There’s a strand running through Lewis which observers and critics put down to his Christianity but which can be seen in other terms, at least initially.
It is to do with the Big Question, or the idea that everything, all our daily lives, every other concern that we have as human beings, rests on one fundamental factor: whether or not the universe is empty, or full of meaning. It’s this which powers all Lewis’s fiction, and much of his non-fiction too. The concept that the universe is empty leads to an Ironic universe in which what seem to be patterns or sequences turn out to be tricks, illusions or randomly generated events; the concept that the universe is full of meaning leads to an Epic universe in which order is the default position and in which a divine joy overwhelms any mortal perspective.
If one believes in an ordered universe, then ’We are not necessarily doubting that God will do the best for us; we are wondering how painful the best will turn out to be' as Lewis puts it. The pain and suffering which we encounter have to be seen as part of the fabric of what will ultimately turn out to be a good universe, good beyond our imaginations.
There are no half-measures in such a universe. As Lewis famously put it, 'I am trying here to prevent anyone saying the really foolish thing that people often say about Him: I’m ready to accept Jesus as a great moral teacher, but I don’t accept his claim to be God. That is the one thing we must not say.' (Mere Christianity). Lewis continually leapt towards the Absolute of a filled universe: 'Has this world been so kind to you that you should leave with regret? There are better things ahead than any we leave behind’ he wrote in Letters to An American Lady.
Lewis is thus able to turn our normal human expectations on their head: 'It would seem that Our Lord finds our desires not too strong, but too weak,’ he writes in The Weight of Glory, and Other Addresses. ‘We are half-hearted creatures, fooling about with drink and sex and ambition when infinite joy is offered us, like an ignorant child who wants to go on making mud pies in a slum because he cannot imagine what is meant by the offer of a holiday at the sea. We are far too easily pleased.'
This perspective enabled him to give concrete advice about how we should live from day to day, subject as we are to the vagaries of human emotion and the transient world in which we currently live which frequently gives us the impression that there is only emptiness behind it: 'The great thing to remember is that though our feelings come and go God’s love for us does not’ he writes at one point, and 'Remember He is the artist and you are only the picture. You can’t see it. So quietly submit to be painted—i.e., keep fulfilling all the obvious duties of your station (you really know quite well enough what they are!), asking forgiveness for each failure and then leaving it alone.You are in the right way. Walk—don’t keep on looking at it.' as he says in The Collected Letters of C. S. Lewis, Volume lll: Narnia, Cambridge, and Joy 1950-1963.
The power of the Narnia books does not rest in the creation of a world on the other side of a wardrobe, charming though that might be; nor does it depend on the allegorical elements of ‘Aslan as Christ’, though of course they play a part. Narnia resonates with attractive energies simply because it is founded upon the biggest vacuum of all, the question of the primary nature of the universe. We read the stories and are fascinated by them as we might be captivated by the dancing of light on the surface of a lake, but the deeper currents of that water are to do with the world in which we live and its character, and that’s what really holds our attention.
As Lewis says in The Great Divorce, ’There is but one good; that is God. Everything else is good when it looks to Him and bad when it turns from Him.'