The Genius of C.S. Lewis: Mere Christianity

Given his prodigious output, it’s very hard to succinctly communicate the full genius of C.S. Lewis. Therefore, to give a broader sampling of his wisdom, in this series I’m going to be selecting four of my favourite books by Lewis and then examining some of the ideas to be found between their covers. The books we’ll be looking at will be Mere Christianity, The Great Divorce, The Screwtape Letters, and we’ll then close with The Four Loves.

After The Chronicles of Narnia, Lewis’ most well-known book is his seminal work on apologetics, Mere Christianity. The chapters of this book originally began life as radio broadcasts during World War Two.  Over the course of the book, Lewis defends the Christian worldview. Matt and I go through this book chapter-by-chapter in Season 1 of our podcast, Pints With Jack, although back then the podcast was named after Lewis’ pub, The Eagle and Child.

1. A common Christianity

You don’t have to go far into this book to uncover treasure. For example, readers shouldn’t skip over the Preface of the book because in it Lewis explains what he is attempting to do, which is to defend what he calls “Mere Christianity”. Jack explains that he’s going to ignore denomination disputes and instead focus on explaining and defending the essentials of Christianity.

Although some people describe themselves as “a Mere Christian”, Lewis doesn’t set up Mere Christianity as its own denomination or as an alternative to the ancient creeds of the Church. He simply says that “Ever since I became a Christian I have thought that the best, perhaps the only, 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”. He felt compelled to do this because he thought that few others were defending this.

Lewis argues that this “Mere Christianity” is not a watered-down, vague, unsubstantial lowest-common denominator Christianity. Instead, he casts it as the highest-common factor Christianity, held across denominations and something which is both substantial and challenging. This is a sentiment which can be found in John-Paul II’s 1995 encyclical, Ut Unum Sint, where he quotes Pope John XXIII who said that “What unites us is much greater than what divides us.”

2. Choosing a denomination

Although Lewis purposefully avoids all denominational disputes in Mere Christianity, I think he gives really good advice about denominations.

He asks us to imagine a house. He describes the hallway as Mere Christianity and the rooms as denominations. He says that his goal in his book is to move people from outside the house into the hallway. However, he makes it clear that the hallway is not a place to remain indefinitely. He urges his readers to find their way into one of the rooms where “there are fires and chairs and meals”. 

He cautions us though in the selection of a room. He says “…above all you must be asking which door is the true one; not which pleases you best by its paint and paneling. 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?’”

3. The Moral Law

After the Preface, Lewis spends the first portion of the book arguing for the existence of God and he does this by appealing to our common human experience. 

Jack asks us to think about when we’ve heard people quarrelling. He points out that those who are quarrelling do not merely say that the other person’s behaviour displeases him. He says that “He is appealing to some kind of standard of behaviour which he expects the other man to know about… 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”.

So from this, it appears that there is a Moral Law which exists. Over subsequent chapters Lewis looks at the possible origin for this Moral Law. Is it simply a matter of personal taste? Is it simply cultural convention? Is it simply instinct or taught to us in education? Lewis concludes that none of these are sufficient and starts building a cumulative case that this Moral Law is grounded in Moral Law Giver, God.

4. The Argument From Desire

This isn’t the only argument Jack gives for the existence of God. Although not presented as a formal syllogism in rigorous philosophical terms, he argues that our innate desires point to a world beyond this one. 

He first observes that this world cannot fully satisfy us. Inevitably, it will let us down. “How will we respond when this happens?”, he asks. The hedonist will simply try and consume more – a new wife, a new job, a new car… The stoic will simply try and grin and bear it. Lewis says that the Christian, however, draws a different lesson:

The Christian says, “Creatures are not born with desires unless satisfaction for those desires exists. A baby feels hunger well, there is such a thing as food. A duckling wants to swim: well, there is such a thing as water. Men feel sexual desire: well, there is such a thing as sex. If I find in myself a desire which no experience in this world can satisfy, the most probable explanation is that I was made for another world.

