In the beginning of the story Montag was oblivious to anything that had to deal with emotions and feelings. Montag was in the middle of burning books and houses down and feeling nothing toward it. It was actually said that he was happy that he got to burn down the books.
He later met this one girl named Clarisse and she thought different then everyone else and she had more in depth emotions then everyone else. She was telling Montag about a time where people read books for fun and obtain knowledge and Montag doesn't believe that and thinks she is talking nonsense. At the end of their walk she asks Montag if he is happy and Montag responds with him saying he is happy why wouldnt he be happy? and that ends the conversation.
When Clarisse asked Montag if he was happy and this really got him thinking if he was really happy or not. He wants to believe that he is happy but he doesn't really know if he is or not. We later find out that he has a book and this goes against all of the rules. He is becoming guilty of the fact that he owns a book and he is starting to regret his decision of owning a book.
He wants to figure out how to remember and how to obtain the knowledge of the books he is reading. He remembers a time where he met a professor that told him about books.