In To Kill a Mockingbird, how does Jem evolve through out the book
Jem in many ways has a coming-of-age experience that is much harder to cope with and manage than Scout's coming-of-age. He witnesses an act of injustice just as he is going through puberty, and it is clear that what he sees happening to Tom Robinson clearly shakes his belief in humanity and in justice in general. Note how he responds to what happens to Tom Robinson in Chapter 22, and how Atticus replies to him:
"Atticus--" said Jem bleakly.
He turned in the doorway. "What, son?"
"How could they do it, how could they?"
"I don't know, but they did it. They've done it before and they did it tonight and they'll do it again and when they do it – seems that only children weep. Good night."
Jem is left shattered by the experience, yet by the end of the novel, there does seem to be some hope that he can recover from this loss of innocence. In Chapter 25, for example, he prevents Scout from killing a bug because it had done nothing to harm her. Presumably, having witnessed the injustice experienced by Tom Robinson, he seeks to uphold justice in his own way. In addition, by the end of the story, Jem shows in his relationship with Boo Radley that he is able to move beyond childish fears and act like an adult, giving the reader hope that he will reach adulthood in tact. Jem's massive change in the novel therefore is from childhood to adulthood, having experienced some of the massive complexities of adult life.