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Trade Paperback
226 pages
Mar 2004
InterVarsity Press

Mere Theology: A Guide to the Thought of C.S. Lewis

by Will Vaus

Review  |   Author Bio  |  Read an Excerpt



    1. Defending the Faith
    2. Scripture
    3. The Three-Personal God
    4. God's Sovereignty and Human Responsibility
    5. Creation
    6. The Fall
    7. The Person and Work of Christ
    8. The Holy Spirit
    9. Forgiveness of Sins
    10. Faith and Works
    11. Satan and Temptation
    12. The Tao
    13. Venus
    14. Marriage and Divorce
    15. Men Are from Mars
    16. I Am the King's Man
    17. What's Love Got to Do with It?
    19. The Church
    20. Prayer
    21. The Sacraments
    22. Hell
    23. Purgatory
    24. Heaven
    25. The World's Last Night
    Subject Index
    Scripture Index

Chapter 1


C. S. LEWIS IS PERHAPS BEST KNOWN TODAY as the author of the children’s books The Chronicles of Narnia. However, he has also been widely revered as the greatest Christian apologist of the twentieth century. Chad Walsh, in the first published study of the man and his work, called C. S. Lewis “the apostle to the skeptics.” An apologist is one who gives a defense, in this case a defense of the Christian faith. There are four prongs to Lewis’s defense of Christianity. We will examine each of them in turn: the argument from longing, the argument from morality, the argument from reason and the argument from Christ.

However, before we examine his arguments in defense of Christianity, we must recognize something that was quite clear to Lewis: we cannot prove the existence of God. C. S. Lewis once wrote about this in a letter to a young agnostic, Sheldon Vanauken. Lewis maintains that there is not a demonstrative proof of Christianity or of the existence of matter or of the good will and honesty of his best and oldest friends. He suggests that all three are (except perhaps the second) far more probable than the alternatives. He asks whether God is even interested in the kind of theism that would be a compelled logical assent to a conclusive argument. Are we interested in it in personal matters? We demand from our friends a trust in our good faith that is certain without demonstrative proof. It wouldn’t be confidence if our friends waited for rigorous proof. He cites two examples from literature. Othello believed in Desdemona’s innocence when it was proved, but that was too late. Lear believed in Cordelia’s love when it was proved, but that was too late. The magnanimity, the generosity that will trust on a reasonable probability, is what God requires of us in our relationship to him Lewis as an apologist never seeks to prove God. What he does seek to do is to demonstrate the reasonable probability of Christianity. As Lewis points out, the reasoning process is based upon intuition as well as logic. One cannot manufacture rational intuition by argument. There are certain things that must simply be “seen.”2 Furthermore, if Christianity is true, then there comes a time when “you are no longer faced with an argument which demands your assent, but with a Person who demands your confidence.”3 And Lewis knew quite well the importance for the apologist of falling back from the web of argument into the reality of Christ.4 That being said, let us now examine Lewis’s arguments for the reasonableness of the faith.


Lewis’s argument from longing appears in the first book he wrote after becoming a Christian: The Pilgrim’s Regress. In that book he calls this longing romanticism. In the afterword to the third edition of The Pilgrim’s Regress he defines terms. What he means by romanticism is a particular recurrent experience that dominated his childhood and adolescence, which he called romantic because inanimate nature and marvelous literature were among the things that evoked it. The experience was one of intense longing. It is distinguished from other longings by two things. First, though the sense of desire is acute and even painful, the mere wanting is felt to be somehow a delight. This hunger is better than any other fullness; this poverty is better than all other wealth. Second, there is a peculiar mystery about the object of this desire. Inexperienced people suppose they know what they want when they feel this longing. Thus if it comes to a child while he is looking at a far off hillside he at once thinks, “If only I were there.” If it comes when he is remembering some event in the past, he thinks: “if only I could go back to those days.” If it comes while a young man is reading a romantic tale or poem, he thinks he is wishing that such places really existed and that he could reach them. If it comes to an adolescent in a context with erotic suggestions, he believes he has a desire for the perfect beloved. If he discovers literature that treats of spirits and the like with some show of serious belief, he may think that he is desiring real magic and occultism. When it darts out upon him from his studies in history or science, he may confuse it with the intellectual craving for knowledge. But every one of these impressions is wrong. The only merit Lewis claims for his book is that it is written by one who proved false all these ways of trying to satisfy the deepest longings of the heart.5

In The Pilgrim’s Regress, John, the chief character, longs for an island in the west that he has seen in a vision. His longing for the island leads him on a journey far from his home in Puritania and far from the Landlord (God). However, when John reaches the island he finds out that it is merely the back side of the mountains of the Landlord and that he must retrace his steps in order to arrive once again at his real home.

