Mere Christianity

Summary

Mere Christianity is C. S. Lewis's case for, and plain explanation of, the beliefs held in common by Christians of most denominations. In the preface Lewis borrows the phrase "mere Christianity" from the Puritan writer Richard Baxter and compares the shared faith to a hall from which doors open into the rooms of the separate churches; he says he is describing the hall, not recommending a room, and that people must eventually live in a room rather than in the hall. Book I, Right and Wrong as a Clue to the Meaning of the Universe, starts from quarrels. People who argue about fairness appeal to a standard they expect the other person to know, which Lewis calls the Law of Human Nature or Moral Law. He answers the objections that it is only herd instinct or social convention, argues that it is not a description of how people behave but of how they ought to, and concludes that behind it stands a mind more like a lawgiver than like anything in nature. Because everyone breaks this law, he ends the first book by saying that we have real cause for concern before that lawgiver. Book II, What Christians Believe, sets Christianity against atheism, pantheism and dualism, and describes the world as enemy-occupied territory into which the rightful king has landed in disguise. In the chapter called The Shocking Alternative Lewis argues that Jesus' claims to forgive sins and to have always existed leave no room for calling him merely a great moral teacher: he was a lunatic, something worse, or the Son of God. He then presents the atonement as the perfect penitent doing for humanity what it could not do for itself, and names baptism, belief and the Lord's Supper as the means by which the new life is passed on. Book III, Christian Behaviour, compares morality to a fleet of ships that must avoid collisions, keep each ship seaworthy and know where it is going. Lewis treats the four cardinal virtues, social morality, psychoanalysis and moral choice, sexual morality and Christian marriage, and forgiveness, and he calls pride the great sin, the vice from which all others grow. He closes with chapters on charity, hope and faith. Book IV, Beyond Personality, explains the Trinity through the difference between begetting and making, time and eternity, and the image of tin soldiers being turned into living men. Lewis argues that God's aim is not to make people nicer but to make them new creatures, sons of God, and that the self is found only by giving it up. The four books began as BBC radio talks between 1941 and 1944, were printed as Broadcast Talks (1942), Christian Behaviour (1943) and Beyond Personality (1944), and were revised and joined under the present title by Geoffrey Bles in London in 1952.

Plot or Argument

• Preface: the hall and the rooms

  Lewis explains that he will set out only the beliefs common to nearly all Christians, borrowing Baxter's phrase mere Christianity, and avoids disputed questions between the churches, sending readers on to the rooms of particular communions.

• Book I: The Moral Law as a clue

  From everyday quarrels Lewis argues that human beings share a sense of a law they did not invent and do not keep; he rejects explaining it as instinct or mere convention and infers a moral mind behind the universe, before whom every lawbreaker stands accountable.

• Book II, chapters 1-2: Rival conceptions and the invasion

  Lewis weighs atheism, pantheism and dualism, argues that evil is a spoiled good rather than an equal power, and describes the world as occupied territory into which God has sent his Son to reclaim it.

• Book II, chapters 3-5: The shocking alternative

  Lewis presents the claim that Jesus must be judged mad, wicked or divine, describes the atonement as the perfect penitent's surrender on humanity's behalf, and points to baptism, belief and Holy Communion as the channels of the new life.

• Book III, chapters 1-7: Morality, virtue and marriage

  The fleet image divides morality into fair play between persons, harmony within the self and the purpose of life; Lewis then treats prudence, temperance, justice and fortitude, a Christian society, psychoanalysis and moral choice, chastity, marriage and forgiveness.

• Book III, chapters 8-12: Pride and the theological virtues

  Lewis names pride as the great sin and the source of other vices, then writes on charity as an act of will, on hope as the longing for heaven, and on faith in two senses, holding to belief through changing moods and trusting God entirely.

• Book IV: Beyond Personality

  Lewis explains the Trinity through begetting and making and through God beyond time, describes the Christian life as a good infection passed from Christ, and argues that God means to turn creatures into sons, so that nice people are not the goal but new men.

Characters

• C. S. Lewis, speaker

  The Oxford don addressing a wartime radio audience in a plain, conversational voice, often confessing his own former unbelief.

