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Mere Christianity | Study Guide

C.S. Lewis

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Mere Christianity | The Christianity of Mere Christianity


The Christianity of Mere Christianity


Mere Christianity is a work of Christian apologia. Apologia is a Greek word meaning "a speech in defense." Far from being apologies, in the common modern sense of the word, writers of apologia use rational arguments to defend and explain their beliefs and actions. One of the best known and earliest apologetic works is Plato's "Apology." In this work Plato recounts the defense the philosopher Socrates gave before a court that wanted to sentence him to death for "corrupting the youth" of Athens with his teachings. The first works of Christian apologetics were written during the religion's early days. The genre has been part of Christian theology since then. Famous Christian apologists include St. Paul, St. Thomas Aquinas, Kierkegaard, Paul Tillich—and C.S. Lewis.

The ultimate goal of any apologia is to convince the audience to accept the point of view presented. The goal of Christian apologia is to induce skeptics to convert. The four functions of apologia attempt to achieve this result. First the apologist uses reason and evidence from philosophy, science, history, or other disciplines to argue for the acceptance of Christianity. Lewis attends to this function of vindication, or proof, in Book 1 of Mere Christianity. Second the apologist presents a defense in order to gain credibility. This is done by addressing the audience's objections, misrepresentations, and questions about Christianity. Lewis does this throughout the text. The third function is refutation, or offense. Through rational analysis, the apologist reveals the inadequacy or incorrectness of opposing positions. Lewis undertakes this function when he refutes atheism, pantheism, and dualism. The fourth function is persuasion. It consists of convincing the audience not only of the truth of Christianity but also that they ought to apply it in their own lives. Lewis's arguments for the authority of the scriptures, his continual insistence on the rewards of being Christian, and his warnings about what will befall those who do not choose Christianity all work toward the function of persuasion.

Lewis had his own ideas about apologia, which he put into practice as he composed the radio scripts that would later become Mere Christianity. In Lewis's view, the successful apologist understood and catered to the audience's specific assumptions, inclinations, and aptitudes. Lewis knew his BBC audience would only be alienated by the usual digressive, complex, ambiguous theological arguments. They would also not understand the specialized vocabulary. Likewise he understood they were not interested in subtleties or nuances, nor in an extensive deconstruction of the opposing arguments. Lewis felt his audience would respond to a tone that was casual, humorous, and confident. Simple analogies would allow him to present complex ideas without resorting to long digressions and technical vocabulary. A style that was conversational, casual, and vernacular would establish trust and maintain attention. He focused on these rhetorical aspects rather than on presenting airtight, irrefutable arguments or an overly complex picture. His approach was successful: the BBC loved it, the British people loved it, and half a century later Mere Christianity has become the standard of modern Christian apologia.


Although the presentation is fresh, the ideas in Mere Christianity are not Lewis's own. He drew them from some of the foremost thinkers of ancient and modern times. A consideration of some (but by no means all) of the great thinkers who shaped Lewis's views will help the reader appreciate Lewis's genius for style and synthesis. It will also help them recognize his familiarity with, and foundation in, the long traditions of philosophical discourse and apologetics.

Lewis took his title from the work of Richard Baxter. Baxter was an English Protestant clergyman and prolific writer of apologia who lived from 1615–91. In 1680 Baxter wrote, "I am a Christian, a Meer Christian ... But must you know what Sect or Party I am of? ... I am of that Party which is so against Parties." Lewis agreed with many of Baxter's ideas, such as the belief that Christians must unify rather than split into denominations. And he agreed that justification for salvation consisted of the earnest practice of faith and good works.

In Mere Christianity Lewis promotes virtue-based normative ethics. Normative ethics are concerned with finding standards or criteria for judging right and wrong. Virtue ethics are a subclass of normative ethics that holds that morality should not be a system of rules but a system of virtues. The practice of these virtues develops good character. This system arose in ancient Greece and is found in the works of Plato and Aristotle, likely the "old writers" Lewis references when discussing the Law of Nature in Book 1. In fact the four cardinal virtues Lewis discusses in Book 2 are found in the writings of Plato and are often called "Platonic virtues."

