Whenever there is an analysis of a particular character in a work of literature, there will always be different approaches as to which scenes or moments were essential to the character's development. This is especially so with Montag. Many different scenes can be used to illuminate his path to redemption from "book- burner" to a "living book." In my mind, the key is to find moments where it is evident that some change in thought is evident. Being able to find those moments where Montag is able to reflect about the world and his place in it are the critical instances where Montag's path to redemption is evident.
I think that one particular scene that shows this evolution would have to be his interactions with Clarisse. When Clarisse asks him the fundamental question of whether or not he is happy, Montag engages in critical thought and reflection:
Of course I'm happy. What does she think? I'm not? he asked the quiet rooms. He stood looking up at the ventilator grille in the hall and suddenly remembered that something lay hidden behind the grille, something that seemed to peer down at him now. He moved his eyes quickly away. What a strange meeting on a strange night. He remembered nothing like it save one afternoon a year ago when he had met an old man in the park and they had talked ....
It is clear that Montag's path to redemption is laid out in front of him. He is no longer thinking about how he needs to support the existing system. Rather, the result of Clarisse's conversation with him is that Montag is thinking about how things might be, or how they can be. As Granger will help him understand by the end of the novel, the Status Quo is not to be worshipped, but rather undermined. The reflective tone within "Of course I'm happy," reeks of someone who is trying to convince themselves of something that might not be true. At the same time, the projection into both the past and the conditional tenses are reflective of how Montag is changing, moving along the path towards his eventual redemption. Bradbury makes clear that the only way individuals are able to embrace a condition of liberation is through questioning and self- doubt, elements that Montag shows in this instant. These elements demonstrate themselves later on when Clarisse's absence is felt:
And then, Clarisse was gone. He didn't know what there was about the afternoon, but it was not seeing her somewhere in the world. The lawn was empty, the trees empty, the street empty, and while at first he did not even know he missed her or was even looking for her, the fact was that by the time he reached the subway, there were vague stirrings of un-ease in him.
Clarisse has made Montag think about the world and his place in it. As a consequence, interacting with her has helped him along his path towards redemption.
The eventual questioning of Montag's place in the world and the world itself is a significant part of why he repudiates his life as a book burner This is seen when he observes the manner in which his wife is tended to when she is ill. When Mildred overdoes on sleeping pills, Montag is struck by the banal way she is addressed, and the impersonal manner that dominates it:
There are too many of us, he thought. There are billions of us and that's too many. Nobody knows anyone. Strangers come and violate you. Strangers come and cut your heart out. Strangers come and take your blood. Good God, who were those men? I never saw them before in my life!
Montag is one who works for "the system." Yet, it is at this moment when he can no longer be an apologist for it. Montag recognizes that the structure which envelops him is a flawed one, something that must be addressed in the most direct of terms. Montag is direct, almost embracing Clarisse's observation, about the nature of being in the world. He fundamentally feels that he can no longer excuse what is happening in the system. At the same time, he recognizes clearly that there is something wrong in a world where "Strangers come and take out your blood." At this moment, Montag is questioning the world and his place in it. The result is that he no longer seeks to conform to the expectations of a world where only "strangers" seem to exist.
Clarisse, directly, and Mildred, indirectly, end up demonstrating to Montag what should not be. Granger is able to articulate to Montag a vision of what can be. As Montag is able to make progress on his path to redemption, the movement is strengthened with the physical and intellectual shelter he provides to Montag at the end of the novel:
Everyone must leave something behind when he dies, my grandfather said. A child or a book or a painting or a house or a wall built or a pair of shoes made. Or a garden planted. Something your hand touched some way so your soul has somewhere to go when you die, and when people look at that tree or that flower you planted, you're there. It doesn't matter what you do, he said, so long as you change something from the way it was before you touched it into something that's like you after you take your hands away.
Granger's unwillingness to accept the Status Quo is something he communicates to Montag. In embracing the idea that the function of the human being is leaving "something behind," it helps to underscore Montag's transformation from a book burner to a living book. Montag is able to recognize what it is he needs to do and why it is important for him to do it. He is able to understand that his path towards redemption lies in embracing what can be and what might be as opposed to what is. For Montag, being able to embrace the experiences, words, and actions of those around him help him to progress on his spiritual path towards redemption, one where a book burner becomes a living book, where an apologist for the system ends up subverting it.