I think I understand why so many people have difficulty simply saying “Aslan IS Jesus, period.”
Persons hostile to Christianity have a plain, up-front reason for wanting to change Aslan’s identity: they don’t want to owe anything to the orthodox Biblical Jesus, and they want to hijack Aslan (or perhaps, in their minds, liberate Him), making Him a small-g pagan god in an ultimately humanistic fantasy. (As I wrote elsewhere, it’s actually understandable why some want Aslan to be less than omnipotent, precisely so that He can be seen as MORE heroic when opposing evil that MIGHT be able to defeat Him.) But the case of Christians disliking the idea is more subtle. Every Christian (except for those pharisaic types who call all fantasies uniformly demonic) is willing to recognize Aslan at least as embodying the personality traits of Jesus; but in spite of such powerful narrative clues as Aslan taking the form of a LAMB in addition to that of a lion, many balk at agreeing that Mr. Lewis meant Aslan unequivocally to BE Jesus, none other than the same Jesus Who is found in the New Testament.
I believe I have grasped the cause. These Christians resist calling Aslan Jesus for the same reason as even well-intentioned people at the fringes of Christendom resist calling Jesus God.
If you don’t understand the Trinity, the claim of Jesus to be God can sound like blasphemy–the presumptious attempt of a man, who started out as a man, to elevate himself to Godhood. This, in fact, was the very charge brought by Our Lord’s enemies. But when you do understand the Trinity, you realize that Jesus didn’t CLIMB UP to “become” God; he already WAS one of the three co-existing aspects of God, and He CAME DOWN to become human.
If you don’t understand the conscious intent that Mr. Lewis formed after God’s mental suggestion to him for the character of Aslan took hold, the claim that Aslan is Jesus can sound like blasphemy–the attempt of an author to take a character he happened to enjoy inventing, and endow this character with the dignity of the Savior. This, in fact, is exactly what the malicious Philip Pullman has accused Mr. Lewis of doing with Aslan. But when you do understand the intent of Mr. Lewis, you realize that Mr. Lewis wasn’t indulging in turning a talking lion into a Christ-figure at the expense of Biblical doctrine; instead, he was imagining what form THE ACTUAL CHRIST might assume if ENTERING such a mythic world as the Narnian world.
Mr. Lewis asserted in his essays that there is not, and cannot ever be, ANY being ANYWHERE, other than God, who is eternal from eternity-past, uncreated, omnipotent and absolutely self-sufficient. Therefore, when Aslan is described in “The Magician’s Nephew” displaying the attributes of Almighty God, creating something out of nothing, and on top of that being seen doing the creating by persons from the real world, Mr. Lewis CANNOT be inviting the reader to conclude, “Okay, there IS someone omnipotent besides God after all.” Mr. Lewis took God’s exclusive Godhood too seriously to blur it.
Jesus being God does not wrongly exalt mankind to Godhood, because Jesus WAS God first. Aslan being Jesus does not wrongly exalt fantasy characters, because the whole point about Aslan is Jesus Himself ENTERING a world purposely modelled upon myths and fairytales.
Ut fidem praestem in difficultate!