Mere Christianity

Updated: January 23, 2023 Reading Time: 9 minutes
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The Book in 5 Quotes

You cannot find out which view is the right one by science in the ordinary sense. Science work by experiments.

God is the only comfort, He is also the supreme terror the thing we most need and the thing we most want to hide from.

“I’m ready to accept Jesus as a great moral teacher, but I don’t accept His claim to be God.” That is the one thing we must not say. 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 poached egg—or else he would be the Devil of Hell.

If Christianity only means one more bit of a good advice, then Christianity is of no importance. There has been no lack of good evidence for the last four thousand years. A bit more makes no difference.

Every time you make a choice you are turning the central part of you, the part of you that chooses, into something a little different from what it was before. And taking your life as a whole, with all your innumerable choices, all your life long you are slowly turning this central thing either into a heavenly creature or into a hellish creature either into a creature that is in harmony with God, and with other creatures, and with itself, or else into one that is in a state of war and hatred with God, and with its fellow-creatures, and with itself.

Who Should Read It?

Lewis was not a church man so his explanations and descriptions while easy to understand are not condescending as most religious folks are when talking about something they are already convinced about.

I think anyone who is curious about religions in general would find value in the book. Atheists and doubters (like myself) in particular will have a great time debating with Lewis and learning more than a thing or two about Christianity and about themselves.

Summary and Notes

Science and Progress

The modern world seems to be all about “following the science” and “progress”. For tech folks like Jeff Bezos for society not to progress, to stall is the worst possible outcome. Early in the book Lewis talks about the important role science plays without idolizing it when he says

You cannot find out which view is the right one by science in the ordinary sense. Science work by experiments

For science is a discovery process. I’m always suspicious when somebody says “the science is clear” about a fact. Science being science is about experimentation and proving or disproving hypothesis but it can never get to tautologies. Then, on progress Lewis also has a good take that stuck with me. He writes:

We all want progress. But progress means getting nearer to the place where you want to be. And if you have taken a wrong turning, then to go forward does not get you any nearer. If you are on the wrong road, progress means going an about-turn and walking back to the right road.

How can we know humanity is on the right track? Is there a guiding thread, a guiding principle? Or as doom-sayers have warning us, we’re on the brink of a climate apocalypse and humanity is going to end soon?

If we can’t rever science nor trust completely that we’re making progress, what can we do? Lewis turns to religion, to God. And to those doubting the existing of a superior power he poses an interesting but not irrefutable metaphor:

If there was a controlling power outside the universe, it could not show itself to us as one of the facts inside the universe—no more than the architect of a house could actually be a wall or staircase or fireplace in that house. 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.


Lewis is right when he says “Atheism turns out to be too simple”. I’m with Sartre on this one with his notion of existential choice. We are always choosing. Deciding not to choose is also a choice. We are always picking sides even when we think we are not.

But also, as Lewis writes, the fact that we can make a choice between believing there is a superior power and deciding the universe has no meaning has a deeper meaning:

If the whole universe has no meaning, we should never have found out that is has no meaning: just as, if there were no light in the universe and therefore no creatures with eyes, we should never know it was dark. Dark would be a word without meaning.

Religion is all about opposites and paradoxes

One thing that has always fascinated me about religious discourse and religious texts is their use of parables, metaphors and paradoxes to teach and explain things. Lewis is no exception, resorting to paradoxes throughout the book:

God is the only comfort, He is also the supreme terror the thing we most need and the thing we most want to hide from.

The powers which enable evil to carry on are powers given it by goodness.

A man can eat his dinner without understanding exactly how food nourishes him. A man can accept what Christ has done without knowing how it works indeed, he certainly would not know how it works until he has accepted it

Only a bad person needs to repent: only a good person can repent perfectly. The worse you are the more you need it and the less you can do it. The only person who could do it perfectly would be a perfect person—and he would not need it.

A live body is not the one that never gets hurt, but one that can to some extent repair itself. In the same way a Christian is not a man who never goes wrong, but a man who is enabled to repent and pick himself up and begin over again after each stumble.

A Christian society is not going to arrive until most of us really want it: and we are not going to want it until we become fully Christian.

When a man is getting better he understands more and more clearly the evil that is still left in him. When a man is getting worse he understands his own badness less and less.

Christ, because He was the only man who never yielded to temptation, is also the only man who knows to the full what temptation means.

Society and Morality

Christian morality has a lot of what the Greek stoics called “sympatheia”, the interconnectedness of everything in the universe. Lewis write that “Christianity thinks of human individuals not as mere members of a group or items in a list, but as organs in a boy—different from one another and each contributing what no other could.”

Everything and everybody are connected. More than 2,000 years ago, roman emperor Marcus Aurelius was touching on the same universal point when he wrote:

That which is not good for the bee-hive cannot be good for the bees.


The universe made rational creatures for the sake of each other, with an eye toward mutual benefit based on true value and never for harm.

Lewis echoes Aurelius sentiment when he writes that for Christians, humanity needs to be though of as a “band playing a tune. To get a good result, you need two things. Each player’s individual instrument must be in tune and also each must come in at the right moment so as to combine with all others.”

Using society as a guiding principle, Lewis then summarizes Christian morality as being mainly concerned with three things:

  • “Fair play and harmony between individuals”
  • “Tidying up or harmonizing the things inside each individual”
  • “The general purpose of human life as a whole: what tune the conductor of the band wants it to play”

Sexuality and Marriage

Barred some now retrograde notions about women (which would get Lewis cancelled in our current society), Lewis views of Christian marriage are very sensible.

First he tells something that I think a lot of devout Christians get wrong about their body Christianity is almost the only one of the great religions which thoroughly approves of the body—which believes that matter is good, that God Himself once took on a human body, that some kind of body is going to be given to us even in Heaven and is going to be an essential part of our happiness, our beauty and our energy.

Then he makes a nice analogy between eating and sexual pleasure that stands in stark contrast with what most pious folks would think:

The Christian attitude does not mean that there is anything wrong about sexual pleasure, any more than about the pleasure of eating. It means that you must not isolate the pleasure and try to get it by itself, any more than you ought to try and get the pleasures of taste without swallowing, and digesting, by chewing things and spitting them out again.

Then on marriage he has some excellent advice:

A man and wife are to be regarded as a single organism.

Knowledge can last, principles can last, habits can last; but feelings come and go.

Love—love as distinct from “being in love”—is not merely a feeling. It is a deep unity, maintained by the will and deliberately strengthened by habit

Lastly, his view on divorce stands also in stark opposition with what I grew up hearing from prominent religious folks and I totally agree with:

A great many people seem to think that if you are a Christian yourself you should try to make divorce difficult for every one. I do not think that. At least I know I should be very angry if the Mohammedans tried to prevent the rest of us from drinking wine.

Christianity (or any religion) should not be easy

To end, Lewis has a lot to say about those who think religion can or should be easy. Being a Christian is a way of life and it is not enough to treat Jesus Christ as a “moral teacher”. To be a practicing Christian you must live a Christian life:

Fine feelings, new insights, greater interest in ‘religion’ mean nothing unless they make our actual behaviour better

Or as Chateaubriand asserts in The Genius Of Christianity, “religion is about mystery and sacrifice.”