, but in a more positive way. It is the force that will destry society, providing Montag and others a fresh start, a chance to rebuild things and make them better, to not make the same mistakes again. It paves the way for goodness, depth, books, thinking, and human connections to be made in people's lives again. Fire, throughout the entire novel is used as a force to destroy; the difference is what is done with that force--to tear down the good things about humanity, or to build them up and encourage them. I hope that helps; good luck!