But the real drama of the canticle is literally cosmic: It develops out of the tension between a perfect heaven above and a very imperfect world here below. After more than 10 years in exile, Dante was an expert on human imperfection. And even though he'd seen one after another of his political hopes crushed under the steel toe of history, he never gave up on the ideal of earthly justice. (In the Monarchia, written around the same time as the Paradiso, he argued that "the world is ordered in the best possible way when justice is at its most potent.") This is why, despite all their professed camaraderie and contentment, the souls of the blessed can't stop talking about what's happening on earth. The folly of the living brings them repeatedly to rage, as when St. Peter says of Pope Boniface VIII: "He … has made my tomb a sewer of blood and filth." Dante himself is not shy about joining in the general indignation. Looking down from the eighth sphere of heaven, he sees only "the little patch of earth that makes us so fierce."
The most famous example of the drama forged from the contrast between heaven and earth occurs in the heaven of the sun. There Dante meets St. Thomas Aquinas and St. Bonaventure, the two great medieval theologians, both of whom belonged to mendicant religious orders. The friars take turns narrating the hagiographies of the orders' founders, but with a twist: Thomas (a Dominican) tells the story of St. Francis, and Bonaventure (a Franciscan) tells the story of St. Dominic. After praising St. Francis, Thomas goes on to denounce his own order, complaining that the number of living Dominicans who have stayed true to their founder "are so few/ that a tiny piece of cloth can furnish all their cowls." (Bonaventure delivers a similar denunciation of the Franciscans.) Thomas and Bonaventure are each liberal in their praise, but to understand just how extraordinary their double gesture is, we have to consider it against the backdrop of life on earth, where the two orders were often in competition.
In a sense, the cosmic drama of the Paradiso inverts the dramatic irony that's so attractive in the Inferno. Dante's hell flatters us: It allows us to stand in judgment, to delight in the friction between what we know and what the damned don't—to see things, in other words, from the perspective of God. Paradiso, however, puts us back in our place. Though the poet labors mightily to "show the merest shadow/ of the blessèd kingdom stamped within my mind," he never lets us forget that it is only a shadow. Once we follow him to heaven, it's we who lack the inside information, we who stand on the wrong end of the irony. Previously we judged hell; now heaven judges us.
The idea of a heaven that stands in such uneasy tension with earth is what gives the Paradiso its dramatic power, but it is also what makes Paradiso so alien to our sensibilities. As Adam Kirsch argued several years ago, contemporary writers like Alice Sebold and Mitch Albom treat heaven as essentially therapeutic, "a chance to get our inner lives right at last." The way these writers see heaven echoes the way they think about literature: Sebold says that "part of my work is motivated by wanting to give us all permission to feel what we feel and not judge ourselves so harshly for it." For the same reasons that he looked to heaven for justice rather than therapy, Dante rejected this comforting view of literature. He wanted his poem to save your soul, not to salve it.