|Satan in Eden (1866), by Gustave Doré|
Thesis: In Paradise Lost, although Milton draws upon strong religious and archetypal currents in crafting his Satan figure around the image of the Biblical adversary, Satan's condition should be interpreted rather as a depraved state of mankind comparable to (though by no means equivalent to) that of Adam and Eve following their fall from Eden. The archfiend's condition, then, becomes a lens for understanding the human emotions of pride, grief/loss, and doubt.
Commence Thought Vomit
The Fall should be understood not as an individual choice nor a bipartite decision but rather as the combined efforts of Adam, Eve, and Satan, each in a position of inferiority to God--> semi-Marxist.
Satan is exceptionally ponderous, questioning his own ability and reflecting often on why he has been destined to such a fate.
Satan's flaws lend humanity, complexity, and dynamicity, whereas the perfect characters of God and the angels (with the exception of perhaps Abdiel, who's a boss) appear to be more static and flat.
If Satan is really man, in his lowest form, then sin and death are his children: mankind crafts his own sorrows. Eventually, even Satan comes to believe his own lies, and they become a eternal prison for him. Ultimately, the difference between him and Adam and Eve is that he sought his own will when his sin was discovered, while Adam and Eve accepted correction.
Difficult NOT to sympathize with Satan because of his humanity. We all see a bit of ourselves in him. Even Milton writes himself into the Satan figure to some extent, self consciously repeating arguments from Tetrachordon and likewise citing his ambitions to "soar above th' Aonian mount" as parallel to those of Satan in desiring to ascend above the heavens and take God's throne.
Satan eventually weened out of the story as a whole. As he becomes less prevalent, the redeemed man (i.e. Adam and Eve, seeking redemption) becomes more prominent. The epic then becomes a progression from depravity to redemption (or at least the path leading up to it). This is likewise coupled with the physical diminution of Satan as an entity: huge to cherub to cormorant to toad to snake.
Wilderness vs. Chaos
Fish argues that PL is about a reader experience rather than a narrative, but I would extend that to assert that the reader in some sense becomes Satan in seeking to understand him. All other major figures within the narrative structure pretty much have their roles and characters set. Satan's character, however, is unbounded enough that Milton can explore emotion and thought in ways that are not possible for other characters. He is, in some sense, the only "free" character, so he gets most of the character development (which we in turn associate with humanity).
"Which way I fly is hell; myself am hell."
Actions presage certain Biblical passages - climbing over the wall (John 10:1), mountains fall on me and cover me (shame, Isaiah 2:10, Hosea 10:8, Luke 23:30, Rev 6:16), etc,
Satan as a construct of the vices of man rather than vice versa (pun intended). Each vice is manifested both in Satan and in Eve, who in effect becomes the representation of humanity as a whole. Satan wants to be higher than God; Eve wants to be higher than Adam. Eve wants to be alone; Satan ventures off alone into chaos and 'falls' again in becoming confined to a serpent's body (mortal). Two books just Satan at beginning; two books just Adam and Eve at end.
Eve and Satan - persuasion, desire to be alone
Struck "stupidly good" at the sight of Eve. Good inside of Satan. He's not evil incarnate (or precarnate) but rather has good inside that is stunned into expression at times.
Snake 'eats' fruit, Eve eats fruit. Becomes sort of an adoptive process wherein Satan seeks to adopt Eve (and mankind) into his own misery.
The more I think about it, the more I think I'd like to use Eve as the representation of mankind and Satan as a reflection of the fallen nature of mankind. Eve's role as the "mother of all living" lends to such an interpretation, and she becomes the symbolic representation of mankind as a body. Her submissive position toward Adam (who in some sense can be seen as a sort of God figure in granting free will to Eve and in his at times insufferable goodness) mimics the relationship of the church (humanity) to the bridegroom (Christ). Feminist questions aside, that means that Eve and Satan are in some sense parallel figures, the one exacerbating his own state and the other choosing redemption in sacrificing her will to God (technically to Adam, but that's only if he is governed by God's will). Such an understanding of Satan as a reflection of the fallen nature of mankind lends itself not only to a more morally instructive/enlightening mode of reading but likewise opens the way for further analysis of the work on the grounds of Marxist, psychoanalytic, biographical, and feminist claims.