Lewis communicates the power of longing in John’s first vision of the island in The Pilgrim’s Regress. There comes to John from behind him the sound of a musical instrument, very sweet and very short, and after it a full, clear voice—so high and strange that John thinks it is very far away, farther than a star. The voice says, “Come.” Then John sees that there is a stone wall beside the road. However, this garden wall is unique in that it has a window in it. There is no glass in the window, and there are no bars; it is just a square hole in the wall. Through it he sees a green wood full of primroses, and he remembers suddenly how he went into another wood to pull primroses, as a child, very long ago—so long that even in the moment of remembering the memory seems still out of reach. While he strains to grasp it, there comes to him from beyond the wood a sweetness and a pang so piercing that instantly he forgets his father’s house and his mother, and the fear of the Landlord, and the burden of the rules. “All the furniture of his mind is taken away.” A moment later he finds himself sobbing. The sun has gone in. He cannot quite remember what has happened, whether it had happened in this wood or in the other wood when he was a child. It seems to him that through a mist he has seen a calm sea, and in the sea an island, where the smooth turf slopes down unbroken to the bays.6

There is probably no more dominant theme in all of Lewis’s writings than this theme of longing, or what the Germans call sehnsucht, or what Lewis came to call joy. The theme appears in his sermons, like The Weight of Glory, where he says that he feels a certain shyness in regard to speaking of this longing. He says that he is trying to rip open the inconsolable secret in each of his listeners, a secret that pierces with such sweetness that when the mention of it becomes imminent, we grow awkward and affect to laugh at ourselves. It is a secret we cannot hide and cannot tell, though we desire to do both. We cannot tell it because it is a desire for something that has never appeared in our experience. Again, the books or the music in which we thought the beauty was located will betray us if we trust them. The beauty is not in them, it only comes through them, and what comes through them is longing. Beauty and the memory of our past are good images of what we really desire, but if they are mistaken for the thing itself, they turn into dumb idols, breaking the hearts of their worshipers. These images are not the thing itself; they are only the scent of a flower we have not picked, the echo of a tune we have not heard, news from a country we have not yet visited.7

The theme of longing also appears in Lewis’s children’s stories. The existence of the magical land of Narnia, and the fact that the children cannot get there whenever they want to, creates in them a longing. Within the stories, the experience of this joyful longing appears over and over again. In The Lion, the Witch and the Wardrobe Lewis describes what happens when the children from our world first hear the name of Aslan. Each one of the children feels something jump inside him or her. Edmund feels a sensation of mysterious horror. Peter feels suddenly brave and adventurous. Susan feels as if some delicious smell or delightful strain of music has just passed by her. Lucy gets the feeling you have when you wake up in the morning and realize that it is the first day of summer vacation.8

In his autobiography, Surprised by Joy, Lewis sums up the manner in which this longing led him to Christ. The longing started in childhood and came to him on various occasions. It came to him first as he was standing beside a flowering currant bush on a summer day, then when his brother brought a toy garden into the nursery, again while he was reading Beatrix Potter’s Squirrel Nutkin, and later while he was reading Longfellow’s Saga of King Olaf. Lewis asserts that the central story of his life is all about this unsatisfied desire, which is itself more desirable than any other satisfaction. He calls it joy, which is to be sharply distinguished from happiness and from pleasure. Joy (in Lewis’s sense) has indeed only one characteristic in common with happiness and pleasure: the fact that anyone who has experienced it will want it again. Apart from that, Lewis’s joy might almost equally be called a kind of unhappiness or grief. However, it is a kind we want. Anyone who has tasted it won’t want to exchange it for all the pleasures in the world.9