C.S. Lewis, Mere Christianity

Although perhaps not the most rigorous of proofs for God, Dr. Peter Kreeft, I personally find that this argument resonates most deeply with my own personal experience.

5. The Use of analogies

One cannot read Mere Christianity without noticing how often Lewis uses imaginative analogies to bolster his arguments and make different philosophical ideas easier to understand.

For example, in one chapter, Jack breaks down morality into three distinct parts. However, he does so by asking us to imagine a fleet of ships travelling across the ocean. For the fleet to make it safely home, three important factors must be present….

First of all, the ships must remain in formation and not crash into each other. Secondly, the ships themselves must be in good working order so that they can be steered correctly. Lastly, the ships must travel in the right direction in order to make it to their destination. 

Lewis then draws parallels to morality. We must act rightly in relation to each other – we can’t be crashing into each other. We must be rightly-ordered internally – if we can’t control ourselves, it won’t be long before a collision is inevitable. Lastly, we must consider our teleology, our ultimate purpose, which is informed by the Creator who made us.

6. Faith and Works

Rather than stoking the fire of animosity between denominations, Lewis addresses the Reformation issue of the relationship between faith and works in an attempt to affirm what all Christians affirm. 

Which is more important, faith or works? Lewis says that’s like asking which blade in a pair of scissors is more important. Discarding the caricatures of the Protestant and Catholic positions, he quotes St. Paul’s epistle to the Philippians which seems to synthesize both faith and works in a single sentence. He says:

The first half is, “Work out your own salvation with fear and trembling”-which looks as if everything depended on us and our good actions: but the second half goes on, “For it is God who worketh in you” –  which looks as if God did everything and we nothing… You see, we are now trying to understand, and to separate into water-tight compartments, what exactly God does and what man does when God and man are working together. And, of course, we begin by thinking it is like two men working together, so that you could say, “He did this bit and I did that.” But this way of thinking breaks down. God is not like that. He is inside you as well as outside: even if we could understand who did what, I do not think human language could properly express it. In the attempt to express it different Churches say different things. But you will find that even those who insist most strongly on the importance of good actions tell you you need Faith; and even those who insist most strongly on Faith tell you to do good actions.

C.S. Lewis, Mere Christianity

7. Forgiveness

Mere Christianity is not simply a book of dry doctrine. Personally, when I read it, I often find myself challenged concerning the state of my soul. No chapter perhaps best illustrates this better than the chapter on forgiveness.

Lewis says that he used to think that the most unpopular doctrines of Christianity related to sex, but perhaps it is, in fact, Christianity’s teaching of forgiveness. This might surprise us. After all, doesn’t everyone admit that forgiveness is a wonderful thing? Jack says we say this when we are the ones seeking forgiveness. However, when we are the ones who need to do the forgiving, we complain and howl in anger at the injustice of it all! 

Quite rightly, Lewis reminds us that right at the heart of Christianity is the commandment to forgive our enemies, with Jesus’ harsh words concerning those who refuse to forgive. However, Lewis doesn’t leave it there…

Jack says that when he was a child he was told to “Hate the sin, but love the sinner”. He thought this was ridiculous. How was it possible to separate a man from what the bad things that he did? However, he eventually realized that there was one person for whom he had been doing this his entire life…himself. 

He considers Christ’s command to love our neighbour as ourselves. I don’t know about you, but I’ve always focussed on the first part of that sentence, to love my neighbour. However, Lewis invites us to first consider the second part of that sentence…to love my  neighbour as myself. How do I love myself? With a little bit of introspection, we realize that we don’t always like ourselves or the things that we do. This means that when I love my neighbour, I don’t have to pretend that he is nice when he is not, or that the things that he does are good when they are bad. Instead, I have to do for him what I do for myself, seek his good and hope that next time he will make a better choice and ultimately become a better man. 

