We all know this work, by name if not by heart. And yet when I revisited it recently, I was struck by something I’d missed when I first encountered it—not the horror of hell that Dante conjures so vividly, nor the sense of despair that overcomes you as you descend further and further into the realm—but by how the story is, at its core, an allegory of doubt. The narrator, Dante’s stand-in (also named Dante), is almost exactly middle-aged at the narrative’s beginning when he finds himself “midway upon the journey of our life.” And yet as he climbs deeper into hell, he realizes just how little he actually knows—all those years, all that life, and yet he remains in that “dark wood,” the path he had once walked so surely vanished from sight.