In the end, however, Lewis concludes that this joy is valuable only as a pointer to something other and outer. It is valuable only insofar as it points us to God. While we are lost, joy naturally looms large in our thoughts, just as when we are lost in the woods the sight of a signpost is a great matter. But when we have found the main road and are passing signposts every few miles, we don’t stop and stare anymore. The signposts encourage us, and we should be grateful to the authority that set them up, but we shouldn’t get caught up in staring at signposts for the rest of our lives. Joy is a signpost to the new Jerusalem that should encourage us to continue on our way.10

After becoming a Christian, Lewis turned around and began using this joy, this longing, this experience of sehnsucht that led him to Christ, to lead others to Christ. In his afterword to The Pilgrim’s Regress, he describes how longing is an argument for Christianity. According to Lewis, if a person diligently follows desire and resolutely abandons false sources when their falsity appears, that person will come out at last into the clear knowledge that the human soul was made to enjoy some object that is never fully given in our present mode of experience.11 The longing that all human beings experience for something that cannot be had in this world suggests that we were made for another world, or for Someone outside of this world, namely, God.

Lewis uses this argument in a letter to Sheldon Vanauken. He asks Vanauken what the existence of a wish suggests. Lewis comments about how he was once impressed by Arnold’s line “Nor does the being hungry prove that we have bread,” but then he takes issue with the statement. Though being hungry doesn’t prove that one particular person will get food, it does prove that there is such a thing as food! If we were a species that didn’t normally eat, weren’t designed to eat, would we feel hungry? If we are really the products of a materialistic universe, how is it we don’t feel at home in it? Do fish complain about being wet? If they did, wouldn’t that suggest that they had not always been, or would not always be, purely aquatic creatures? Lewis calls attention to how we are perpetually surprised at time. “How time flies! Fancy John being grown-up and married! I can hardly believe it!” Why can’t we believe it?

The reason is because there is something in us that is not temporal.12 The fact that we have a desire for something or someone that cannot be satisfied by anything or anyone in this world suggests that there is something or someone outside of this world who can satisfy our desire. As Blaise Pascal said, there is a God-shaped vacuum in the heart of every person. The existence of this vacuum, and the experience of intense longing for something that cannot be had in this world, both suggest that there is a God. Ecclesiastes 3:11 says that God “has also set eternity in the hearts of men.” We all have a desire for timelessness. The argument from longing is one of the most powerful arguments for the existence of the supernatural realm, and Lewis is perhaps the best conveyor of this argument in modern fiction and nonfiction.


The second prong of Lewis’s defense of Christianity consists of the argument from morality. This is the first argument that Lewis uses to defend the existence of God in his Broadcast Talks, later reprinted as the first two books of Mere Christianity.

The first book of Mere Christianity is entitled “Right and Wrong as a Clue to the Meaning of the Universe.” The first thing Lewis does in this book is demonstrate from everyday experience the existence of ultimate right and wrong.

First, Lewis argues, the fact that there is ultimate right and wrong is seen in the way people quarrel with each other. When people quarrel with each other they always appeal to some sense of ultimate right and wrong. We can see this even with children. One of their favorite phrases is, “That’s not fair!” Children have a sense of ultimate fairness, of ultimate right and wrong that is imprinted on their minds.

People who quarrel say things like, “I was there first. What gives you the right to push your way in?” Or they say, “I gave you one of my cookies, so you should share one of your crackers with me.” Or else, “Honey, you promised that you would get the car washed! Now you better live up to your promise.” The point of quarreling is to determine who is at fault, and you can’t determine who is at fault unless there is right and wrong.

Second, Lewis points out that at some stage in the quarrel someone may offer an excuse for their behavior, but that in no way eliminates ultimate right and wrong. The person offering the excuse tries to show why his or her behavior was not in the wrong. People try to establish why they had a right to take the first person’s place or why they shouldn’t share their crackers, or they introduce an intervening event that relieves them from keeping their promise. Seldom does the person offering the excuse disagree with the other person’s standard. Both of them know there is a right way to behave and a wrong way to behave. If we do not believe in ultimate right and wrong, then why do we spend so much time trying to prove that our behavior is right? Isn’t it because we do believe there is ultimate right and wrong, and we desperately want to be found in the right?

Next Lewis answers the objection of those who claim that this sense of ultimate right and wrong is merely instinct. They say, “Isn’t our sense of right and wrong just our herd instinct?” The answer is no; we have something more than instinct operating here.

