Canto XIV -- The Second Cornice: The Rein of Envy
Dante begins this canto with an example of two penitent who are developing an understanding of caritas, for they are not allowed to envy the good fortune of someone who walks their ledge without his eyes sewn shut, and they demonstrate this when the second to speak offers to the first because of his proximity the right to ask Dante about himself but prefaces it with the advice to "put it in a way/ that won't offend him. Take a careful tone" (4-5). Dante learns they are Guido del Duca and Rinier da Calboli di Forli though Guido is the main talker, suddenly gifted with a flash of insight relevant to both Rinier and to Dante. After the general harangue against Italian corruption, Guido continues his crying and the poets take their leave, leaving little action having happened in the canto. 
The big event is the sudden thunderclap that is the rein of envy, providing two strong examples of how destructive a lack of caritas is . . . and this brings us to Pope, who, serving as a foil for Dante, will help us understand what is meant by half full or half empty. Pope is worthwhile in this canto for his articulation of the philosophy of the ruling passion:
Pleasures are ever in our hands or eyes,
And when in act they cease, in prospect, rise:
Present to grasp, and future still to find,
The whole employ of body and of mind.
All spread their charms, but charm not all alike;
On diff'rent senses diff'rent objects strike;
Hence diff'rent passions more or less inflame,
As strong or weak, the organs of the frame;
And hence one master passion in the breast,
Like Aaron's serpent, swallows up the rest (II, iii, 123-32).
As we've witnessed in hell and now on these cornices, the idea of the ruling passion precedes Pope by at least as far as Dante, but Pope puts a twist on it -- one passion, he insists, drives all the others so that all of a person's motivations can be found rooted in a single predisposition that does not necessarily have a contiguous relationship to the other passions. In Pope, then, the passions aren't weighted. While it is true that in the Inferno each circle is archetypal of a ruling passion -- e.g., Ciacco can only be in one place as his state of being, his ruling proclivity or disposition, dictates, the sinners of both hell and purgatory have to be placed in contiguous relation to the sins or vices on which they are based and toward which they lead. Dante, unlike Pope, then, is entirely relational, and the layout of hell as a relational schemata should start to make more sense to us on this mountain.
In the Purgatorio, moreover, we have the sense of distributed guilt in that heavenbound souls must experience purification of all vices in their journey toward all virtues. In the course of the penitents' progression, they may spend time on every cornice though they remain on some longer than on others. We learned in the previous canto that Dante knows he'll share Od'risi's fate, and he also knows that his eyes will be taken from him only a very short time (Purg. XIII, 133-35). In effect, he'll spend time on both ledges since he has within him both vices. Pride does not subsume envy but coexists with it. The point not to be missed, furthermore, is that guilt is weighted in Dante, so Dante's ruling passions have to be different from those of modernity -- they represent more or less the distance that humanity puts between itself and God.
In this comparison with Pope, then, we find the key to Dante, for just as Pope argues that "nature gives us (let it check our pride)/ The virtue nearest to our vice allied: Reason the bias turns to good from ill, . . . The same ambition can destroy or save,/ And makes a patriot as it makes a knave" (195-97, 201-02), we can argue that these vices exist only in relation to their virtues, and not as opposites of one another. Greater degrees of pride exist in the absence of greater degrees of humility -- it is here that we find the Einstein anecdote posted earlier most useful. Dante's whip and rein, then, are meant not to purify one of pride but to address the deficit of humility -- instead of their being Manichaean constructs like yin and yang, each of these capital vices is only a vice in relation to the absence of its corresponding virtue.
Applying this rule to envy, then, we find that envy is only problematic because of the deficit in caritas (the virtue of which St. Agnes of Bohemia had a great deal), and that is what the penitent are learning while pressed against that bruised wall. It's not that they are being punished for envy; rather, it's that they don't yet have enough caritas to ascend. They are still too "heavy" in their guilt. They yearn, then, (in fact, they pray) for caritas, something that the Dante of La Vita Nuova once more proves he does not possess when the women shame him for his writings that were not in praise of his beloved. He cannot be in Beatrice's presence without swooning, but these women can be, and he must feel sorrow at their good fortune to be oriented toward Beatrice in ways that he is not. Likely, though, I'm grasping at a connection here, for Dante's shame comes in his having written poetry other than that which praised Beatrice, and there is no textual evidence to suggest he envied these women.
S.

