I've been an avid reader of C. S. Lewis' non-fiction since my high school days; and although I didn't discover G. K. Chesterton until after seminary, I've consumed thousands of pages of his writings in the years since. (And still have thousands left to go: Chesterton was astonishingly prolific.) My faith has been profoundly influenced by both thinkers, and I've read and reread their major works many times. Although they have very different writing styles, didn't know each other personally, and belonged to different theological traditions (Lewis was an Anglican, Chesterton a Roman Catholic), I tend to think of them together, and they were in fact similar in many ways. Lewis was influenced to a great degree by Chesterton, their most influential works were written for a "popular" rather than an academic audience, and both of them produced a wide range of writings, including philosophy, history, literary criticism, apologetics, and fantasy.
Periodically, I've run into the claim that Lewis and Chesterton are "folk theologians", with the implication that they're not writers "real theologians" need to study. This has always bothered me, especially when I see them simply ignored. Hendrikus Berkhof's Two Hundred Years of Theology has not one reference to either Lewis or Chesterton. In The Story of Christian Theology, Stanley Grenz and Roger Olson spend some four hundred pages on 20th century theology, again, without a single reference. To pick a more specialized example, Miroslav Volf's Work in the Spirit quotes from some 276 authors (by my count) in his theological critique of the debate between Adam Smith and Karl Marx, without once mentioning Chesterton's innovative (and deeply Christian) "distributivist" alternative. Of course, a cottage industry has recently grown up around Lewis and Chesterton, with new books on Lewis especially being introduced on a regular basis. But these studies are somewhat specialized and, in my limited experience, continue to be ignored by the mainstream of academic theology.
I think there are several reasons why Lewis and Chesterton are so often ignored by professional theologians.
The first reason is that neither made the sort of substantial and substantially new contributions to the Church's self-understanding that are a part of the heritage of, say, Augustine, Aquinas or Luther. No church body has ever modified their creed because of Chesterton's careful analysis of the doctrine of the Trinity. Nobody ever founded a new denomination because of Lewis' shattering insights into divine grace. That said, neither Moltmann nor Pannenberg (to pick two influential 20th century academic theologians) could pass the "have you started a new denomination or launched a new creed" test either. And I certainly wouldn't claim that Lewis and Chesterton are at the level of Augustine or Luther: I think they're important, but they're not that important.
A second and perhaps more germane reason is that most of Chesterton and Lewis' original contributions are outside the traditional loci of theology: what they have to say doesn't fit well into a textbook on systematic theology. Although Chesterton and Lewis do touch on traditional theological topics, such as the doctrine of the Trinity or ecclesiology, when they do so, they make it clear that they are representing and defending the tradition, and not so much trying to contribute to it. Even so, I do believe that they make substantial contributions to Christian thought, broadly understood. I don't have time to go into a detailed defense of this position right here, but suffice to say that Chesterton's "military loyalty to the world" and Lewis' insistence that "to see through everything is the same as not to see" are largely original, compelling and deeply Christian.
A third reason I've heard to explain this neglect is that neither Lewis nor Chesterton interacts extensively with other theologians: they don't contribute to the conversation. This is partly true, if you limit yourself to purely academic theologians. But it's simply not true that Lewis and Chesterton don't interact extensively with a wide and impressive array of thinkers. Their books can easily be read as an extended dialogue with the whole of the Western philosophical, theological and literary tradition. Chesterton's work on Aquinas ("The Dumb Ox") and St. Francis are true classics, not to mention his literary biographies of Chaucer, Blake, Dickens and others, or his treatment of world history in The Everlasting Man. Lewis' explanation of the Trinity in Mere Christianity owes a great deal to Athanasius' On the Incarnation. The Pilgrim's Regress is an entertaining and enlightening Christian critique of late 19th and early 20th century British and continental philosophy. Anything more than a casual reading of either author will show that they are in conversation with hundreds of philosophers, theologians, historians, poets and novelists, and that their contribution to these conversations is extensive and substantial. Of course, these contributions are not always specifically theological, but if the old view of theology as the queen of the sciences has any validity whatsoever, that should hardly be held against them.