Christ does not forgive me because I didn’t really do anything wrong. He does so because He is good…and to be a Christian means to forgive the inexcusable because God has forgiven the inexcusable in me.

8. The Trilemma

One of the most well-known passages in Mere Christianity is C.S. Lewis’ “Trilemma”. Lewis did not invent this argument, but he did greatly popularize it.

Lewis is asking the most fundamental question one can really ask: who is Jesus? After all, Jesus made some pretty bold claims, not least of which was the ability to forgive sins. It’s one thing to say that you forgive someone who wrongs you, it’s quite another to tell someone that you forgive them for their sins against other people!

Lewis then addresses the person who says that Jesus was a great moral teacher, but he wasn’t God. Lewis rips this assertion to shreds, saying that this is the one thing which we cannot say! If we assume that the New Testament to be a record of what Jesus Himself said, we only have three options. He was either a liar, a lunatic or the Lord. Lewis explains:

A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic – on a level with the man who says he is a poached egg-or else he would be the Devil of Hell. You must make your choice. Either this man was, and is, the Son of God: or else a madman or something worse. You can shut Him up for a fool, you can spit at Him and kill Him as a demon; or you can fall at His feet and call Him Lord and God. But let us not come with any patronising nonsense about His being a great human teacher. He has not left that open to us. He did not intend to.

C.S. Lewis, Mere Christianity

Lewis liked this argument so much that he reuses it in The Lion, the Witch and the Wardrobe when Professor Kirk explains to the children why they should believe Lucy’s story about finding a magic world in the wardrobe.

9. The Purpose of Christianity

As my podcast co-host Matt and I worked through Mere Christianity chapter-by-chapter, one thing which jumped out at us was Lewis’ assessment of the purpose of Christianity. He says:

It is easy to think that the Church has a lot of different objects — education, building, missions, holding services. Just as it is easy to think the State has a lot of different objects — military, political, economic, and what not. But in a way things are much simpler than that. The State exists simply to promote and to protect the ordinary happiness of human beings in this life. A husband and wife chatting over a fire, a couple of friends having a game of darts in a pub, a man reading a book in his own room or digging in his own garden — that is what the State is for. And unless they are helping to increase and prolong and protect such moments, all the laws, parliaments, armies, courts, police, economics, etc., are simply a waste of time. In the same way the Church exists for nothing else but to draw men into Christ, to make them little Christs. If they are not doing that, all the cathedrals, clergy, missions, sermons, even the Bible itself, are simply a waste of time. God became Man for no other purpose

Mere Christianity

In the last chapter we were considering the Christian idea of “putting on Christ,” or first “dressing up” as a son of God in order that you may finally become a real son. What I want to make clear is that this is not one among many jobs a Christian has to do; and it is not a sort of special exercise for the top class. It is the whole of Christianity. Christianity offers nothing else at all.

C.S. Lewis, Mere Christianity

Lewis sees that the central purpose of Christianity is to become another Christ. This comes about by sharing in God’s divine life. We receive our natural life from our parents, but we receive divine life from God, principally, he says, through faith, baptism and Holy Communion. This brings about a transformation which he compares to tin soldiers coming to life. Although he never uses the term, Lewis is describing theosis, which is a term often used in Eastern Christianity to describe the transformation which comes about when, in the words of St. Peter, we become “partakers of the divine nature”.

So there are some of my favourite themes of Mere Christianity. Next time we’ll be looking at The Great Divorce

3 comments

  • The idea that Christian teaching with regards to forgiveness, properly understood, is harder than chastity is nonsense.

