C.S. Lewis was a man of many parts. His novels, allegories, and children’s books achieved enormous popularity. He excelled as a spiritual writer and had some standing as a poet. In the academic field he was competent in philosophy, a master of the Greek and Latin classics, and outstanding as a literary critic.

But he is best known today as an apologist”probably the most successful Christian apologist of the twentieth century. Forty and more years after his death, his influence remains unabated. His works are read by Protestants and Catholics with equal relish. Enough books have been written on Lewis to fill several shelves of a bookcase.

Although Lewis’ achievements in apologetics have been generally acclaimed, he is not without his critics. In his lifetime he had to meet objections from his fellow Anglican W. Norman Pittinger and the Catholic philosopher Elizabeth Anscombe. In 1985, twenty-two years after his death, a book-length refutation of Lewis’ entire apologetical project was published by the philosopher John Beversluis. The various criticisms, however, reflect the presuppositions of their authors, which are not self-evidently true. One problem stems from the notion of “mere Christianity,” which Lewis selected as the position to be defended. It is easy to object that there is no such thing as “mere Christianity” and that major differences, such as those between Protestants and Catholics, cannot be papered over. Aware of the objection, Lewis compared mere Christianity to a hall through which one finds one’s way into the bedrooms of a house. The hall is not a place where anyone wishes to stay, but it is a place from which one can gain access to one or another of the rooms, recognizing that those in neighboring rooms are one’s housemates. By “mere Christianity” Lewis means the common fund of doctrines and practices enshrined in Scripture and the early creeds, which are foundational for most Christian churches.

Lewis developed his apologetic for Christianity in three stages. First, he set out to establish the existence of God on grounds that are chiefly philosophical. Then he sought to demonstrate that God has preeminently revealed himself in Christ and in the Christian religion. Finally, he defended theism and Christianity against common objections, such as the problem of evil.

Against the prevalent agnosticism of his day and ours, Lewis believed it was possible to demonstrate the existence of God, at least in the sense of making God’s existence vastly more likely than his non-existence. He was aware of the ontological argument, usually identified with Anselm and Descartes, and the cosmological arguments classically set forth by Thomas Aquinas. As for the ontological argument, which deduced God’s existence from the very concept of a Necessary Being, he said in a letter to his brother Warren that the argument would not be valid unless one first established that the idea of Necessary Being from which it begins is objectively grounded and is not a mere fabrication of our minds. He did not reject the cosmological arguments from the facts of change, causality, and contingency, but he confessed in a letter to his friend Bede Griffiths that they were ineffective for him personally. But his own favorite proofs are those from morality, from reason, and from desire.

The argument from morality, rather fully set forth in Lewis’ radio talks, The Case for Christianity , begins with the assertion that we are unconditionally bound to do good and avoid evil. All normal human beings spontaneously judge that certain actions are wrong and ought not to be done. They know they ought to be honest, truthful, temperate, just, and loving toward others”and that they are forbidden to commit theft, perjury, adultery, murder, and the like. About the details of the moral code there can be disagreements, but not about its obligatory character. The question is where the obligation comes from. According to the classical tradition of Christian theology, stemming from St. Paul, the obligation comes from God who, so to speak, writes His law upon the human heart, so that even people to whom the positive moral law has not been proclaimed have an inborn sense of what is commanded or prohibited. When they do wrong, they suffer from a bad conscience and realize that they deserve to be punished.

Lewis takes up and refutes the most common objections to this argument. He gives solid reasons for denying that the sense of moral obligation could arise from a herd instinct, from social convention, or from a Freudian superego. The only adequate explanation, he maintains, is that we are subject to a higher will, to which we are accountable for the use we make of our freedom. Addressing a popular audience, Lewis does not enter into every technicality or refute every difficulty, but he puts forth the essentials in simple and persuasive language.

Lewis’ second favorite proof, the argument from reason, appears in his book Miracles . A certain kind of naturalism, he observes, characterizes rational thinking as a mere product of nervous reflexes, instincts, and habits. Lewis replies that physical or psychological conditioning cannot explain our power to make judgments about truth and error. We are conscious that our judgments are determined not by subrational forces but by reality as it impinges on our minds. The power to reach understanding through rational explanations is evidence of an affinity between the mind and reality. It is explicable only if there is an aboriginal mind that accounts for both intelligence and intelligibility.

Lewis’ sketchy presentation of this argument leaves further work to be done. Having an ancestry that goes all the way back through Plato to Anaxagoras, it resembles the argument for the existence of God proposed in highly technical terms by Bernard Lonergan and popularized in several apologetical works of Hugo Meynell. For all these authors the wonderful correspondence between reason and reality implies that reality is imbued with an order that stems from a creative Mind. Lewis’ focus is not so much on the intelligibility of the world as on the mind’s capacity for truth, which in his opinion cannot be explained by natural selection but only by an intelligent Creator.

