Fiction can be more influential than Scripture in shaping popular theology. Dante and Milton are two examples. In general, I think that Dante’s vision of the afterlife has been more influential than Milton’s. This is especially the case in his depiction of hell—which is more memorable than his depiction of Purgatory or Paradise.
However, most English-speakers don’t read Medieval Italian, so in some ways Milton’s vision may have been more influential for English-speaking Christians. Of course, he came long after Dante, so Dante’s vision had more time to sink in. And first impressions tend to stick.
Also, I doubt contemporary Christians read Milton as often as they used to. They prefer C. S. Lewis or Tolkien.
Dante situates his epic poem in heaven, hell, and Purgatory, while Milton situates his epic poem in heaven, hell, and earth. So both poems are set in three major localities.
With Dante, it’s a progression from to the next. One at a time. With Milton, they alternate.
Dante’s version of heaven is very ethereal, while Milton’s version of heaven is very earthly. There’s a sense in which Milton’s version of heaven is earthier than his version of earth. For his depiction of the Eden is quite artificial, more like a theme park or formal garden. Milton didn’t have much of an eye for nature. He was an urbanite: a man of books and letters.
Milton’s version of heaven is like a scene from Clash of the Titans. A very Jovian God. More like Zeus than Yahweh.
Dante’s version of heaven is a masterpiece of scientific and theological synthesis: Thomism, Aristotelian physics, and Ptolemaic astronomy fused into one. A work of genius. Still, it can’t rise above the raw materials from which it’s drawn.
Both Dante and Milton have very detailed depictions of hell. I expect this is driven by the need for dramatic parity. If you’re going to write an epic poem about heaven and hell, then there needs to be some proportional balance between the two. In its way, hell needs to be as monumental as heaven to function as a dramatic counterweight.
Dante’s hell is highly compartmentalized. The space is divided and subdivided, like a hotel with many rooms or an office with many cubicles. Very ergonomic. A model of efficient penology.
By contrast, Milton’s version of hell is more like a dimly-lit warehouse or airport hanger. Vast stretches of empty space. Boundless.
There’s nothing very scary about Milton’s version of hell. Perhaps this reflects the outlook of a very bookish Englishman. Nothing better to do on a rainy day than sit in front of a fireplace with a good book.
With his urban esthetic, Milton likes to see big spaces subdivided into rooms with walls and doors. He’s ill at ease with vast expanses of nothingness. If Dante’s version of hell is often claustrophobic, Milton’s version of hell is agoraphobic.
Maybe he’s gripped by Pascal’s fear of the infinite. To be lost—because everywhere is nowhere in particular.
In Milton’s hell, the damned seem to have the run of the place. They make their own rules. By contrast, Dante ‘s damned are assigned to their infernal niches.
The problem with these depictions of heaven and hell is their lack of Scriptural mooring. They don’t represent a logical extrapolation from Scripture. Indeed, they’re often at odds with Scripture.
From a scriptural standpoint, there’s no reason to assume that hell will be a grandiose affair. For all we know, hell may be ticky-tacky place where nothing works. Leaky ceilings. Peeling paint. Drafty rooms. Barking dogs. Broken appliances. With Satan as the slumlord.
Likewise, the Biblical doctrine of the final state of the saints is far more down-to-earth than Dante’s disembodied conception. The resurrection of the just. The renewal of the earth.