• Jesus Christ, subject of Book II

  The figure whose claims Lewis argues cannot be reduced to those of a moral teacher, and whose life is the pattern of the new humanity in Book IV.

• Richard Baxter, source of the title

  Seventeenth-century Puritan pastor whose phrase "mere Christian" Lewis adopts in the preface.

• The listener, implied addressee

  An ordinary, often doubtful member of the public, whose objections Lewis states and answers in turn.

Lessons

• Arguing from the quarrel to the lawgiver

  Lewis's opening argument does not begin with Scripture or miracles but with an ordinary dispute about fairness. He asks the reader to notice that both sides assume a shared standard, and builds his case from there. The method shows how a persuasive argument can start from what the audience already grants.

  • What does Lewis think people reveal when they say 'That's not fair'?
  • How does Lewis answer the objection that the Moral Law is only herd instinct?
  • Does a shared moral sense require a lawgiver, or could it be explained another way?

• The trilemma and its critics

  In Book II Lewis argues that Jesus' claims leave only three options: madness, deception or divinity. The argument became famous and was also widely disputed; philosophers and New Testament scholars have asked whether the options are complete and whether the Gospel sayings are reported exactly. Students can study both the argument and the replies as an exercise in testing premises.

  • Which sayings of Jesus does Lewis treat as claims to be God?
  • What further options have critics proposed, and how might Lewis's defenders respond?
  • Why might an argument be rhetorically powerful even when its logical form is contested?

• Pride as the great sin

  Lewis sets pride above sensual sins as the root of the others, because it is essentially competitive and sets the self against God and neighbour. He adds that the humble person will not be thinking about humility at all, but will simply be less occupied with himself.

  • Why does Lewis call pride competitive by nature?
  • How does Lewis distinguish pride from pleasure in being praised?
  • What would humility look like in a classroom or on a team, by Lewis's description?

• Virtue as a settled character

  Lewis treats the cardinal and theological virtues not as rules but as qualities formed by repeated choices. His tennis-player example, in which a skilled player's good shots come from trained habit, makes the classical teaching of Aristotle and Aquinas plain for a radio audience.

  • What are the four cardinal virtues, and how does Lewis define prudence?
  • Why does Lewis say charity is an act of the will rather than a feeling?
  • How do small daily choices shape what kind of person someone becomes?

Context

Lewis gave the talks while Britain was at war, during the Blitz years and after, to listeners who had lost homes, family members and settled routines. The BBC's religious broadcasting department wanted a lay voice to explain the faith to a public that was nominally Christian but largely unchurched, and Lewis, already known for The Problem of Pain (1940), spoke in a plain, conversational style suited to the wireless. He also spoke to RAF stations on behalf of the chaplaincy during the same years.

Composition

James Welch, the BBC's Director of Religious Broadcasting, invited Lewis after reading The Problem of Pain. The first series, on right and wrong, aired on Wednesday evenings in August 1941; the second, What Christians Believe, in January and February 1942; the third, on Christian behaviour, in autumn 1942 in shorter ten-minute slots; and the fourth, on the doctrine of God, in 1944. Each series was published by Geoffrey Bles, as Broadcast Talks (1942), Christian Behaviour (1943) and Beyond Personality (1944). Lewis revised and expanded them for the single volume of 1952, adding a preface on the scope of the book.

Reception

Early reviews, mostly in Christian papers, praised the clarity and wit; later readers were divided, with most praise reserved for the style and most criticism for the trilemma argument. The philosopher John Beversluis criticized Lewis's apologetics at length in 1985, and Victor Reppert replied in 2003; the theologian Alister McGrath has called the trilemma one of the weaker parts of the book while ranking the book among Lewis's best. It appeared on Christianity Today's list of the books of the century, has been translated into dozens of languages, and is cited by the geneticist Francis Collins and by Charles Colson as important to their conversions.

Comparisons

• calvin-institutes

  Calvin also opens with the knowledge of God and of ourselves, but writes a full Reformed systematic theology for the learned; Lewis deliberately sets aside the questions that divided Protestants and Catholics and speaks to radio listeners in plain terms.

