I think that Scout is presented as a force of potential purity and innocence in a world that might be devoid of it. Consider the ending lines of the narrative when Scout speaks to Atticus: “An‘ they chased him ’n‘ never could catch him ’cause they didn’t know what he looked like, an‘ Atticus, when they finally saw him, why he hadn’t done any of those things… Atticus, he was real nice…” Scout is shown to be a force of purity and innocence in the novel because she is so fundamentally different from the world around her. She does not embrace the socially constrictive notions of gender identity. Rather, she is a "tomboy" to a great extent because it is an authentic expression of who she feels she is. Part of her collision with Aunt Alexandria is because Scout does not cling to the socially dictated notions of the good that her aunt does. However, even though both Scout and her Aunt differ on many issues, it is clear that Scout's innocence and purity are evident when she empathizes with her: " ...If Auntie could be a lady at a time like this, so could I." Such compassion out of conscience is a part of the reason Scout is shown to be pure and innocent.
Indeed, Scout does get into scrapes and trouble. Her purity and innocence are not otherworldly. For example, she does succumb to the imagined perception of Boo Radley. However, she is shown to be pure and innocent in how she does not take the form of the world around her. Scout does not absorb the reductive notion of the good that is so much a part of Maycomb. Rather, she is pure and innocent in how she sees people. This is especially so when she embraces and lives Atticus's words of how it is essential to refrain from judgment "until you climb into his skin and walk around in it." This is evident when Scout recognizes that "there's only one kind of folks: folks." When Scout displays her love of reading, it is pure and innocent: "Until I feared I would lose it, I never loved to read. One does not love breathing." Scout is depicted as pure and innocent because it is clear that she sees the world with a transformative vision that identifies what can be as opposed to what is. In this light, her presentation in the novel is one of purity and innocence; she is a spirit of agency in a world of inertia.