I just finished reading C. S. Lewis in A Time of War by Justin Phillips. It seems Lewis went to great lengths to ensure that everything he said in his BBC talks that became Mere Christianity was orthodox for a large cross-section of the Christian faith available in England at the time. He consulted Anglican, Dissenting, and Roman Catholic authorities to verify that he did not say anything that would be seen as incorrect by any of these traditions.

But he did not consult Eastern Orthodox or Reformed theology experts. It also seems to me that by leaving out controversial topics (e.g., papal authority, baptismal practices, etc.) Lewis might also have left out critical beliefs of certain faith traditions—even core beliefs in some cases. (I think leaving out these "internal matters" was the right call at the time, but it might leave us with an incomplete view of Orthodoxy.)

My question is two-fold:

  1. Did Lewis say/write anything in the series that would be rejected by Orthodox or Reformed Christians?
  2. Does Mere Christianity cover enough of the bases for most Christians to be a good reference for what constitutes the core of the faith?
  • Hey Jon thanks for coming by. This is an absolutely awesome question!
    – Caleb
    Commented Jan 6, 2012 at 21:01
  • @Caleb: It occurred to me that I can't very well admonish folks for avoiding BH.SE if I refuse to look at this site. Plus it's a question that won't work in my usual haunts. Commented Jan 6, 2012 at 21:40
  • We certainly struggle here sometimes, people just don't come up with very many quality questions. This sort of thing does much to raise the bar to where it should be. It fits our guidelines exactly without being contrived. I'd like to see some well researched answers on this; if it doesn't get them I may help with a bounty when it's eligible.
    – Caleb
    Commented Jan 6, 2012 at 21:45
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    "Controversial topics" and "critical beliefs of certain faith traditions" are pretty much by definition not core topics. If a belief is held only by a subset of Christianity, no matter how firmly it is believed by that subset, it isn't core. "Mere Chrstianity" was never intended to be "complete". To drop into mathspeak it was intended to describe the intersection, not the union, of the different Christian traditions. Commented Jan 10, 2012 at 18:57
  • I think the NIV is a better core for Christianity belief. Mere Christianity is MERELY a thesis. Commented Dec 23, 2013 at 3:12

3 Answers 3


This is what Lewis has to say for himself in his introduction:

I hope no reader will suppose that "mere" Christianity is here put forward as an alternative to the creeds of the existing communions—as if a man could adopt it in preference to Congregationalism or Greek Orthodoxy or anything else. It is more like a hall out of which doors open into several rooms. If I can bring anyone into that hall I shall have done what I attempted. But it is in the rooms, not in the hall, that there are fires and chairs and meals. The hall is a place to wait in, a place from which to try the various doors, not a place to live in. For that purpose the worst of the rooms (whichever that may be) is, I think, preferable.

Lewis (along with contemporaries such Dorothy L. Sayers and Dietrich Bonhoeffer) played a part in promoting the Ecumenical movement and struggled with the definition of the Church. On the one hand, philosophically there ought to be a unifying system of belief among the body of Christ. On the other, many of us find life in the beliefs and practices that are most divisive. (Depending on which side of the Adriatic Sea you live on, Hesychasm is either "navel-gazing" or experiencing God.)

Mere Christianity proposes a solution that we simply ignore those things we disagree on and talk about those that are common. To use Lewis' analogy of a large building with many rooms, the hallways will have beige carpet and unobjectionable artwork and plants that don't require much in the way of care. In the same way, "mere" Christianity will insist on only those beliefs and practices that remain when the bulk of disagreement is removed.

Shockingly, what's left over turns out to be supremely rich.

After a paragraph in which he explains that some people may spend considerable time in the hallway before finding (what we Protestants sometimes call) a "church home", Lewis address picking a denomination and how we should think of those we disagree with:

In plain language, the question should never be: "Do I like that kind of service?" but "Are these doctrines true: Is holiness here? Does my conscience move me towards this? Is my reluctance to knock at this door due to my pride, or my mere taste, or my personal dislike of this particular door-keeper?"

When you have reached your own room, be kind to those who have chosen different doors and to those who are still in the hall. If they are wrong they need your prayers all the more; and if they are your enemies, then you are under orders to pray for them. That is one of the rules common to the whole house.


More than anything else, Mere Christianity stands as a valiant attempt at ecumenicism. If it fails, it fails because the idea of bringing the entire Christian faith into one house is unworkable. I would prefer to believe that it succeeds.

  • I'm still struggling with an answer. This is my (current) best shot. Commented Jan 11, 2012 at 1:36
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    Ecumenism is a movement which tries to make all Christians agree on everything. Mere Christianity is an attempt to define a core a Christian belief, which is very different. Commented Jan 11, 2012 at 18:37
  • Have you had any further insight since this was posted? Commented Dec 16, 2015 at 16:09

The Reformed perspective

Tim Challies (a well known reformed pastor in Toronto) gives an in depth opinion on Mere Christianity on his blog.

