Channeling John Milton . . .

Satan, Sin and Death, c.1792-1808
James Barry (1741‑1806)
The Tate

Over on the Milton List, the scholar Gregory Machacek (Marist College) is attempting to make sense of Milton's allegory of Sin and Death in Book 2 of Paradise Lost by excising it as a late addition (a Miltonic interpolation mixing allegorical and 'historical' figures), so as to see how the poem appeared prior to the allegory's insertion. Greg's editing requires him to cut other lines elsewhere in the poem, but Book 2 is at the center of the issue, as I note:

Here's the crux of Greg's cutting:

From Book 2, omit the material from the second half of line 648 through the first half of line 884. Line 648 should now end "Surprised but with delight" and the new line 649 begin "Satan observed."

Assuming that Greg is right, that the allegorical figures' interaction with Satan was a later addition, the question is "Why?" Why did Milton add it? Actually, there are two questions: 1) why did he need an interpolation, and 2) why did he choose this allegorical interpolation?

(I believe some answers have been broached, so I may be repeating what others have said.)

Milton needed to get the gates of hell opened, but who would be culpable? Not the unfallen angels since they would not disobey. Only someone disobedient could be responsible. But not the locked-in fallen angels, not directly, else there would be no point to locking them in. That would be the adamantine-chains problem writ large. One can see how Milton could have thought:

"I need someone culpable, but it can't be the fallen or the unfallen. Culpable . . . hmmm . . . why not 'sin' itself? It's the 'key' to getting into hell. So, sin can open the gates. Or better, Sin herself with a key. Culpability write large! But she has to be allegorical, though I'll still need to 'explain' her presence. Satan was the first to sin, so Sin is his conception, as I've already implied in the line 'Deep malice thence conceiving.' Ah, I can take 'conceiving' in two senses and have 'Sin' spring from Satan's head! That'll also be a slap at the Zeus myth on Athena's birth -- goddess of wisdom, hah! The owl of Minerva flies only at dusk because she prefers the gathering darkness! Anyway, Sin will open Hell's gates with her key. But I'll be criticized for having an allegorical figure interact with a 'historical' one. Hmmm . . . ah, no problem -- Sin is just Satan's conception, so she's only in his head, anyway! He's insane and hallucinates the encounter. But I've got to make the episode intriguing. Hmmm . . . ah, I've got it! James 1:15. Satan's lust for power brings forth Sin and Sin brings forth Death! I'll write up a gripping little allegory on this and 'fit audience find, though few' who'll understand that it's all in Satan's mind. I haven't really resolved my dilemma of fallen or unfallen, of course, since the fallen Satan would, implicitly, be the one who opens the gates, but I'll at least have told a good tale to cover the gap."

Or something like that . . .

Such is my take on things -- and explanation for Milton's addition . . . through channeling Milton . . .