The key events in To Kill a Mockingbird are driven by the undercurrent of prejudice that runs through Maycomb. The most obvious victim of prejudice is Tom Robinson, the black man falsely accused of raping a white woman. Tom’s accuser, Mayella Ewell, is a victim of Maycomb’s prejudice herself; her entire family is viewed as “trash” by the rest of the town. Indeed, Bob Ewell’s persecution of Tom is clearly driven by a desire to bolster his own pride by asserting power over the only group in Maycomb with less social status than the Ewells. That Tom’s conviction is all but assured despite the obvious inaccuracies and impossibilities of Mayella’s accusation illustrates the depth of racism in the town. Though Scout is firmly entrenched in the white world of Maycomb, we get a small glimpse of life for Maycomb’s black community when Scout visits Calpurnia’s run-down church. The visit is marred by a confrontation between Calpurnia and Lula, who argue over whether the children should be allowed to come to a black church. Though the rest of the church is welcoming, Lula’s anger at their presence speaks to the inherent unfairness of the situation: the white Finches—while well-meaning—may enter and leave both black and white spaces freely, a luxury that Lula and the other black people in Maycomb do not possess. The rampant racism in Maycomb eventually bleeds into the personal lives of the Finch family as they face significant social backlash when Atticus becomes Tom Robinson’s defense attorney. Scout and Jem witness prejudice up close again when their Aunt Alexandra comes to visit. Alexandra urges Atticus to fire Calpurnia and teach Jem and Scout about the importance of heritage and class. While many citizens of Maycomb hold strong racist and classist assumptions like Alexandra does, they are contrasted with characters like Atticus and Miss Maudie, who choose to judge people based on their character, rather than their background or race. This is a lesson that both Scout and Jem learn first-hand through their interactions with Boo Radley. Though they initially fear Boo due to his obscurity and the rumors about him in town, the children come to realize that he has been a victim of prejudice; instead of trying to understand him, the townspeople have solidified his outsider status.
A major lesson Scout and Jem learn over the course of the novel is that people cannot be written off as good or evil. At the beginning of the story, Scout and Jem innocently assume that most of the people in Maycomb are objectively “good,” but this assumption is soon challenged by the evil and hypocrisy they witness during Tom Robinson’s trial. Aided by Atticus, Scout and Jem come to realize that while not everyone in their lives is perfectly moral, that does not mean that these people are irredeemably “evil.” One example is Mrs. Dubose, “the meanest old woman who ever lived,” who regularly yells abuse at Jem and Scout as they walk by her house. It is only after her death that they learn that she was struggling to overcome a morphine addiction, determined to die on her own terms. The revelation of Mrs. Dubose’s unexpected bravery makes Jem and Scout more empathetic and slower to judge the people around them. From the very beginning, Atticus works to convince Scout of the potential for good in people despite their “blind spots.” His optimism is borne out when Scout is able to successfully dispel a lynch mob by making innocent small talk with its leader. These encounters broaden Scout’s worldview, and we see the results of this transformation when Scout observes Mayella Ewell at the trial. Though she believes that Mayella’s actions are reprehensible, she is also able to recognize that Mayella Ewell has lived a hard, sad life: “Mayella Ewell must have been the loneliest person in the world.” Scout’s strengthened empathy allows her to see flawed individuals like Mayella as nuanced and complex people who are worthy of human dignity and understanding despite having done terrible things. By the end of the novel, Atticus’s insistence that his children approach others from a place of compassion and empathy has successfully prepared Scout and Jem to confront the evils of mankind without losing their faith in the goodness of humanity.
To Kill a Mockingbird is, at its heart, an examination of the ways in which innocence is impacted by society. We follow Scout and Jem as they journey away from the world of childhood ignorance to come to terms with the adult realities that surround them. Atticus’s decision to defend Tom Robinson initiates this loss of innocence, exposing the children to the ugly racism of their neighbors. Tom’s conviction and the resulting realization that truth and goodness do not always triumph over lies are particularly difficult for Jem to accept. The trial is an awakening, not only for the children, but also for the town as well. Just as the children must grow up and confront the adult world, the trial forces the town into a confrontation with its own deep prejudices. While Scout and Jem's coming of age is a difficult transition, their loss of innocence makes them more perceptive and sympathetic to the people around them. In the beginning of the novel, Scout and Jem are too naive to realize that their Boo Radley game might be hurtful; Boo Radley is merely a “malevolent phantom” to the children—a monster rather than a person. As their awareness of the intolerance and hypocrisy in Maycomb grows, the children realize that Boo himself has been a victim of prejudice that they, until recently, held as well. Though Jem and Scout are both deeply affected by the events in Maycomb, Atticus’s guidance ensures that they emerge from their loss of innocence with their faith in humanity intact. To Kill a Mockingbird also explores the ways in which the innocent may be unjustly injured by prejudice: racism denies Tom Robinson his legal innocence, while cruel rumors turn Boo Radley into a social pariah. Both Tom and Boo are living representations of the symbolic “mockingbird,” an innocent creature whose songs bring beauty to the world. Tom and Boo are not only innocent of the accusations hurled against them, but they are also fundamentally good people; Tom goes out of his way to help Mayella Ewell, whom he feels pity for, while Boo Radley braves the world outside his home to aid Jem and Scout. Ultimately, the reader understands that just as Miss Maudie says it is “a sin to kill a mockingbird,” it is a terrible sin that the society of Maycomb has treated these two innocent men so unjustly.