Suppose you see someone in danger, or someone who is drowning and no one else is around to help. Your first instinct may be to help the person who is in danger or who is drowning because that person is a human being just like you, and that’s what you would want if the situation were reversed. That is your herd instinct coming into play. In the next second, however, you will be thinking that you don’t want to get involved because you don’t want to get hurt. That is your instinct of self-preservation. Our instincts are often in conflict with one another, and over and above our instincts we often hear another voice, the voice of conscience, telling us what we should do. As in the situation above, our conscience would tell us that we should help the person who is in trouble. Interestingly enough, often our conscience will tell us to obey the weaker of our instincts, as in the case above. This shows that the sense of ultimate right and wrong is more than just instinct.

Furthermore, Lewis posits, if ultimate right and wrong were merely matters of instinct, then we ought to be able to point to some instincts that are always right and some that are always wrong. We cannot do that. Sometimes it is right to follow certain instincts in certain situations, while it is wrong to follow those same instincts in other situations. Take our instinct to fight. We would all recognize that sometimes it is right to fight to defend self or family, but someone who fights all the time we call a bully. Arguably, in this instance, there is a sense of ultimate right and wrong impinging upon our instincts. Lewis suggests that our instincts are like keys on a piano, neither right nor wrong in and of themselves. However, there is a right or wrong time to hit a certain key depending upon the piece of music you are playing. The moral law is like the sheet music that tells us which notes to play at what time.

Lewis goes on to answer the objection of those who claim that morality is merely a social contract. They say that societies have decided for themselves what is healthy for maintaining that society, but there is no ultimate right and wrong. It is all a matter of social convention. However, if you really want to maintain that morality is merely a social contract, then you have to be willing to accept the end result: if morality is merely a social contract, then what Hitler did was acceptable. If there is no ultimate right and wrong, then we have no means by which we can say that what Hitler did, by gassing six million Jews, was wrong. Most, if not all people, find this conclusion unacceptable. Why? Because a sense of ultimate right and wrong is ingrained in our very being.

Lewis also notes that the existence of ultimate right and wrong is evidenced by the great similarity between the moral codes of numerous cultures. Some people try to say that different cultures and civilizations have had different moralities, but this is not true. In the appendix to The Abolition of Man, Lewis shows the similarities between the moral codes of the major cultures of human history.

Lewis invites us to imagine a country where people are admired for running away in battle, or where a person feels proud of double-crossing all the people who have been kindest to him or her. He asserts you might as well try to imagine a country where two and two make five. People have differed with regard to which people you ought to be unselfish: should you be unselfish just to your family, or your fellow citizens, or everyone? But human beings have always agreed that you ought not to put yourself first. Selfishness has never been admired. Men have disagreed as to whether you should have one wife or four, but they have always agreed that you must not simply have any woman you want.13

Lewis maintains that there is a law of human nature, which transcends all cultures and points to the validity of the religious worldview vs. the materialist worldview. By “the Law of Human Nature” Lewis means the law of right and wrong. The existence of this law of human nature suggests that there is a Mind behind the universe, a Lawgiver who wants us to behave in a certain way. The existence of the moral law suggests a Mind behind the universe that is very interested in right conduct. In that sense, we can agree with the account given by Christianity, and some other religions, that God is good. But, Lewis says, we must not go too fast here. The moral law does not give us any ground for thinking that God is good in the sense of being indulgent, soft or sympathetic. There is nothing soft about the moral law. It is as hard as nails. It is no use, at this point, saying that a good God is a God who can forgive. You are going too quickly. Only a Person can forgive. And we have not gotten as far as a personal God—only as far as a power behind the moral law and more like a mind than it is like anything else. However, this Mind may still be very unlike a Person.14

This is as far as Lewis’s argument from morality will take us in our search for ultimate reality. First, we know from history, experience and conscience that there is ultimate right and wrong. Second, we know that we have all done wrong. Third, the existence of ultimate right and wrong points to a Mind that is behind the moral law. That is all that the moral law can tell us.


