If not for the fact that this is a satire in earnest, it would serve as a powerful absurdist invective against humanity itself. If this book improved my view of Christians it was only because it points out that all the faults conspicuous in the rabidly faithful are equally well-represented in the uninformed agnostic, if less readily apparent--Lewis does his best to drag everyone down to a common level.
The sharp weapon of Lewis's rhetoric tears down humanity through all its self-righteous hubris, denial, misdirected hopes, and easy mistakes. However, one begins to develop the impression, slowly at first, that Lewis has nothing to offer in return. There are scarcely words of alternatives, let alone improvements.
Lewis does give us a house which disgusts the devils and redeems the sinful, but this perfect representation of Christian values is just a lack of badness, not a profusion of goodness. It is 'suffused' by some sort of magical glow which infects the cat, but magical glows do not a life philosophy make. I got the impression that Lewis hoped to fill in with the good parts later, but couldn't think of any.
Human beings have a cognitive bias for avoiding punishment, even to the point where we will avoid a small punishment rather than seek a great reward. Perhaps this fear consumed Lewis, as it does so many people. That would explain why his books seem more concerned with avoiding small errors instead of seeking out grand achievements.
But then, Lewis has a similar failing with grand villainy. Sure, he's able to point out all the little, foolish errors we make, but he seems to have no ability to understand actual malice or hatred. His demons, like all his villains, just do bad things because it's required of them. Lewis is unable to develop any motivation for them to do evil, which means that, in the end, his vision of evil is silly, petty, and dismissive. He cannot give us a vision of a truly dangerous devil, like Milton's
, just an arbitrary (and easily blamed) antagonist.
Lewis said writing these letters was more unpleasant than any of his other books, and that he could not bring himself to write a sequel. I find little surprise in this, because one can see how, as the book goes on, Lewis more and more recognizes the failures of mankind but when he tries to express what makes him or his faith any different, cannot find anything to say.
The 'suffusing glow' becomes a metaphor for Lewis's own righteousness, but whenever Lewis isn't basking in his own self-righteousness, he is ridiculing someone else's. Lewis' rhetoric is most deficient when he scorns one of man's many faults, then calls it a virtue in the next chapter.
For example, the book begins with the demon advising that humans should be encouraged to think of things as being 'real' without ever questioning what that means. The term 'real life' is meant to act as a self-justification for assumptions, not as an introspective view. This is 'bad' because 'real' has no meaning beyond the opinion of the user, and hence it can be used to justify anything.
Then Lewis begins to talk about how the Christians should make sure to follow what is 'natural', but fails to define what 'natural' is supposed to mean. Like 'real', 'natural' can be used to justify any idea or position, but Lewis does not turn a skeptical eye on himself.
This can hardly surprise, as Lewis maintains a philosophy of Duality. Dualism presents the 'with us/against us' ideal by which any two groups may grow to hate one another despite the fact that they have relatively few differences. As long as one defines the other as bad, there is no need to define the self as good, as in the Dualistic system, there is only good and evil, and you are either one or the other.
Lewis often falls back on this defense, showing how some men are bad, how he is different from them, and then assuming 'different' equals 'better'. He uses rational, skeptical argument to show how flawed his opponent is, but tearing down others is not the same as raising yourself up.
That being said, it would still be refreshing to meet a believer who had put as much thought and work into attempting to understand and explain themselves. It is rare to find thoughtfulness and skepticism, believer or no. Atheists and scientists can be just as troubled, flawed, and deluded as anyone else.
The lesson I will pull from this is that it is important for me to concentrate on myself and my own growth, because worrying about everyone else didn't help Lewis, and it isn't going to help me, either. I must not simply tear down those who are different from me, since this doesn't prove that I am right, any more than a bully proves his superiority by his insults and threats.