” We have unlived lives for all sorts of reasons: because we make choices; because society constrains us; because events force our hand; most of all, because we are singular individuals, becoming more so with time. “While growth realizes, it narrows,” Miller writes. “Plural possibilities simmer down.” This is painful, but it’s an odd kind of pain—hypothetical, paradoxical. Even as we regret who we haven’t become, we value who we are. We seem to find meaning in what’s never happened. Our self-portraits use a lot of negative space.