Reading Classics - Mere Christianity by Tim Challies part I, II, III, IV, V, VI, VII

From the reformed view, Lewis does make the common errors with regard to free will and God's sovereignty, especially with regard to the Garden of Eden.

He also errs in some ways that that are problems with other denominations outside of the Reformation movement, including some "Open Theism", his opinion on Evolution, and his version of salvation where people from other religions may be saved without ever becoming Christians.

Tim Challies' posts with the harshest critiques are (III) for free will and the Garden of Eden, (VI) for Open Theism, and (VII) for evolution.

In general, he still regards the book as a classic and worth reading with a ton of great quotes.

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    "errs in some ways that all evangelical Christians would probably agree with". Is that the same as "says something that the writer personally disagrees with"? Commented Jan 10, 2012 at 21:22
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    John Piper makes a similar case using the entire Lewisian corpus. I'm deeply in conflict over the theological disagreements between these two men, but I'm so glad Piper has such a respect for Lewis. Commented Jan 11, 2012 at 1:48
  • @DJClayworth - I am reformed and agree with all of Tim Challies points. I was trying to say that these are generally agreed upon heresies for non-reformed congregations, or at least that they don't have much to do with reformed theology. The exception might be Evolution, which has some support in people that I wouldn't have expected, but I don't know the details. I'm open to disagreement though. Commented Jan 11, 2012 at 18:21
  • @DJClayworth - I looked up Open Theism and found that no denominations formally believe in it. It is primarily held by professors, though some denominations have come close to allowing it after being challenged by some of the professors. Commented Jan 11, 2012 at 22:35
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    Lewis' views on evolution (at the time of Mere Christianity) are summed up here "I am not either attacking or defending Evolution. I believe that Christianity can still be believed, even if Evolution is true.". That is certainly the mainstream Christian view, and one probably held by most Reformed Christians. Commented Jan 12, 2012 at 17:02

The same could be said of G.K. Chesterton and probably a whole host of smart writers wholly ignorant of large swaths of Christianity. One difference, pointed out here is that Lewis doesn't see a need for a Church and without a Church it is hard to have a priesthood and without a priesthood it is hard to have a sacrifice - so I'd imagine that's contrary to Eastern Orthodox (insofar as it is contrary to regular orthodoxy as practiced by both lungs of the Church).

(I wasn't intending on answering this since, I'm not an expert of mere Christianity, I think I read it all but can't remember - except the part where he said he's not going to talk about Marian Dogma)

  • When I have access to my copy of Mere Christianity, I'll check what Lewis has to say on the Church. Perhaps he didn't touch on the subject of what the Church consists of as he didn't wish to stir up that particular controversy? Bonhoeffer struggled mightily with the definition of "Church" as well during that era. Can we really say that Chesterton (or Lewis) were "wholly ignorant" of the Eastern Orthodox church? That seems a bit unfair to them. Commented Jan 6, 2012 at 23:11
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    I finally got around to cracking the books and in the introduction (where he mentions Mariam Dogma) Lewis considers "mere" Christianity to be barren, like a hallway and the rooms are where people actually live. The rooms are specific denominations. And he does mention that Greek Orthodoxy is one of the rooms. He also says in chapter 11 of book 3: "Daily prayers and religious reading and church going are necessary parts of the Christian life." So I think your source is mistaken. Commented Jan 9, 2012 at 4:28
  • Unless the priesthood is Christ's and fulfilled by Christ (Heb 2:17,18; 4:14-5:10; 7:1-8:7; 10:19-22) and the sacrifice was already offered once for all, rather than repeatedly (Heb 9:24-28; 7:27; 10:1-14; 13:15). I realize this flies in the face of some denominations (unless I am mistaken, the Orthodox wing of the church does not teach an ongoing sacrifice as the Romans do), but I felt a biblical response to these two points was warranted.
    – Don Jewett
    Commented May 1, 2014 at 4:39
  • @DonJewett distinguo, the Catholic Church teaches that there is One Sacrifice, made present at each Mass.
    – Peter Turner
    Commented May 1, 2014 at 16:28
  • Point taken, although that is within the meaning of "ongoing sacrifice." My point is that there is no necessity of a priesthood in order to offer a sacrifice if the sacrifice has been fully offered once-for-all by the Great High Priest. I am responding to your phrase, "without a Church it is hard to have a priesthood and without a priesthood it is hard to have a sacrifice." I heartily disagree. Rather, "without Christ there is no priesthood and without Christ there is no sacrifice." Fortunately, Christ is fully present in his body, the universal Church, through the indwelling Holy Spirit.
    – Don Jewett
    Commented May 1, 2014 at 21:54

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