Mere Christianity – Book I (Summary)


Book 1
You can look at my more detailed notes, but this is an overview of the content of Book I of “Mere Christianity”…



Mere Christianity

…I have thought that the best…service I could do for my unbelieving neighbours was to explain and defend the belief that has been common to nearly all Christians at all times…So far as I can judge…the book…did at least succeed in presenting an agreed, or common, or central, or ‘mere’ Christianity…it may possibly be of some help in silencing the view that, if we omit the disputed points, we shall have left only a vague and bloodless [Highest Common Factor]. The H.C.F. turns out to be something not only positive but pungent”

Omitted Topics

I should be very glad if people would not draw fanciful inferences from my silence on certain disputed matters…There are questions at issue between Christians to which I do not think we have been told the answer…you cannot even conclude, from my silence on disputed points, either that I think them important or that I think them unimportant. For this is itself one of the disputed points…I have a reluctance to say much about temptations to which I myself am not exposed…

The Roman Catholic beliefs on that subject are held not only with the ordinary fervour that attaches to all sincere religious belief, but…with…chivalrous sensibility that a man feels when the honour of his mother or his beloved is at stake…contrariwise…Protestant beliefs on this subject…it seems that the distinction between Creator and creature (however holy) is imperilled.

[Regarding contraception], I am not a woman nor even a married man, nor am I a priest. I did not think it my place to take a firm line about pains, dangers and expenses from which I am protected; having no pastoral office which obliged me to do so.

The name “Christian”

When a word ceases to be a term of description and becomes merely a term of praise, it no longer tells you facts about the object: it only tells you about the speaker’s attitude to that object… A gentleman, once it has been spiritualised and refined out of its old coarse, objective sense, means hardly more than a man whom the speaker likes

The Hall Analogy

It is more like a hall out of which doors open into several rooms…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…you must be asking which door is the true one; not which pleases you best by its paint and panelling…Are these doctrines true: Is holiness here?…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


1. Why does Jack say that this book not help someone decide between two different denominations? Why did he write the book in this way?

2. Was it a good idea to leave out controversial topics? Why does he say he does this? Do you think this hampers the book?

3. How would you define “Christian”? How does Jack define it? Do you think this is a sufficient definition?

4. Do you find Jack’s “Hall and rooms” analogy helpful when talking about different denominations? What advice does he give for interacting with Christians of other denominations? What do you disagree with and what advice would you add?

Chapter 1 – “The Law of Human Nature”


What quarreling tells us

…the man who makes [these objections] is not merely saying that the other man’s behaviour does not happen to please him. He is appealing to some kind of standard of behaviour which he expects the other man to know about… Quarrelling means trying to show that the other man is in the wrong. And there would be no sense in trying to do that unless you and he had some sort of agreement as to what Right and Wrong are; just as there would be no sense in saying that a footballer had committed a foul unless there was some agreement about the rules of football

Differences in morality

…some people say…different civilisations and different ages have had quite different moralities. But this is not true. There have been differences between their moralities, but these have never amounted to anything like a total difference

…think what a totally different morality would mean. Think of a country where people were admired for running away in a battle, or where a man felt proud of double-crossing all the people who had been kindest to him. You might just as well imagine a country where two and two made five

Not keeping the Moral Law

If we do not believe in decent behaviour, why should we be so anxious to make excuses for not having behaved decently?…you notice that it is only for our bad behaviour that we find all these explanations. It is only our bad temper that we put down to being tired or worried or hungry; we put our good temper down to ourselves


1. What can we learn from two people quarreling?

2. How do explain differences in morality, particular among individuals who have a radically different morality?

3. Do we keep the Moral Law? What does our reaction to the Moral Law tells us about the Law itself?

Chapter 2 – “Some Objections”


Herd Instinct

…[there is] a third thing which tells you that you ought to follow the impulse to help, and suppress the impulse to run away. Now this thing that judges between two instincts…cannot itself be either of them…it usually seems to be telling us to side with the weaker of the two impulses…[and] often tells us to try to make the right impulse stronger

The Moral Law tells us the tune we have to play: our instincts are merely the keys…[a piano] has not got two kinds of notes on it, the ‘right’ noes and the ‘wrong’ ones… There is none of our impulses which the Moral Law may not sometimes tell us to suppress, and none which it may not sometimes tell us to encourage

Social Conversion

…[this takes] for granted that if we have learned a thing from parents and teachers, then that thing must be merely a human invention. We all learned the multiplication table at school…but surely it does not follow that the multiplication table is simply a human convention…[which] might have made different if they had liked?

