"""A cask by losing centre-piece or cant
Was never shattered so, as I saw one
Rent from the chin to where one breaketh wind.
Between his legs were hanging down his entrails;
His heart was visible, and the dismal sack
That maketh excrement of what is eaten.
While I was all absorbed in seeing him,
He looked at me, and opened with his hands
His bosom, saying: "See now how I rend me;
How mutilated, see, is Mahomet;
In front of me doth Ali weeping go,
Cleft in the face from forelock unto chin;
And all the others whom thou here beholdest,
Disseminators of scandal and of schism
While living were, and therefore are cleft thus.
A devil is behind here, who doth cleave us
Thus cruelly, unto the falchion's edge
Putting again each one of all this ream,
When we have gone around the doleful road;
By reason that our wounds are closed again
Ere any one in front of him repass."""
- Dante's Inferno, Canto 28
Dante may have placed Mohammed, ""seminator di scandalo e di scisma,""
in a fairly nasty section of Hell (though only two doors away from crafty Ulysses and his muscle-man assistant Diomedes...masters of fraud), yet, interestingly enough, Dante envisions Avicenna (Ibn Sina) and Averroes (Ibn Rushd) in merely the first circle of the inferno (aka Limbo, though also interpreted as something like Elysium). Thus the great muslim clerics, like Aristotle ["the Philosopher" in medieval times], still may perceive the light of Reason, and while they have not joined the blessed in Los Cielos, they have it fairly easy, in terms of the afterlife, compared to the Prophet, Ulysses, or, Osiris Forbid, Caiaphas, or the rebels in Lucifer's gaping mouth.
However spooky or supernatural Dante's visions seem, the circles of Hell ("giros", or for Yeats, gyres, usually depicted as a vortex) do not lack a certain rational structure. Humans distinguish between levels of crime, for an obvious instance. A pickpocket or prostitute is not a Pol pot (..bapticks or Kalvinicks say otherwise). When some university philosophaster alludes to supervenience, or set theory, think...gyres; though the ancients (at least the more platonic sorts--) considered Justice an abstract entity, along with mathematical and logical entities. Pi, or a perfect circle, or pythagorean theorem do not grow on trees, then neither does the categorical imperative---those who scoff, and prefer to chant naturalism via the whole sick crew--e.g. Darwin, or Marx, Nietzsche, Willard Quine, etc.--- may toss the speculative metaphysics on the bonfire at their own risk (that said, we agree with Bertrand Russell that Aristotle's system, while perhaps useful to natural sciences, mostly befuddled the supreme clarity of the platonic Idea. Dante was more neo-platonist that Ari). .....
Dante probably follows Aquinas in his moderate treatment of the muslim clerics. Averroes, for one, was a scholar, and early scientist and translated Aristotle's logic and other words into Arabic. Avicenna also was influenced by the greek philosophers. Aquinas and other catholic figures of his era attempted to convert muslims (who he refers to as gentiles) to Christianity--(protestantism of course does not appear until 1500 or so). In this post-Darwinian, post-Freudian age, most modern humans probably consider Dante's Inferno an old wives' tale, or merely stale metaphor--if they consider it at all-- yet there was a method to the madness of the scribes. Hell might be a "possible world" (especially given all the talk of separate dimensions, quantum parallelism, etc).
Aquinas on Mohammedism (from the Summa contra Gentiles): """On the other hand, those who founded sects committed to erroneous doctrines proceeded in a way that is opposite to this, The point is clear in the case of Muhammad. He seduced the people by promises of carnal pleasure to which the concupiscence of the flesh goads us. His teaching also contained precepts that were in conformity with his promises, and he gave free rein to carnal pleasure. In all this, as is not unexpected, he was obeyed by carnal men. As for proofs of the truth of his doctrine, he brought forward only such as could be grasped by the natural ability of anyone with a very modest wisdom. Indeed, the truths that he taught he mingled with many fables and with doctrines of the greatest falsity. He did not bring forth any signs produced in a supernatural way, which alone fittingly gives witness to divine inspiration; for a visible action that can be only divine reveals an invisibly inspired teacher of truth. On the contrary, Muhammad said that he was sent in the power of his arms—which are signs not lacking even to robbers and tyrants. What is more, no wise men, men trained in things divine and human, believed in him from the beginning, Those who believed in him were brutal men and desert wanderers, utterly ignorant of all divine teaching, through whose numbers Muhammad forced others to become his followers by the violence of his arms. Nor do divine pronouncements on the part of preceding prophets offer him any witness. On the contrary, he perverts almost all the testimonies of the Old and New Testaments by making them into fabrications of his own, as can be. seen by anyone who examines his law. It was, therefore, a shrewd decision on his part to forbid his followers to read the Old and New Testaments, lest these books convict him of falsity. It is thus clear that those who place any faith in his words believe foolishly."""