• the-screwtape-letters

  Written in the same war years, Screwtape dramatizes from the tempter's side the teaching on pride, humility, prayer and moods that Mere Christianity states directly in Book III.

• the-pilgrims-progress

  Bunyan presents the Christian life as a journey told in allegory; Lewis argues for the same faith by reasoning, yet his image of tin soldiers being made alive is as vivid as any of Bunyan's emblems.

• the-consolation-of-philosophy

  Boethius reasons toward God from philosophy alone in prison, without naming Christ; Lewis likewise begins from reason and the moral sense, then moves explicitly to the Incarnation. Lewis drew on Boethius for his account of God's eternity outside time in Book IV.

• pensees

  Pascal and Lewis both write apologetics for an indifferent audience and both appeal to human restlessness; Pascal works in fragments and the wager, Lewis in connected talks and the moral argument.

• the-nicomachean-ethics

  Lewis's treatment of the cardinal virtues as habits formed by repeated choices follows the classical account Aristotle gives of virtue as a settled disposition.

Quotes

For Students

A reading companion for classical Christian high school students. See the student guide.

Reading Guide

Watch for

• The preface's image of a hall with doors into rooms, which explains why Lewis avoids the questions that separate denominations.
• How Book I moves step by step from quarrels about fairness to a lawgiver behind the universe, without appealing to the Bible.
• The three alternatives in Book II, Ch. 3, and the exact sayings of Jesus Lewis bases them on.
• Lewis's claim in Book III, Ch. 8, that pride is the great sin, and how he contrasts it with vanity and with pleasure in praise.
• The images of Book IV, especially the tin soldiers, the good infection and the difference between nice people and new men.

Key terms and names

Mere Christianity

Richard Baxter's phrase, borrowed by Lewis, for the beliefs common to nearly all Christians across the churches.

Law of Human Nature

Lewis's name in Book I for the moral standard people appeal to in quarrels, which they know but do not keep.

Trilemma

Later name for Lewis's argument in Book II that Jesus must be judged a lunatic, a deceiver or the Son of God.

Cardinal virtues

Prudence, temperance, justice and fortitude, the classical virtues on which, Lewis notes, other virtues hinge.

Theological virtues

Faith, hope and charity, which Lewis treats in the last chapters of Book III as gifts directed toward God.

Begetting and making

Lewis's distinction in Book IV: a father begets a son of his own kind, while a craftsman makes something different from himself, so Christ is begotten and creatures are made.

Zoe and Bios

Greek words Lewis uses in Book IV for spiritual, eternal life from God and natural, biological life.

Seminar Questions

1. Comprehension According to Book I, what two facts about human beings does Lewis say are the foundation of all clear thinking about ourselves and the universe?
2. Comprehension What three alternatives does Lewis set out in Book II, Ch. 3, and why does he reject the view of Jesus as only a great moral teacher?
3. Comprehension What are the three parts of morality in Lewis's image of a fleet of ships?
4. Interpretation Why does Lewis begin a defence of Christianity with the Moral Law rather than with Scripture or the Church?
5. Interpretation Lewis says the humble person will not be thinking about humility. What does he mean, and how does this connect to his account of pride?
6. Interpretation In Book IV, why does Lewis say God's aim is new men rather than nice people?
7. Big Question Critics have argued that the trilemma leaves out other possibilities, such as legend. Weigh the argument and the objections: is the trilemma persuasive, and what would it need to be sound?
8. Big Question Is it possible, as Lewis attempts, to describe the faith common to all Christians without taking sides on the questions that divide them?

Faith Connections

• Romans 2:14-15 (Scripture)

  Paul says the Gentiles show the work of the law written on their hearts, their consciences bearing witness. This is the scriptural root of Lewis's Moral Law argument in Book I.

• John 8:58; Mark 2:5-7 (Scripture)

  Jesus' words "Before Abraham was, I am" and his forgiving of sins, which the scribes call blasphemy, are among the claims Lewis cites in the trilemma.

• 2 Corinthians 5:17 (Scripture)

  Paul's "new creature" is the theme of Book IV, where Lewis argues that Christ came to remake people, not merely to improve them.

