Is Christianity rational? Revisiting Mere Christianity.

It may come as a surprise that the all-time best-selling work of apologetics was written not by one of the great Christian philosophers or theologians, or even by a popular evangelist, but instead by a humble English professor of literature. We know him as C. S. Lewis. His book Mere Christianity may bear a modest title, but its commercial success has been anything but modest. Though first published as a single volume in 1952, to this day Mere Christianity regularly outsells all other books in its category, even new releases.

For the cause of apologetics Lewis appears heaven-sent. Who better to tell the story of Christian redemption than a natural-born storyteller? Lewis had a gift for grounding abstruse ideas, often clothing them in analogies to common experience. How many writers could have produced the Chronicles of Narnia, a septet of best-selling children's books recasting Christian theology and morality as richly textured allegorical fantasies? What's more, as an intellectual and an erstwhile atheist-turned-Christian at the relatively mature age of thirty-two, Lewis was able to address from personal experience the common stumbling blocks for non-believers and lay out the very case for Christianity that had persuaded him.

Scholars tell us that religion (or irreligion) is more often a matter of the heart than of the head; this is why religious beliefs are usually not amenable to rational argument. Yet Lewis, to his credit, isn't content to rest with the "convictions" of the heart, which can be dangerously wayward without the guiding rudder of reason. Instead, he takes a thoroughly rationalist approach to religion, arguing that "the weight of the evidence" for mere Christianity--Christianity's core doctrines--is on the side of the Christian. A half-century after the initial publication of Mere Christianity, we may ask: is its argument as convincing as it is popular?

The centerpiece of Lewis' case for Christianity is his case for Christ. This isn't just an argument that Jesus of Nazareth existed but that, as in John 1:14, he was God incarnate, the word made flesh. Lewis berates atheists and agnostics who seek to accommodate Jesus within their secular worldview as a great but merely human moral teacher and role model. Jesus himself claimed to be God, so if he wasn't divine he could scarcely be a role model. "He would either be a lunatic--on a level with the man who says he is a poached egg--or else he would be the Devil of Hell" for promulgating such a diabolical lie. Hence, as Lewis sees it, skeptics are confronted by an awkward trilemma: liar, lunatic, or lord?

Unsurprisingly, matters aren't so simple. It can be argued that the three alternatives of the trilemma aren't exhaustive. Another possibility is that Jesus' alleged claims to divinity aren't historical. Even (liberal) Christian theologians argue that Jesus never claimed to be God incarnate.

Gospel evidence for such a claim is mixed at best. While Jesus' sayings intimate that he saw himself as bearing some special relationship to God, they often presuppose that Jesus and God aren't one and the same being. For example, when Jesus, anticipating his crucifixion, bids his disciples farewell in John 14:28-31, he draws explicit contrasts between himself and "the Father":

  If you loved me, you would have rejoiced,
   because I go to the Father; for the Father is
   greater than I... but I do as the Father has
   commanded me, so that the world may
   know that I love the Father. [Emphasis
   added]

Such passages suggest that the divinity of Jesus is an ex post facto, doctrinal superimposition onto historical reality rather than an extraction from it.

Even if Jesus did claim to be God in the biblical accounts of his ministry, the evidence for the historicity of such accounts is scarcely compelling by modern scientific standards. Even most conservative biblical scholars concede that the authors of the gospels weren't eyewitnesses to Jesus' ministry but wrote second-hand accounts at least thirty to forty years after Jesus' death. Moreover, the earliest available accounts of Jesus' ministry aren't originals but copies of copies, with each transcription being vulnerable to human error and editorial alteration.

Once the gospels' layers of possible inauthenticity are peeled away, we are left with a core text much too meager to serve as an adequate evidential basis for the grand claims of orthodox Christology. Thus Lewis' trilemma seems egregiously incomplete. What can the skeptic make of Jesus insofar as he is said to have claimed divinity? Not just liar, lunatic, or Lord. Jesus thus portrayed could also be the stuff of legend.

As long as there has been religion, believers have accepted that they are in need of atonement--the achievement of "at-onement" with the divine. In the Judeo-Christian tradition, the Old Testament is filled with stories of atoning animal sacrifice. Jews have since dispensed with the notion that the sacrifice of life is necessary for atonement. Orthodox Christians, however, continue to believe with Hebrews 9:22 that "without the shedding of [Christ's] blood, there is no forgiveness of sins."

Mere Christianity's chapter on the Christian doctrine of atonement, "The Perfect Penitent," depicts perfectly the penance Jesus has done for the human race. According to Lewis the crux of the Christian doctrine of atonement is that "Christ's death has somehow put us right with God and given us a fresh start."

Precisely how it does so is a matter of controversy. While allowing for multiple satisfactory models of atonement, Lewis makes a pitch for his own preference, which might be dubbed "the debt-satisfaction model." Skeptics ask what the point of punishing an innocent person for the wrongdoing of others could be. "None at all," Lewis replies, "if you are thinking of punishment in the police-court sense." But "if you think of a debt, there is plenty of point in a person who has some assets paying it on behalf of someone who has not."

Certainly, the notion that one person can pay off the debts of another makes sense. What arguably doesn't make sense is the claim that this notion serves as an adequate model for understanding specifically how Jesus' death could atone for the sins of humankind. To suppose that we inflict anything like financial damages on God when we do wrong strains credulity. But perpetrated wrongs that aren't financial in nature cannot be atoned for by a third party, no matter how morally pure that person may be. Indeed, in the legal systems of democracies, the notion that one person can suffer the punishment, even voluntarily, for the criminal offense of another is so absurd as to be beyond discussion.

It is understandable that Lewis devotes nearly a third of Mere Christianity to Christian morality, as religion and ethics are nearly inseparable in the popular imagination. In keeping with this widespread conception, Lewis believes the surest way to gain moral knowledge is "to find out what Christianity says." In his view the ultimate ground of right and wrong is agreement or disagreement with the Bible or Christian tradition.

Yet such an ultimate moral standard is implausible. The wrongness of rape and theft, for example, doesn't depend on the Bible's or Christian tradition's condemnation of them. Moreover, some of the moral prescriptions set forth in the Bible--such as the command of Leviticus 20:13 that sodomites be put to death--are repudiated by the vast majority of Christians. These Christians reverse Lewis' order of justification, using extra-religious beliefs as a touchstone for the soundness of biblical commands rather than vice versa.

Lewis' nonreligious moral arguments tend to be no more cogent. In his chapter on "Sexual Morality," for example, he appeals to biological purpose in order to establish the immorality of extramarital sex: "The biological purpose of sex is children, just as the biological purpose of eating is to repair the body." But why think biological purpose is morally normative? The biological purpose of a woman's hips is to accommodate a growing fetus, yet she commits no moral transgression when she employs them for the purpose of holding up her pants.

The engaging prose and charming analogies of Mere Christianity present a shimmering exterior. But scratch it and it quickly crumbles. All too often, Lewis' arguments oversimplify and fail to come to grips with the fundamental doubts of the nonbeliever. What, then, accounts for the enduring popularity of Mere Christianity? It is hard to escape the conclusion that Lewis is preaching to a very receptive choir.

Andrew Johnson received a B.A. in philosophy from the University of Notre Dame in 1990 and a Ph.D. from the University of North Carolina at Chapel Hill in 2001. He currently lives in largely secular Germany, and can be reached at [e-mail]