A fourth reason reveals a bit more cynicism on my part; take it for what it's worth. Lewis and Chesterton don't talk the language of modern, professional, academic theologians. You know the language I'm talking about:
"Toulmin is not guilty, as Scheibe is, of failing to recognize the possibility that a new theory in science may not be reconcilable with its predecessor in such a way that the latter is included in or interpreted by the former."
"Bonhoeffer's customary second thesis, Act and Being (1931/1962), took issue with current idealist philosophy, arguing that neither in its neo-Kantian or its neo-Hegelian forms could philosophy come to terms in the notion of a God truly transcendent; such a conception must wait upon theology, upon revelation."
Nor do their writings have the studied ambiguity of the other dominant linguistic paradigm available to philosophers and theologians, that of being pithy, epigrammatic, and not-quite-comprehensible. You can see this in Kierkegaard:
"The first question in the earliest and most compendious instruction the child receives is, as everyone knows, this: What will the child have? The answer is: da-da. And with such reflections life begins, and yet men deny original sin. And to whom does the child owe its first drubbings, whom other than the parents?" (Either/Or, p. 1)
"Naming appears as a queer connexion of a word with an object. – And you really get such a queer connexion when the philosopher tries to bring out the relation between name and thing by staring at an object in front of him and repeating a name or even the word 'this' innumerable times. For philosophical problems arise when language goes on holiday." (Philosophical Investigations, par. 38)
Both Lewis, an Oxford don and Cambridge professor, and Chesterton, an accomplished literary critic, clearly knew how to talk the language of academia. But in nearly all of their writings, even in their more technical book-length treatments on academic topics, they decline to do so. Lewis gives his own reasons in the brief essay, "Before We Can Communicate":
"[If you try to speak in plain language, you will discover] just how much you yourself have, up to that moment, been understanding the language which you are now trying to translate. Again and again I have been most usefully humiliated in this way. One holds, or thinks one holds, a particular view, say, of the Atonement or Orders or Inspiration. And you can go on for years discussing and defending it to others of your own sort. New refinements can be introduced to meet its critics; brilliant metaphors can seem to illuminate its obscurities; comparisons with other views, 'placings' of it, are somehow felt to establish its position in a sort of aristocracy of ideas. For the others are all talking the same language and all move in the same world of discourse. All seems well. Then turn and try to expound this same view to an intelligent mechanic or a sincerely inquisitive, but superficially quite irreverent, schoolboy. Some question of shattering crudity (it would never be asked in learned circles) will be shot at you. You are like a skilled swordsman transfixed by an opponent who wins just because he knows none of the first principles. The crude question turns out to be fatal. You have never, it now appears, really understood what you have so long maintained. You haven't really thought it out; not to the end; not to 'the absolute ruddy end'.
"You must either give it up, or else begin it all over again. If, given patience and ordinary skill, you cannot explain a thing to any sensible person whatever (provided he will listen), then you don't really understand it yourself."
This is one of the many reasons why Chesterton and Lewis have been so popular: precisely because they write so well, they don't sound like academics. You have to pay close attention to realize the extent of the learning which sits behind nearly every paragraph.
But precisely this clarity, I believe, works against them in the academic world. For one thing, it's admittedly not very precise: it leaves you to fill in many of the gaps yourself, and you have to go hunting around in Augustine or Athanasius or even Freud to find a passage Lewis refers to obliquely (perhaps even leaving out the name of the theologian with whom he is discoursing). But another is that, to an academic, it just doesn't sound right. This may be hard for non-academics to believe, but I'm convinced that academics like the sound of academic writing. It gives them a sense of security, confidence, even superiority. It's very similar, I believe, to why I carried around a brief case when I was in high school: I thought it made me look intelligent and serious.
How else could you explain the production of so much writing that sounds like this?
"More specifically, Winch seeks to deal with the problem of the universal and the particular in regard to the study of alien societies in a manner that is quite different from one of the traditional ways in which this has been approached. A pervasive framework for dealing with the universal and the particular has been to think we must first specify what is universal or generic (for example, the supposedly universal 'categories' of rationality) and then treat the specific differentia that distinguish particular societies."
(And that's from a book I liked.)
To summarize, there are a variety of reasons why Lewis and Chesterton are ignored by mainstream academic theology, and some of them are legitimate. But I don't think they're ultimately persuasive; and I believe that they're outweighed by the numerous benefits which would accrue to theologians who spent more time reading Lewis and Chesterton. More on that tomorrow.