As a novel of ideas, Heaven makes the case for compelling yet conflicting views of the world. As a coming-of-age story, it also makes the tension between these philosophies part of the internal conflict that allows its central character to mature.

The first worldview is represented by Kojima, who views human frailty as something to be understood and appreciated. In Chapter 7, she refers to the “beautiful weakness” she feels responsible for protecting, which puts many of her actions into perspective. Kojima maintains a messy appearance that her classmates mock, assuming that it reflects her poverty and class; however, Kojima’s family is relatively affluent. She also adopts a defiant attitude in the face of her bullies: Though she does not stand up to them outright, she welcomes their harassment as if she understands their need to inflict it. Kojima understands that the narrator’s lazy eye makes him vulnerable, and she tells him that he must protect it. All of Kojima’s appeals for solidarity and understanding fundamentally stem from her witnessing her father’s loneliness. Having been rejected by Kojima’s mother and after losing custody of Kojima, her father is forced to live out his days working as a driver to pay off his business debts.