C S Lewis: The author examined

Take one Christian apologist. Add a trip to the zoo. Result: one of the 20th century's most resonant myths for children. As the new Disney version of 'The Lion, the Witch and the Wardrobe' opens, Murrough O'Brien examines the complicated character of C S Lewis

Two pages into C S Lewis's essay, "The Weight of Glory", a sudden shift of tone occurs. Lewis addresses the reader directly: "I am almost committing an indecency. I am trying to rip open the inconsolable secret in each one of you - the secret which hurts so much that you take your revenge on it by calling it names like Nostalgia and Romanticism and Adolescence... the secret we cannot hide and cannot tell though we desire to do both. We cannot tell it because it is a desire for something which has never actually appeared in our experience."

He was speaking of something he elsewhere called Sehnsucht, a sense of... well, how do you put it? It's sometimes conveyed through music, or a landscape, or a book, or a person, and it both consoles and tantalises. Is it God, or gods, or nature, or wonder, or awe, or love? Enough to say that it leaves you aching with longing for something you know but can't place. Should you go back to that tune, or landscape, or person, or book, you will find only a memory - for these things were Accidents, as Catholics would say, or Portals, as mystics might say. Now call to mind Aslan's cry to his new-born world in Lewis's novel, The Magician's Nephew (1955): "Narnia, Narnia, Narnia! Awake. Love, think, speak." Lewis knew that there was no golden city, so he wanted to create one; the Arthurian age never existed, so it must be conjured up.

He was always deeply dislocated. He decided, as a child, that he was to be called "Jack", not Clive. An almost pure Celt (part Welsh, part Irish), he never identified with Celticity. His prep-school days were hideous, lived under the rule of a proven psychopath, the headmaster Robert Capron, who died in an asylum in 1911. His mother died of cancer. He fought at the Somme, and took on the mother of a friend who had died in the Great War. But then, he took on everyone, whether as strays, friends or enemies. He abandoned atheism as an adult with far more reluctance than he had abandoned faith as a child. C S Lewis became perhaps the most learned and compassionate Christian apologist of the last century, but it was characteristic of him that the clinching moment should have come on a visit to the zoo.

He was his own man, and made his own decisions. But how very much it cost him. The love denied him in his twenties, but granted him in his sixties, was snatched away when the loving, insufferable Joy Davidman died of cancer. His Irish nurse schooled him in folklore, he schooled himself and others in storytelling. Norse sagas, the chivalric literature of the 14th century, The Faerie Queene, the spiritual fantasies of George Macdonald, were all fed into that curiously quiet and analytical mind, before falling on to the coals of his imagination.

Where does the uniqueness of Narnia lie? Not in the fact that there, children are forced to adopt adult responsibilities - that happens in any decent book for children. Its mythology is of course extraordinarily ecumenical. We have fauns from Ancient Rome, dryads and centaurs from Greece, dwarfs and werewolves from Northern Europe, efreets from Arabia, woses from Anglo-Saxon England, talking animals from everywhere. Yet you can't see the stitches; in Narnia these creatures co-exist in an ideal model of folkloric multiculturalism. But if Lewis was the first in modern times to attempt such a synthesis, it is not that alone which commands our attention. Rather, he gives us, with wonderful lightness, the child's eye. Unlike some other writers for children - Lewis Carroll, say, or Alan Garner - C S Lewis never falls into the error of thinking that children simply take the magical in their stride.

In Narnia, we see Lewis himself, "beery, breezy", kind and stern; always knowing a little bit more about what's going on from the outside, always humble in acknowledging what he can't know from the inside. He wrote an essay called "The Poison of Subjectivism" about those who presume to analyse human experience from without. This is what marks the difference between the attacks on Tolkien and the attacks on Lewis. Tolkien is barely present in his works. Lewis is omnipresent in Narnia. You can't attack Narnia without attacking Lewis.

He can be funny, rather than "humorous" (as Tolkien only just managed). Wit and pathos, grandeur and bathos, are mingled even in The Last Battle (1956), the culmination of the Narnia chronicles. He shifts idiom swiftly and easily. In moments of stress, kings address queens with childish familiarity; a mouse spouting chivalric platitudes is answered with a groan of cockney impatience from a ship's bo'sun; the stately style of Calormen, the sinister empire to the south of Narnia, is as much respected as mocked.

Each book has a very different quest. The Lion, the Witch and the Wardrobe (1950) is a book for children, or, rather, a book for a particular child - Lucy Barfield, Lewis's goddaughter. The delights are the delights of childhood. There is a ruthless economy of style, so ruthless that when you read the book as an adult, you're likely to find the things that moved you as a child shown in a manner almost brusque. The sacrifice of Aslan moves us not because we love him (we haven't got to know him well enough at this stage), but because Susan and Lucy do. The Horse and His Boy (1954) is another kind of book altogether: intricately characterised, funny, with significantly lower stakes. But now we have the first glimmers of adult moral choice. Shasta, a prince brought up by Calormene fishermen, untrained and mortally scared at the battle at the gates of Anvard, reflects, "If I funk this battle, I'll funk every battle..." This echoes something we see in The Great Divorce (1945), Lewis's fantasy of a visit to heaven from hell, when a saved spirit says to a murky ghost who wants a few days' reprieve, "This moment contains all moments."

Prince Caspian (1951) shows us Lewis's deep, and too-little reported, loathing of oppression. Lewis had a horror of imperialism in any form: he went so far as to suggest that we live so far from other worlds because God wanted to put us under quarantine, to protect nobler, or more innocent, races from our savagery.