…some of the things we learn are mere conventions…to keep to the left of the road…and others of them, like mathematics, are real truths. The question is to which class the Law of Human Nature belongs

We do believe that some moralities are better than others… The moment you say that one set of moral ideas can be better than another, you are, in fact, measuring them both by a standard, saying that one of them conforms to that standard more nearly than the other…real Right, independent of what people think

Change in knowledge vs change in morality

You would not call a man humane for ceasing to set mousetraps if he did so because he believed there were no mice in the house


1. Why might some people think that the Moral Law is simply “herd instinct”. How does Jack explain that it is not?

2. How would you respond to someone who said that the Moral Law was simply social convention?

3. How does Jack explain that the cessation of witch-burning is not really a change in morality?

Chapter 3 – “The reality of the Law”


A Moral Law which we break

…the very idea of something being imperfect, of its not being what it ought to be, has certain consequences

The laws of nature, as applied to stones or trees, may only mean ‘what Nature, in fact, does’……the Law of Human Nature tells you what human beings ought to do and do not. In other words, when you are dealing with humans, something else comes in above and beyond the actual facts. You have the facts (how men do behave) and you have something else (how they ought to behave)


…we might try to make out that when you say a man ought not to act as he does, you only mean the same as when you say that a stone is the wrong shape [for your rockery]; namely, that what he is doing happens to be inconvenient to you

A man occupying the corner seat in the train because he got there first, and a man who slipped into it while my back was turned and removed my bag, are both equally inconvenient…I am angry with a man who tries to trip me up even if he does not succeed…In war, each side may find a traitor on the other side very useful. But though they use him and pay him they regard him as human vermin

It means things like…doing school work honestly when it would be easy to cheat…staying in dangerous places when you would rather go somewhere safer, keeping promises you would rather not keep…

Benefiting Society

…decent conduct does not mean what pays each particular person at a particular moment…it means what pays the human race as a whole…[we] see that you cannot have any real safety or happiness expect in a society where every one plays fair, and it is because they see this that they try to behave decently

If a man asked what was the point of playing football, it would not be much good saying ‘in order to score goals’, for trying to score goals is the game itself, not the reason for the game, and you would really only be saying that football is football – which is true, but not worth saying


1. Why does Jack say that it is “odd” that there is a Moral Law which we do not obey?

2. Why can we not say that “rightness” and “wrongness” is simply “whatever if convenient/inconvenient to us”?

3. Why can we not just say that morality is grounded in the good of society?

Chapter 4 – “What lies behind the Law”


Differing worldviews

…matter and space just happen to exist…[which] by some sort of fluke produced creates like ourselves who are able to think

…which is behind the universe is more like a mind…conscious, and has purposes, and prefers one thing to another…

The role of science

…why anything comes to be…and whether there is anything behind the things science observes – something of a different kind – this is not a scientific question

Inside Information

We do not merely observe men, we are men…we have, so to speak, inside information…men find themselves under a moral law, which they did not make, and cannot quite forget even when they try, and which they know they ought to obey

…no more than the architect of a house could actually be a wall… The only way in which we could expect it to show itself would be inside ourselves as an influence or a command trying to get us to behave in a certain way

A third option

…it gives one much of the emotional comfort of believing in God and none of the less pleasant consequences…[the life-force] will never interfere with you like that troublesome God we learned about when we were children. The Life-Force is a sort of tame God… All the thrills of religion and none of the cost.


1. What are the two (or three) main worldviews concerning the origin and meaning of the universe?

2. How does Jack thing we can determine the correct answer?

3. Do you agree with Jack’s assessment of science? How might this impact other proofs for God (e.g. Kalaam).

4. Jack says that the architect of a house can’t be a wall in that house. But doesn’t the Christian Faith say that the architect entered the house and lived there for thirty-three years?

Chapter 5 – “We have cause to be uneasy”


What we can know from the universe

We have not yet got as far as the God of any actual religion… We have only got as far as a Somebody or Something behind the Moral Law…we should have to conclude that He was a great artist (for the universe is a very beautiful place)…but also that He is quite merciless and no friend to man (for the universe is a very dangerous and terrifying place)

What we can know from the Moral Law

…in the Moral Law somebody or something from beyond the material universe…[is] getting at us…the Being behind the universe is intensely interested in right conduct…The Moral Law does not give us any grounds for thinking that God is ‘good’ in the sense of being indulgent, or soft, or sympathetic. There is nothing indulgent about the Moral Law. It is as hard as nails… if there does exist an absolute goodness it must hate most of what we do

Why take this approach?

Christianity tells people to repent and promises them forgiveness. It there has nothing…to say to people who do not know they have done anything to repent of and who do not feel that they need any forgiveness…. When you know you are sick, you will listen to the doctor


1. What can we know about God from the universe?

2. What can we know about God from the Moral Law?

3. Why did Jack take this approach to Christianity? Why start with the Moral Law? What lesson might we take from this in our own apologetics?


These are some of the resources I consulted: CS Lewis Institute QuestionsCS Lewis.Org Study Questions and Mere Christianity Study Guide.

I also listened to the Mere Christianity podcast where a group of evangelical Christians discuss the book in quite some detail. I didn’t always agree with everything they said, but it was certainly thought-provoking and made a five-hour round-trip to LA much more enjoyable 🙂

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