fire is symbolic

In Guy Montag's community, free thinking can be compared to fire. In some forms, or places, it's damaging and destructive and in other forms it serves a good purpose: like the fire in the sun warms Montag. In Montag's community free thinking is destructive and shouldn't be messed with. In the land outside Montag's city, free thinking is encouraged because it gives hope, light, that the future would encourage knowledge again.