Why? Because in what he is about to describe, the veil is surely so transparent / That passing through it is an easy thing.
Reality is always here -- where else? -- just a few psychrons away in the space of your own pneurology. The distance between one world and another cannot be measured with the crude instruments of science. To attempt to do so is like looking for the boundary between the Dreamer and the dream. The two are distinct but inseparable.
Dante sees a "company of noble spirits," facing east with palms lifted upwards, and with "eyes intent upon the heavenly spheres." Clearly they are actively oriented to the vertical; the open hands signify an attitude of (o). Then,
Emerging and descending from above / I saw two angels bearing flaming swords. One of them descends all the way down, settling on the embankment across the way. Woo hoo! Vertical I-AMissaries!
Dante looks at the girl with the sun in her eyes, and is "dazzled by [the] excessive light" -- which immediately calls to mind the Transfiguration, in which Jesus' face "shone like the sun."
Sordello says that they are sent by Mother Mary, speaking words of wisdom and protecting against the serpents that surely come out at nightfall. Just like here, coldblooded reptiles emerge from the brush to warm themselves with the remains of the day.
Dante sees another familiar face and explains the situation to him: he has arrived here "by way of the sad regions"; he is not actually dead, but "still within the first life." However, "by this journeying, I earn the other."
Here again, Dante is giving us a BIG HINT of what this poem is all about. But his interlocutors are astonished to hear this.
Just then Dante is distracted by three flaming torches located in the southern sky. But just this morning, in that very same spot, were four brilliant stars that are now below the horizon. What gives?
Before we can find out, everyone does a spit take (remember, it's a comedy), because right over THERE is the serpent! And not just any serpent, but one that looks suspiciously similar to the one who "offered Eve the bitter food."
Now we're really in the thick of it. The cosmic veil has been lifted, behind which we see a celestial spark in the park in the dark, and now that rake of a snake who spake is awake!
But then a couple of celestial hawks -- i.e., the angels -- move across the sky, causing the serpent to flee. Of note, the snake only hears the rustling of wings, and this is sufficient to send him back under cover of darkness.
Surely the angel/birds represent the higher consciousness through which we are vigilant, and with which we "watch and pray." For there are beasts hiding within our garden, and which require a kind of night vision in order to see them. But once seen, they scatter. They are unable to endure the glance -- the glancing blow -- from on high.
After this episode, Dante is able to safely fall off to sleep and even to dream, where free to wander farther from the flesh / and less held fast by cares, our intellect's / envisionings become almost divine.
The dream is an obvious transformation of the events of the evening, involving an eagle patrolling the sky, ready to swoop down on its prey. Note that this eagle can only descend not ascend, for its claws refuse to carry upward any prey.
But it then snatches up Dante himself -- who is not prey -- lifting him toward the sun. Both he and the eagle are scorched by the flames, to such an extent that he is awakened from his slumber, terrified and "cold as ice."
Clearly, as much as Vanderleun protests, Dante cannot just skip purgatory and go straight to paradise. Many things remain to be burned and purified, but this is a controlled burn, not an uncontrolled forest fire -- not a raging inferno, as it were.
It is like the difference between undergoing psychotherapy in order to patiently process unconscious material, vs. dropping acid and being swallowed up into the unconscious, winner take all.
But in an interesting plot twist, it turns out that Dante was visited in his sleep by an angel, "Lucia," who took him up toward the entrance of purgatory proper. Luc-ia is Light, of course, but now I am out of time, so you figure it out. Hint: the Walrus was Paul.
Climb in the back with your head in the clouds, and you're gone.