The narrator uses these words to introduce Cathy Ames in Chapter 8 of the novel. Throughout the novel, Cathy displays an evil that is so thorough that it borders on implausible, and the narrator makes several attempts to explain and understand Cathy’s existence. He hypothesizes that although Cathy is physically beautiful, she is a “psychic monster,” a being with a mental deformity analogous to others’ external, physical deformities. Later in the novel, the narrator revises his opinion of Cathy and wonders whether he was right in calling her a monster. He seems to become somewhat more sympathetic toward Cathy, musing that “since we cannot know what she wanted, we will never know whether or not she got it.” Indeed, Cathy’s motivations remain a mystery throughout East of Eden, as her schemes seem to have no concrete goal or aim—a problem that critics have singled out in their writings on Steinbeck’s novel.
Wow sparknotes though, spot on; “since we cannot know what she wanted, we will never know whether or not she got it.”
We impose this dual good/evil construct upon the gray mud of natural world.. There’s so much mystery beyond our perception of evil.