    Like loving one’s enemies, people have a hard time with forgiveness because they don’t know what it is. Like the misconception people have that loving one’s enemies means we have to like them (after all, an enemy is someone who, by definition, you don’t like), people equate forgiveness with the mere letting go of a grudge. That’s a false understanding. From this false understanding flows the error that we are commanded to forgive the unrepentant. Nowhere does Jesus ever say or imply such a thing. He clearly commands us to forgive one who is repentant. Even on the cross where He says, “Father forgive them for they know not what they do.” does not imply that we are commanded to forgive the unrepentant. The fact that he doesn’t say, “I forgive them.” testifies to that. Secondly, by saying “they know not what they do.” implies a lack of culpability on the part of those who put Jesus to death.

    The popular idea in Christian circles that we forgive for own peace of mind is short sighted and actually rather selfish. It’s as though forgiveness is all about us and not about the other person at all. It also makes forgiveness a mere emotional thing when in fact emotions are really irrelevant. Like love, without which forgiveness impossible, it is an act of the will. I am not so much looking just relieve my own burden, I am willing the good of the other. In this light, the well intentioned knee jerk forgiveness we so often hear about can be very detrimental to the other person, particularly if his offense involves grave sin. In that case, we, albeit unwittingly, help put his soul in jeopardy by undermining his incentive to repent and be saved.

    This is not the same as finding an excuse to hold on to a grudge or fester hatred. THAT would be detrimental to our own peace of mind. This is one reason why those who have been harmed deserve justice. Because when they deprived of justice it not only creates an obstacle to healing, it makes it harder to forgive when the offender actually repents.

    Popular notions of forgiveness today often reflect a misguided sense of mercy. This goes to something Lewis says elsewhere about the worst atrocities are those those done to the comfort of the perpetrator’s conscience. He is correct in this.

    After all, an act of contrition, as well as purpose of amendment, is required for absolution in the sacrament of confession. Likewise, genuine forgiveness requires repentance of the one who offends. I don’t think anyone would deny that we cannot be at peace unless we acknowledge and take responsibility for what we have done. To love one’s neighbor, particularly one who happens to be our enemy, as ourselves would seem to require extend the same to him.

    • From this false understanding flows the error that we are commanded to forgive the unrepentant. Nowhere does Jesus ever say or imply such a thing

      I’d say it’s implied throughout! I might offer the reverse challenge: where does Jesus say that we only need to forgive the repentant? This would have considerably lightened the weight of his words. After all, it’s much easier to forgive those who crawl to you dressed in sackcloth and ashes.

      Even on the cross where He says, “Father forgive them for they know not what they do.” does not imply that we are commanded to forgive the unrepentant.

      Are you saying that those who were nailing him to the cross and mocking him were repenting while doing this? :-/

      The fact that he doesn’t say, “I forgive them.” testifies to that.

      That’s quite a leap. Why ask another person to forgive a third party if you yourself don’t forgive them? For example, when people have hurt me in the past, my mother has been livid. Yet I’ve told her to forgive them. Why? Because I myself forgive them. If I didn’t forgive them, I wouldn’t ask her to do it.

      Secondly, by saying “they know not what they do.” implies a lack of culpability on the part of those who put Jesus to death.

      Sure…but it doesn’t suggest in the slightest that they were repentant for their objective evil, so I don’t really see how that helps your case.

      The popular idea in Christian circles that we forgive for own peace of mind is short sighted and actually rather selfish. It’s as though forgiveness is all about us and not about the other person at all

      It’s pretty incontrovertible that harbouring unforgiveness can have negative psychological and physiological consequences. However, more importantly, the Lord tells us what happens to those who do not forgive:

      “For if you forgive men their trespasses, your heavenly Father also will forgive you; but if you do not forgive men their trespasses, neither will your Father forgive your trespasses” – Matthew 6:14-15

      So while self-preservation might not be the most high-minded motivation, it doesn’t seem to me to be a particularly bad one.

      It also makes forgiveness a mere emotional thing when in fact emotions are really irrelevant. Like love, without which forgiveness impossible, it is an act of the will.

      I’d agree forgiveness is an act of the will, but also like love there is an interplay between the will and the emotions. If I act like I love someone, I’m more likely to nurture loving feelings. Likewise, if I will to forgive for someone, I’m increasing the likelihood that any potential anger and bitterness are dissipated.