The third prong of Lewis’s defense of Christianity is his argument from reason. His primary work containing this argument is Miracles. His central argument in the book is that naturalism contains a great self-contradiction. He quotes Professor Haldane in support of his view: “If my mental processes are determined wholly by the motions of atoms in my brain, I have no reason to suppose that my beliefs are true . . . and hence I have no reason for supposing my brain to be composed of atoms.”15 If the naturalists are right and nature is all there is, then this begs the question, from where does reason come? Lewis posits that reason can only come from outside of nature. If nature is all there is, then there is no purpose behind the existence of the universe. If there is no purpose, then there is no reason. If there is no reason, then all arguments for or against naturalism are nonsensical and thus invalid.

Lewis’s argument for the self-contradiction inherent in naturalism received criticism from Elizabeth Anscombe, later professor of philosophy at Cambridge. The criticism came in the form of a debate during a Socratic Club meeting in Oxford on February 2, 1948.16 The particular statement in the first edition of Miracles to which Anscombe objected was Lewis’s statement that “we may in fact state as a rule that no thought is valid if it can be fully explained as the result of irrational causes.”17 Anscombe insisted that a distinction should be made between irrational causes (such as passion, self-interest, obstinacy and prejudice) and nonrational causes (such things as brain tumors, tuberculosis and mental fatigue). She asked Lewis to clarify what he meant by the word valid. Anscombe also distinguished between the ground of a conclusion (the reasons a person would give if asked to explain why one thinks such and such) and the cause of a conclusion (brain tumors, prejudices or whatever makes one think as one does). Lewis admitted in the course of debate that his use of the word valid was unfortunate.18

After the debate, Lewis was dejected. He told George Sayer that he felt his argument for the existence of God had been demolished.19 However, Lewis did some further thinking on the whole issue of naturalism, which resulted in his rewriting chapter 3 of Miracles for the 1960 Fontana paperback version.20

Some Lewis scholars maintain that after the debate with Anscombe, Lewis made a deliberate decision to no longer write any strictly theological or apologetic works.21 Sayer maintains that Lewis told him, with regard to Miracles, “I can never write another book of that sort.”22 Obviously, though, after Lewis thought the matter through, he did not give up on classical apologetics, as he did rewrite that chapter in Miracles, and that only a few years before his death. Though it seems Lewis was humbled by the encounter with Anscombe, he clearly continued to be a believer in Christ. Furthermore, he continued to stand by his early defenses of the Christian faith up to the time of his death. However, it would appear that after the debate with Anscombe, Lewis recognized the greater strength of intuitive and imaginative ways of leading people to faith in Christ, over and above his earlier and more strictly logical approach in his broadcast talks. Thus Lewis came to write The Chronicles of Narnia in order to “baptize the imaginations” of children.

At any rate, Lewis’s argument from reason may be summed up as follows: If there is no reason, then the statement that there is no reason is unreasonable. If reason does exist, then it points to the reality of the supernatural realm. In Mere Christianity Lewis writes that atheism is too simple. If there is no meaning to the universe, we should never have found it out—just as, if there was no light in the universe and therefore no creatures with eyes, we would never know it was dark. The word dark would have no meaning.


The fourth and most crucial prong of Lewis’s defense of Christianity is his argument from Christ. In the second book of Mere Christianity, entitled “What Christians Believe,” this line of argument follows Lewis’s argument from morality. However, when Lewis begins to talk of Christ, he takes us a step further, a step higher, than we could possibly go in following his other arguments for the faith. The way of knowing truth through Christ is far more direct than the way of knowing truth through morality, reason or even through longing. At this point it might be said that we begin to move from “the logic of speculative thought” into “the logic of personal relations.”24

Lewis spends the first two and one half chapters of “What Christians Believe” setting the stage for the argument from Christ. He briefly examines a few different “rival conceptions of God”: atheistic materialism, pantheism, modernist Christianity (what Lewis calls Christianity-and-water), dualism and the Christian idea of God.

Lewis’s final evaluation of atheistic materialism has already been mentioned above. Lewis rejects pantheism because it talks nonsense. The pantheist says that if you could only see cancer or a slum from the divine point of view, you would realize that it also is God.25 Lewis calls this “damned nonsense.” He rejects pantheism because it flies in the face of our deepseated sense of right and wrong.

