Overtones

Harriet and Margaret represent the presence that is physically there. They can see each other but not each others alternate forms Maggie and Hetty. Margaret cannot see Hetty and Harriet cannot see Maggie. This represents their true inner selves or their true thoughts. Their inner selves do interact with each other. These interactions are usually one ignoring the other. They are too preoccupied with their own problems. I think it could possibly be Harriet and Margaret's choice to not see each other's inner selves. When you think about it, it's the same thing people do everyday. Sometimes we do not want to see people's true identities.