In chapter 29, we see each character’s reaction to Bob Ewell’s death and what should be done about Boo Radley, who killed Ewell defending Scout.
Atticus originally thinks that Jem killed Ewell. Scout notices how upset Atticus is.
His age was beginning to show, his one sign of inner turmoil, the strong line of his jaw melted a little, one became aware of telltale creases forming under his ears, one noticed not his jet-black hair but the gray patches growing at his temples. (chapter 29)
Atticus is clearly upset because his children were attached, and we learn later that he thinks Jem did it. When Atticus describes Ewell, he says he was “out of his mind” and Tate says that he was drunk, but not crazy. Atticus responds:
Atticus shook his head. “I can’t conceive of a man who’d—” (chapter 29)
Even though Atticus is a lawyer and has seen some bad things, he still did not think that Ewell was capable of murdering children. This demonstrates that Atticus does look for the good in people, and still expects the best of them. During the trial, he tried to sympathize with Bob Ewell. He learns that he was wrong.
Atticus said, “I thought he got it all out of him the day he threatened me. Even if he hadn’t, I thought he’d come after me.” (chapter 29)
The difference between Atticus’s perceptions and Tate’s are telling. The sheriff has seen the same things Atticus has, but does not remain as optimistic about human nature.