• Augustine, Confessions I.1 (Church Fathers)

  Augustine's prayer that the heart is restless until it rests in God anticipates Lewis's argument from desire in the chapter on hope.

Logic and Rhetoric

Central argument: Human beings everywhere appeal to a moral law they did not invent and do not keep. A law of this kind points to a mind behind the universe that cares about right conduct. Since we have all broken that law, we stand in need of forgiveness. Christianity claims that this lawgiver came in person in Jesus, whose claims cannot be reduced to those of a moral teacher, and that through his death and life humans can be remade. Therefore the moral sense is a clue that leads, if followed, to the Christian account of God and of the self.

Rhetorical device: homely analogy. Lewis explains morality as a fleet of ships that must avoid collisions, stay seaworthy and know their destination, turning an abstract three-part scheme into a picture a radio listener can hold.

Debate: Resolved: The universal sense of right and wrong is better explained by a moral lawgiver than by evolution or social convention.

Writing Prompts

Essay: Choose one argument from Mere Christianity (the Moral Law, the trilemma, or the argument from desire), state it fairly, present the strongest objection, and argue whether Lewis's argument survives it.

Comparison with Institutes of the Christian Religion: Calvin and Lewis both explain the Christian faith to readers of their time. Compare how each begins, whom each addresses and what each leaves out, and argue what is gained and lost by Lewis's decision to describe only the faith common to all churches.

Medical Lens

The book is moral theology, not medicine, but two passages engage psychiatry directly. In Book III, chapter 4, Morality and Psychoanalysis, Lewis accepts that psychoanalysis may cure abnormal feelings and fears, and distinguishes the psychological raw material a person is given, including irrational fears and perverse impulses, from the moral choices made with it; he argues that God judges the choice rather than the material, a position that has been read alongside later separations of symptom from character. In Book IV he returns to temperament, contrasting a person with a sour, nervous disposition who struggles toward goodness with an easy-natured person who has never been tested. The trilemma in Book II relies on lunacy as one of its alternatives, and some critics have objected that a person with grandiose delusions may also teach wisely; this is a debate about the argument, not a clinical claim by Lewis. These links are interpretive readings.

• Book III, Ch. 4, "Morality and Psychoanalysis"

  Lewis separates psychoanalytic treatment of abnormal fears and impulses from the moral choices a patient makes, and says the treatment of the raw material is a medical matter.

  Psychology Unconscious Neurosis Anxiety
• Book II, Ch. 3, "The Shocking Alternative"

  The trilemma offers lunacy as one explanation for Jesus' claims, using the image of a man who thinks he is a poached egg.

  Madness Psychosis
• Book IV, Ch. 10, "Nice People or New Men"

  Lewis contrasts inherited temperament and upbringing with moral effort, arguing that a person with a difficult nervous constitution may be further along than an easy-tempered one.

  Mind Body Neurosis Anxiety

Creative Prompts

• Essay

  Restate Lewis's Moral Law argument from Book I in five numbered steps, then write a reply from a thoughtful skeptic and a rejoinder in Lewis's style.

• Dialogue

  Write a conversation between Lewis and one of the trilemma's critics, such as a New Testament scholar who doubts that Jesus' sayings are reported word for word, letting each make his strongest case.

• Adaptation

  Write and record a ten-minute radio talk, in Lewis's plain broadcast manner, explaining one virtue from Book III to listeners your own age.

• Classroom

  Make a chart of the images Lewis uses to explain doctrine (the hall and rooms, the fleet of ships, the occupied territory, the tin soldiers, the good infection) and state the point of each.

Further Reading

• The Abolition of Man, C. S. Lewis

  Lewis's 1943 lectures on the objective moral law, which he calls the Tao.

• The Problem of Pain, C. S. Lewis

  The 1940 book that led the BBC to invite Lewis to broadcast.

• Surprised by Joy, C. S. Lewis

  Lewis's account of his own path from unbelief to faith.

• C. S. Lewis's Mere Christianity: A Biography, George M. Marsden

  History of the broadcasts, the book and its reception.

• C. S. Lewis: A Life, Alister McGrath

• C. S. Lewis and the Search for Rational Religion, John Beversluis

  A philosopher's critical assessment of Lewis's apologetic arguments.