S. Lewis's argument for the truth of Christianity, adapted from radio talks broadcast on the BBC between 1941 and 1944. Lewis structures the case in four parts: first, an argument from the universality of moral law to the existence of a moral lawgiver; second, an account of Christian theology and the famous Liar, Lunatic, or Lord trilemma about the identity of Jesus; third, an examination of Christian ethics including the cardinal and theological virtues, pride as the root sin, and the mechanics of faith; and fourth, a plain-language treatment of the Trinity, the Incarnation, and what Lewis calls the "new men" — humans being remade from within by Christ.
The prose is conversational throughout, aimed at a sceptical civilian audience rather than academic theologians.
If we find ourselves with a desire that nothing in this world can satisfy, the most probable explanation is that we were made for another world.
p. 136 · Book III, Chapter 10 "Hope"
First lines
Every one has heard people quarrelling. Sometimes it sounds funny and sometimes it sounds merely unpleasant; but however it sounds, I believe we can learn something very important from listening to the kind of things they say. They say things like this: "How'd you like it if anyone did the same to you?" — "That's my seat, I was there first" — "Leave him alone, he isn't doing you any harm" — "Why should you shove in first?" — "Give me a bit of your orange, I gave you a bit of mine."
Contents
Book I: Right and Wrong as a Clue to the Meaning of the Universe
1. The Law of Human Nature
2. Some Objections
3. The Reality of the Law
4. What Lies Behind the Law
5. We Have Cause to Be Uneasy
Book II: What Christians Believe
1. The Rival Conceptions of God
2. The Invasion
3. The Shocking Alternative
4. The Perfect Penitent
5. The Practical Conclusion
Book III: Christian Behaviour
1. The Three Parts of Morality
2. The "Cardinal Virtues"
3. Social Morality
4. Morality and Psychoanalysis
5. Sexual Morality
6. Christian Marriage
7. Forgiveness
8. The Great Sin
9. Charity
10. Hope
11. Faith
12. Faith (continued)
Book IV: Beyond Personality: Or First Steps in the Doctrine of the Trinity
1. Making and Begetting
2. The Three-Personal God
3. Time and Beyond Time
4. Good Infection
5. The Obstinate Toy Soldiers
6. Two Notes
7. Let's Pretend
8. Is Christianity Hard or Easy?
9. Counting the Cost
10. Nice People or New Men
11. The New Men
Reception
Mere Christianity was initially received with broad enthusiasm in Christian publications; The Times Literary Supplement praised Lewis's "quite unique power" of making theology interesting. Its overall reception across decades is mixed: the directness and accessibility of the prose are consistently praised across traditions, while the central "Liar, Lunatic, or Lord" trilemma has drawn sustained criticism from theologians and biblical scholars, including the Lewis biographer Alister McGrath, who called it the book's "most obvious concern" and argued it is unsupported by modern biblical criticism. The biographer Margaret Patterson Hannay described it as Lewis's "most popular and most disparaged" work. It has been translated into more than thirty languages and is routinely cited by public figures — including Chuck Colson and Francis Collins — as a factor in their conversion to Christianity. It consistently appears in lists of recommended Christian apologetics.
Frequently asked
What is Mere Christianity about?
It is C.S. Lewis's case for the truth of Christianity in four parts: an argument from universal moral law to the existence of God; a defence of Christian theology including the Liar, Lunatic, or Lord trilemma; an account of Christian ethics covering pride, forgiveness, faith, and the cardinal virtues; and a plain-language treatment of the Trinity and the transformation of human nature.
Where did the book come from?
Lewis gave a series of BBC radio talks between 1941 and 1944, reaching a wartime civilian audience. The talks were published separately as three short books and then combined with revisions into Mere Christianity in 1952. Lewis wrote for an audience of ordinary sceptics, not academic theologians, and kept the language deliberately plain.
What is the Liar, Lunatic, or Lord trilemma?
Lewis argues that Jesus claimed to be God. He then reasons that a person making that claim is either telling the truth (Lord), deliberately deceiving people (Liar), or sincerely but wrongly believes it (Lunatic). Lewis argues the evidence of Jesus's character rules out the second and third options. The trilemma has been widely discussed and criticised; the main objection is that it omits the possibility that the Gospel accounts of those claims are historically inaccurate.