In Chapter 2, Book 1 Lewis describes the reasoning by which he finally saw through the argument he had been using to defend his atheism. Lewis felt God couldn't exist because the world was unjust. However, he realized justice must exist because he could conceive of its opposite. Since there was justice in the world, Lewis lost his rational claim to atheism. This type of argument is known as an ontological argument. It deals with the nature of reality and functions on the assumption anything the human mind can conceive of has a parallel in reality. It was first used in the 11th century by Anselm of Canterbury who argued God's existence based on humanity's ability to conceive of God.

Lewis counted St. Augustine's Confessions among the books that most influenced him as a Christian. His adoption of Augustine's thought is evident in Mere Christianity. Augustine was preoccupied with the problem of evil in a world entirely created by a good God. Augustine used logic to conclude evil was not created by God, nor is it a thing. Now faced with the problem of defining evil, Augustine wrote, "Evil has no positive nature; but the loss of good has received the name 'evil.'" Lewis argues the same in Mere Christianity when he states, "Evil is a parasite, not an original thing." He echoes Augustine in equating existence with goodness and claiming the impossibility of choosing evil. Lewis also drew directly on Augustine in developing a number of other ideas presented in Mere Christianity. Among them are the idea of the Holy Spirit arising out of the relationship between the Father and the Son; the distinction between making and begetting; and the dichotomy of spiritual life (Zoe) replacing biological life (Bios) in the Christian.

Core Christian Concepts

  • Original Sin and the Fall: While Lewis never uses these terms, nor references the biblical narratives underlying the doctrines, these ideas are key in Mere Christianity. Long ago people decided they could achieve their own happiness, and so they turned from God and joined forces with Satan. Humanity's sinfulness is a result of this turning away. It is revealed in our constant failure to behave morally. We can be cleansed of sin and reconciled with God when we choose to repent and put our trust in Christ.
  • Nonexistence of Evil: Evil is not a thing unto itself but is merely the perversion of the good with no separate existence of its own. This is why the Christian embodiment of evil, Satan or the devil, is a fallen angel who was once good but who fell away from God because of his pride.
  • Free Will: God gave humans free will, which makes possible real happiness but which also caused us to turn away from Him. Our free will occasioned our separation from Him, and we must use it to choose to return to Him. God can see all of time at once, but we experience only the present while the future remains hidden from our view. Because of this His foreknowledge of our choices doesn't conflict with us making free choice.
  • Morality: God is intensely interested in right and wrong and in the quality of our true character. Evidence of this can be seen in the Law of Human Nature, which God puts into every person. By attempting to practice perfectly the seven Christian virtues, we eventually become humbled enough to repent. We turn ourselves over to Christ, and the process of salvation gets underway. The end result (not in this lifetime) is that we become like Christ, transcending the need for morality altogether.
  • The Atonement: Humanity needed help reconciling with God but was unable to undertake the perfect repentance (acknowledgment of error and surrender) required. The Atonement is what God did to help humanity achieve reconciliation. God incarnated as the person of Christ and entered into history to pay humanity's debt to God by His life, suffering, death, and resurrection. We achieve salvation when we claim the Atonement for ourselves through our individual repentance.
  • Baptism, Belief, Holy Communion: After we have repented, we grow in Christ through our baptism, our belief, and our participation in Holy Communion, or the Lord's Supper. Each denomination has its own theories and practices about these, but they all agree on their importance on the Christian path.
  • The Second Coming: God will return to the world, just as Christ promised, in His full, unveiled goodness. The world will end and we will either be horrified or full of love as this happens, depending on whether or not we have repented and accepted salvation. History continues for the moment to give humankind time to choose repentance before the Second Coming, when it will be too late to choose the side of God.
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