In The Voyage of the Dawntreader (1952), Lewis gives us an Immram, an Irish sea-quest (the debt to The Odyssey has been exaggerated). Here, Lewis shows us the horror of following the wrong kind of dream. The Silver Chair (1953) has Eustace and Jill going in search of the missing Prince Rilian. The witch who rules the underworld denies that there is any sun up above, and the bewitched Prince Rilian, until the children release him from the Silver Chair, sees no harm in laying waste the land he is supposedly to govern. Lewis believed in the right to rule, but never in the right of conquest.

The Last Battle propels the reader to a choice, just as it does its characters. You can find Narnia's apocalypse simply depressing (the adolescent phase), glorious but miserable (if you're a child), wonderful and affirming (if you're an adult). Narnia is lost, betrayed by Shift, the shiftless ape, but that does not, as Lewis put it, "alter the allegiance of any free man". Tirian and the horses go down with Aslan, in a cause they believe to be lost, and are rewarded.

Did Lewis "libel life", in the words of Philip Pullman? No, but it could be argued that he libelled love. There was, until too late in his life, no place for the state of being "in love". In a manner depressingly redolent of modern moralists, he preferred to see it as a hormonal storm rather than a mystic portal to the beloved's true nature such as we see in Dante or Petrarch. He could appreciate it in theory, in the novels of his friend Charles Williams, or in the works of Plato, but not praise it with any conviction. The reason is not far to seek: before Joy Davidman came all he knew of love was painful duty or unappeasable loss.

But his stories did not merely give back forgotten ideals to people who would not have received them in any other form; they forced Lewis himself to purify his understanding of those ideals. He often returned to the idea that putting complex thoughts in plain words acted as a test of those thoughts. As he put it: "Any fool can write learnedly." We see something comparable at work in the Narnia Chronicles. None of his more questionable positions - that the materialist position is self-contradictory; that consciousness of sin, as opposed to mere awareness of wrongdoing, is perennial and universal; the oddly incoherent apologia for not being a pacifist - get an airing.

Most of his best thoughts do, sublimely. In Eustace's transformation from dragon and back again, we see the unpeeling of the self from its casque of self-justification and cant which we cannot achieve by ourselves. The Green Witch, the White Witch and the Calormenes all, at some point, evince the power of evil to conquer our better natures by caressing us. The idea of evil as blindness is personified by those dwarves in The Last Battle who cannot taste the glorious dishes set before them, who cannot see or smell Aslan, trapped in their world of grievance, even in Heaven. The recognition that if you put a secondary good above the highest good you will lose both is felt by Digory Kirke as he is forced, in The Magician's Nephew (1955), to choose between his mother's life and the life of Narnia. He chooses the latter and earns the former. Above all, Lewis's uncompromising assertion that it is moral choice, rather than trauma or time, which forms character, underlines the whole vision. These stories rescued Lewis from his besetting sin as a thinker; that of assuming, in all innocence, that others thought like him, and if they didn't, that they ought to.

Both Lewis and Tolkien believed that literature had hit critical mass in their day, and that the only way forward was to go back, to rediscover the joys and terrors of an older, wilder world. It is significant that the White Witch's only contribution to Narnia should be something urban: a lamp-post. Tolkien blew the dark war-horn of ancient wisdom, Lewis the clear trumpet of the chivalric ideal. What music they could have made had Lewis not committed the unpardonable error (in Tolkien's eyes) of mingling worlds.

Who is Lewis himself in the Chronicles? He is Edmund, of course, and also Eustace. He is the betrayer and the know-all, the traitor and the prig. The most generous, loving, funny and courageous of men could never forget that he had in his early life accepted what he called in The Great Divorce "invited confusions", mislaying his faith and misusing his love of knowledge. Edmund is a mocker, as Lewis once was. But the stone lion Edmund scrawls graffiti on still looks "so terrible, and sad, and noble". In The Great Divorce, the ghosts brought up from Hell to visit Heaven (they can stay there if they choose), are always running away from the primary spiritual duty, to confess.

This brings us to the first problem the adult fan feels on re-reading Narnia: childish fears can be terrible of course, but childish problems are rarely so terrible as adult ones. A child who behaves badly and then sulks (from a bad conscience) is likely to be forgiven. An adult has no such guarantee. Lewis was right not to patronise children, wrong to suggest that adult experience is merely a more elaborate version of a child's.

It is true that Lewis had little sympathy for Islam (and he was spectacularly obtuse in his understanding of it). But the North, and its legends, chanced on his consciousness first. Like Tolkien, he believed in the Old English principle of aeregood, that what comes first has, at the very least, a primacy of excellence. The North was the portal for his Sehnsucht.

His world is notoriously hierarchical, but there is a reason for this. One who creates has the right to control, one who conquers does not. But here's the paradox: Aslan, the world-creator, does not seek control - rather, like the true lover, he wants his beloved to be all she could be. Lewis was not "tolerant", as his opponents have correctly observed. But Love, for him, does not "tolerate": it excuses errors, and forgives wrongs, and always seeks the good of the beloved.

C S Lewis created two timeless characters. One is already well-known, and, with the forthcoming film, will be better known still. The other is the titular devil in The Screwtape Letters (1942), a record of Lewis's own spiritual doubts. But, paradoxically, it is Screwtape who puts Aslan's case better than Aslan himself. When Screwtape's nephew, Wormwood, loses his "patient" to Heaven, Screwtape anticipates the patient's reaction to the heavenly powers who were with him all through his trials: "not, 'Who are you?' but 'So it was you all the time.' "