Todd carries the knife throughout the novel. He originally gets it from Ben when he sends Todd out of Prentisstown. Immediately, the knife assumes ominous connotations. If used, it will always be an instrument of violence.

Todd thinks that, “A knife ain’t just a thing…It’s a choice, it’s something you do. A knife says yes or no, cut or not, die or don’t. A knife takes a decision out of your hand and puts it in the world and it never goes back again” (84).

The knife represents several things, depending on how people use it. As the mayor tells Davy, “A knife is only as good as the one who wields it” (258). Until Todd uses it to kill the Spackle, the knife symbolizes Todd’s innocence and impending growth. After he kills the Spackle, the knife is a symbol of his guilt, rage, and coming of age as a killer. At the end of the novel, Viola kills Aaron with the knife, saving their lives.

Noise is the name people on New World give to other peoples’ thoughts. Noise symbolizes the absence of privacy on New World, the consequences of information overload, and the chaotic nature of the human mind.