The anxiety of facing a monster or psychopath is of a different kind than the inability to know something for sure. For me, uncertainty possesses its own kind of unsettling. Narrative has traditionally insisted on closure, but more and more I’m suspicious of cause and effect, motivations, and neatness in stories. I encounter many readers who not only get frustrated but sometimes downright angry when things are left unhinged. I suspect those reactions are partially about readerly expectations, but also a kind of defense against not-knowing.