Lewis rejects Christianity-and-water because it is too simple. This conception of God asserts that there is a good God in Heaven; therefore all is right with the world. This leaves out the terrible doctrines of sin, hell, the devil and redemption. Lewis maintains it is no good asking for a simple religion because real things are not simple.26

Lewis claims that there are only two conceptions of God that face all the facts: the Christian one and dualism. What are the facts that must be faced? The facts are these: that the universe contains much that is obviously bad and apparently meaningless, and there are creatures like ourselves who know that it is bad and meaningless.27 According to Lewis, only dualism and Christianity face these facts head on.

Dualism is the belief that there are two equal and independent powers behind the universe, one good and the other evil. However, the question that must be asked in regard to dualism is, Why do we call one power good and the other evil? When we call one power good and the other evil, we may be declaring our preference for good over evil. If this is the case, then we ought to give up talking about good and evil and make it clear that we are talking only about our preferences. The other alternative is to say that there really is good and evil. If there is good and evil, then by what standard are we judging? Whatever the standard, it is higher up than either good or evil, therefore the higher standard should be called God. Thus dualism falls apart.

The other problem with dualism is that a person cannot be bad for the mere sake of badness, but a person can be good for the mere sake of goodness. As Lewis notes, goodness is original; badness is only goodness corrupted. 28 Therefore dualism does not make full sense of the universe as we know it.

According to Lewis, the only conception of God that makes full sense of the universe is the Christian one, though the Christian view comes very close to dualism. Christianity maintains that God created everything good and then some of his creation chose to set up on its own, thus becoming evil. The difference between Christianity and dualism is that Christianity believes that God created the Dark Power, or the devil. However, Christianity agrees with dualism that this world is at war. This world is “enemy-occupied territory.” Christianity is the story of how the rightful King of this world has landed here in disguise and is calling on us to take part in his plan of sabotage against the Dark Power.

In the chapter of Mere Christianity titled “The Shocking Alternative,” Lewis answers the question, is this state of affairs (the battle of good against evil) in accord with God’s will or not? He points out that God has not desired that evil should exist, but he has allowed it. Why? Because of free will. Why has God given free will to his creatures? Because without free will, human beings cannot love, for love is a choice.29

The second major question Lewis answers in this chapter is, What has God done in response to evil? Lewis tells us that God has done four things. First, he has left us with conscience. Second, he has left us what Lewis calls good dreams—the myths of various ancient societies that tell of a god who dies and comes to life again thereby giving new life to men. The third thing God has done in response to evil is hammer into one group of people, the Jews, that there is only one God and that he cares deeply about right conduct. The final thing God has done—and here is the real shock—is that he has become a man.

Thus Lewis leads into his christological argument for the probability of Christianity. The argument runs like this. (1) Among the Jews there turns up a man who goes about talking as if he was God. He claims to forgive sins. He says that he has always existed. He says that he is coming to judge the world at the end of time. (2) Such claims as Jesus made would not be unusual among pantheists, who believe that everyone is a part of God. But Jesus, being a Jew, would not have had this pantheistic concept of God in mind. What Jesus claimed is shocking because he was claiming to be the One outside the world who created it and was wholly different from any part of his creation.30 (3) Therefore there are only three alternatives: either Jesus was a madman, something worse or the Son of God.

The “something worse” that Lewis suggests Jesus was, if he was not God or a madman, is that Jesus was a diabolical liar. Another apologist, Josh McDowell, writing many years later but building on Lewis’s argument, presents us with a similar trilemma: either Jesus was a liar, a lunatic or Lord and God.31 What Lewis does is to show us forcefully that a man like Jesus, who claimed to be God by his words and deeds, could not simply have been a great moral teacher. That is not an option left open to us.

Lewis contends that it is obvious to him that Jesus was neither a lunatic nor a fiend. These options are not consistent with Jesus being one of the greatest, if not the greatest of, moral teachers of all time. Therefore Lewis concludes that Jesus must be God.

However, those who have heard and seriously considered Lewis’s argument from Christ raise some valid questions. How do we know that the presentation of Jesus’ words and deeds in the New Testament is accurate? Couldn’t it all be legends? Some people suppose that Lewis did not even consider such questions as these, but that is not the case. Lewis was well aware of various modern attacks on the historicity of the New Testament picture of Jesus. We will examine Lewis’s response to those attacks in the next chapter.