In class we've talked a lot about things that are defined solely by the abscence of something else. I suggested that J Edgar Hoover likes his white room because he knows that black exists, which only makes his room whiter in comparison--that white only exists because black exists. On page 699, Rosemary is speaking about what it was like when Jimmy left the family. "The trick was, the thing was he was not the center of the family when he was here. She was the center, the still center, the strength. Now that he was gone, she could no longer make herself feel still, or especially central. Jimmy was central now.