Download a PDF to print or study offline.

Study Guide
Cite This Study Guide

How to Cite This Study Guide

quotation mark graphic


Course Hero. "Mere Christianity Study Guide." Course Hero. 29 Nov. 2017. Web. 17 Nov. 2018. <>.

In text

(Course Hero)



Course Hero. (2017, November 29). Mere Christianity Study Guide. In Course Hero. Retrieved November 17, 2018, from

In text

(Course Hero, 2017)



Course Hero. "Mere Christianity Study Guide." November 29, 2017. Accessed November 17, 2018.


Course Hero, "Mere Christianity Study Guide," November 29, 2017, accessed November 17, 2018,

Mere Christianity | Summary



Book 1: Right and Wrong as a Clue to the Meaning of the Universe

Lewis argues there is a Law of Human Nature that each human experiences as the internal sense that he ought to do what is right and not what is wrong. This is a real law, universal and inborn, and underlying it is a universal standard of morality that allows us to assess good and bad. Unlike the rest of nature, the Law of Human Nature is prescriptive, rather than descriptive, and unlike the law of gravity people are free to disobey the law and often do. The Law's concern, not with what is but with what ought to be, points to the existence of a reality beyond the facts of the observable universe. That the Law expresses a preference for human behavior rather than describes a physical, chemical, or biological process indicates the mindlike quality of this other reality.

Were there a God, He would not reveal Himself to us through science, or observable facts, but in some other way. Lewis thinks the Law of Human Nature is evidence for an all-powerful, all-good God whose intense concern with human morality does not impede upon human free will. Humanity is in a dire state, however, because we always break the Law of Human Nature. Thus we put ourselves at odds with the one who made the Law—God. The point at which we realize this, Lewis says, is the point at which "Christianity begins to talk."

Book 2: What Christians Believe

Having made a case for God's existence, Lewis refutes dualism and pantheism as belief systems. When he was an atheist, he thought the world being unjust was proof God didn't exist. Lewis now refutes this argument, claiming justice exists in the world because we can conceive of its opposite.

Lewis explains God's perfect creation went wrong and evil. That evil does not exist on its own but is a perversion of goodness. Evil is embodied in the figure of the devil, and it is he who rebelled against God and set off the universal civil war now taking place. Humankind has unfortunately gone to the rebel side, thinking it can do just fine without God. Christ's incarnation, predicted by the mythologies of the world, was God, "the rightful king," coming to Earth "in disguise ... calling us all to take part in a great campaign of sabotage." Humanity must lay down its rebel arms and return to God's side to fight Satan.

We must take Christ's claims to divinity seriously, for the only alternatives are a lunatic or evil, and we must each take possession of the salvation He brought to the world through His death and resurrection. We invite the new life Christ brought, the spiritual life of God, to enter us through baptism, belief, and participation in Holy Communion.

Book 3: Christian Behavior

We start out on the Christian path through our attempt to practice Christian morality perfectly. Morality consists of seven virtues: prudence, temperance, fortitude, justice, faith, hope, and charity (or love). We are to practice these virtues even if we don't feel like it by acting "as if," and this practice over time shapes our character to God's liking.

Our attempts to be perfectly moral are destined to result in failure. This failure is necessary to bring us to the point where we surrender our ego and become humble enough to ask for God's help. At this point we put all our trust in Christ. This is the point at which true faith arises, and it is this faith that we must have before Christ can do His work in us.

Book 4: Beyond Personality: Or First Steps in the Doctrine of the Trinity

Lewis explains the theology behind the Atonement, the three-person God, and the process of transformation a Christian undergoes.

In God's view humanity is a single organism. When Christ incarnated into man, He put His God nature into the human organism, making this spiritual life (Zoe) available to each human. This was the function of the Atonement. When we put our faith in Christ, we begin the process whereby our biological life (Bios) is transformed into the spiritual life (Zoe) of God. This process is painful, but the rewards are great. Not only do we experience peace and happiness, we are made "begotten" in the same way Christ is begotten of the Father—filled with the same kind of life as Him.

We become "little Christs," and this transformation is Christianity's goal. This transformation is the next step of evolution, whereby life on Earth reaches a perfection beyond that of ordinary man. These "new men" are already on Earth, having taken part in this transformation that is not complete in this lifetime. Now is our chance to join them, to take the next step, transcending history and nature. Now is the time for us to reconcile with God, for it will one day be too late.

Cite This Study Guide

information icon Have study documents to share about Mere Christianity? Upload them to earn free Course Hero access!