      In this light, the well intentioned knee jerk forgiveness we so often hear about can be very detrimental to the other person, particularly if his offense involves grave sin

      You’re going to have to explain that, because forgiving someone does not mean that what they did was perfectly fine.

      In that case, we, albeit unwittingly, help put his soul in jeopardy by undermining his incentive to repent and be saved

      I think it might be helpful if you put forward what you think forgiveness actually is… It seems that you think that forgiveness means that there are no consequences to what has happened…which isn’t true.

      This is not the same as finding an excuse to hold on to a grudge or fester hatred. THAT would be detrimental to our own peace of mind.

      I don’t know how someone could let go of a grudge without forgiveness. I’m also not entirely sure how one can love, bless and pray for one’s enemies for very long without forgiving them…

      “Love your enemies . . . bless those who curse you, pray for those who abuse you” – Luke 6:27–28

  • First of all, I’m afraid you are refuting an argument I never made. I never said Jesus says or implied that we are to forgive only the repentant, but that we are not COMMANDED to do so. You say it’s implied throughout, but you offer no citation to support that. And that’s because no such implication exists. In the Gospel of Matthew, right after the Jesus answers Peter’s question about about how often should he forgive one who offends, He immediately launches into the parable about the King and the indebted servants. Both servants acknowledge the debt they owe and even pledge to pay the debt which is a clear indication of repentance. If Jesus ever implied we are commanded to forgive the unrepentant, He would not have included such acknowledgment on the part of the servants. Jesus was not one to be superfluous with words or characters in stories, even when speaking in parables.

    After all, God himself does not forgive the unrepentant. Therefore the idea he would command to do the opposite makes no theological sense. Furthermore, the sin against the Holy Spirit that Jesus EXPLICITLY says will not be forgiven is the sin of final unrepentance.

    Any understanding of forgiveness that does not involve its efficacy is woefully lacking. And if the offending party is not repentant, my forgiveness lacks efficacy.

    You most certainly can let go of a grudge without forgiveness. Absolving or cancelling a debt, which is not just my understanding of forgiveness, but Jesus’ understanding as he points out in the parable, has nothing to do with how I feel about the person, which is what grudges involve. If you think forgiveness automatically wipes out a grudge, I’m afraid you’ve never truly forgiven anyone or held a grudge against someone. If forgiveness did so, there would be reconciliation between the two parties in all cases, which of course there is not. You are quite right when you say forgiveness does not eradicate consequences. Lack of reconciliation is a common one.

    Just as hasty forgiveness of a financial debt can enable the further self-destructive behavior of one who racks up debt, even more so with someone who engages in immorality which, if grave, can put his soul jeopardy. Any forgiveness that does not take the offending party into account is one that is actually far from the Kingdom of God.

    “It’s pretty incontrovertible that harbouring unforgiveness can have negative psychological and physiological consequences”

    I think this flows from a false understanding of psychology, physiology as well as forgiveness. The idea that forgiveness automatically wipes out psychological and physiological pain is ridiculous. Any doctor or therapist who tells a patient any such thing ought to lose their license get their asses sued off for malpractice. Certainly, looking at these things through a spiritual lense is not only helpful but indispensible. As opposed to trying to use forgiveness as a therapuetic short cut, one might offer up their sufferings for the person who did it to them. Offer it up for their repentance so they can be truly forgiven. Now, I am not saying one should not use every morally licit way to alleviate the suffering caused by someone else. But I am saying there is no guarantee they are going to be completely free of their pain in this life, regardless of treatment. One of the most valuable things I have learned about peace is that is often not painless.

    Tim Staples wrote a good article on the subject of forgiving the unrepentant. Given that he takes the same position I do, I may be biased.

    https://www.catholic.com/magazine/online-edition/to-forgive-or-not-to-forgive-that-is-the-question

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