The characters’ relationships with faith and doubt play an essential role in the novel. On the one hand, Nan has a strong faith in God from an early age, and Charles experiences a calling from God leading him to faith. On the other hand, James struggles with his faith in God, and Lily lacks religious faith completely. Throughout the novel, the characters grapple with faith and doubt in different ways, eventually finding their own paths to and definitions of faith.

James and Lily, who struggle with finding faith the most, begin experiencing faith when they learn to use it to create change in others’ lives. James, who starts the novel as an agnostic, grapples with his faith and ultimately discovers faith in social justice. This leads him indirectly to faith in God, helping him define faith through action.

Lily, a staunch atheist with a disdain for religion, goes through an even greater transformation in faith. When Will is diagnosed with autism, Lily refuses to believe that he is incapable of loving her and Charles or of being happy. She becomes determined to help him in any way she can, using her anger and knowledge to drive her. When she finds Dr.