A sister can be seen as someone who is both ourselves and very much not ourselves — a special kind of double.

The line frames sisterhood as an intimate relationship built on simultaneity: profound identification (“ourselves”) alongside irreducible difference (“not ourselves”). Calling a sister a “special kind of double” suggests a mirror that does not merely reflect but refracts—someone close enough to share origins, family history, and formative experiences, yet separate enough to challenge, contradict, and reveal hidden aspects of the self. The “double” also hints at Morrison’s recurring interest in doubleness and divided identity: how selves are shaped through relational bonds, and how kinship can be both sustaining and unsettling. The quote elevates sisterhood beyond sentimentality into a complex psychological and ethical space where self-knowledge is negotiated through another person.