Lewis’ third argument is taken from the natural desire for union with God. The idea that the human soul is naturally drawn to such a blessed union is pervasive in the Christian tradition. Augustine put it in classic form when he exclaimed in the Confessions : “You have made us for yourself, O God, and our hearts cannot find rest until they rest in you.” This desire for God was not proposed in the form of a proof, it would seem, until the twentieth century. Influenced by the Belgian Jesuit Joseph Maréchal, the French Jesuit Henri de Lubac and the German Jesuit Karl Rahner made it their primary proof for the existence of God. Lewis was apparently unfamiliar with these continental authors, but he may well have found the makings of his own argument in the Anglican theologian Richard Hooker.

The argument unfolds in several steps. First, it must be established that all human beings have by nature a desire for something that transcends the whole of creation. According to Lewis, it is a secret desire that needs to be discovered, but one that each human being can discern by careful introspection. No earthly happiness can fully satisfy our hearts. The crux of the argument is the premise that no natural desire can be in vain. This proposition was accepted as self-evident by Aristotle and the entire Scholastic tradition, which subscribed to a teleological view of nature, but is rejected by empiricists, who protest that we lack sufficient materials to make this induction. Without delaying on the objection, Lewis draws the conclusion that God must exist, for otherwise the desire would be in vain and would have no attainable object.

In his autobiography, Surprised by Joy , Lewis designates this longing by the German name Sehnsucht and analyzes it in highly experiential terms. This unsatisfied desire, he remarks, is more desirable than any earthly satisfaction. For a while he so enjoyed the desire, he confesses, that he almost lost sight of the divine Object, but he overcame this subjectivism with the help of the idealist philosopher Samuel Alexander. In the end he came to realize that it was less a case of his pursuing the Object than of the Object’s pursuing him.

Lewis was convinced that his arguments, especially when taken in convergence, established the existence of a personal God who is the source of morality, rationality, and spiritual joy. God stands above and beyond the whole of creation as its eternal ground. This idea of God, he claims, is far more plausible than pantheism, which so intermingles God and the world that God could not exist unless it did. After having dallied for a while with a kind of Hegelian pantheism, Lewis came to realize that a God indistinct from the world could not be unconditionally true and good. The proofs we have summarized establish the existence of a God who is untouched by evil.

Lewis does not extensively discuss non-Christian religions. Once the option for religion has been made, the only serious alternatives are pantheism and monotheism. Hinduism, which represents pantheism at its best, fails to satisfy Lewis. Buddhism he writes off rather casually as a Hindu heresy. A choice must therefore be made among the great theistic religions”Judaism, Islam, and Christianity”and if one can show that Christianity is divinely revealed, then it must be the choice. Other religions can be true only to the extent that they are compatible with it. Christians are not bound to regard other faiths as false except at those points where they conflict with Christian faith.

To establish the fact of Christian revelation, Lewis pursues two lines of argument. His first approach is from the claims of Christ. In a trilemma borrowed from G.K. Chesterton he asserts that anyone who claims to be God must be a lunatic, a liar, or, in fact, God; since Jesus, who made divine claims, was neither a liar nor a madman, therefore he was God. Lewis knows, of course, that the argument is not that simple. Nearly everyone will concede that Jesus was neither a lunatic nor a deceiver, but Lewis wants to make the adversaries explain why, after asserting that Jesus was sane and good, they deny his divinity.

The main difficulty, of course, is to establish that Jesus in fact claimed to be God. He may not have said bluntly, “I am God,” but according to the Gospels he spoke of himself as Son in a unique and transcendent sense. In a number of sayings Jesus clearly implies that the Son preexisted with the Father, is equal to the Father, and will return in glory at the end of time to judge all nations. Jesus also claims to forgive sins in his own name, an act admittedly reserved to God alone.

Lewis’ second argument for the divinity of Christ is from miracles, a subject on which he wrote one of his most important apologetical books. The book is a very successful answer to authors such as Hume, who denied that historical accounts of physical miracles could be credible. Lewis in a long discussion of the laws of nature shows that such laws, far from precluding miracles, are necessary conditions for their possibility. If there were no regular laws of nature, miracles could not be recognized as exceptions and would lose their function as divine signs. Miracles are possible provided that such laws exist and provided also that God is not absolutely bound by the laws He has established. True, it would be unreasonable for God to suspend laws of nature in an arbitrary way, but it would make sense for Him to suspend them on occasion for adequate reasons such as the manifestation of the new order of salvation.

If miracles were haphazard events, reports about them might not be credible. But the biblical miracles, generally speaking, fall into a meaningful pattern, exhibiting the beneficent designs of God. All the biblical miracles lead up to, or attest to, the Incarnation, which Lewis describes as “the great miracle.” Jesus’ mastery over life and death and over the powers of nature is convincing evidence of his divinity.

After a survey of the miracles of the public life, Lewis devotes a chapter to the resurrection. As a sign and anticipation of the final Kingdom, the resurrection is eminently meaningful. All efforts to explain it away as hallucination or fabrication fall to the ground.

Lewis is well aware that his arguments from the claims of Jesus and from the biblical miracles presuppose the general reliabilty of the Gospel accounts. Although Lewis does not claim to be a specialist in New Testament criticism, he maintains that he is well qualified as a literary critic to distinguish between history, legend, and myth. The Gospels clearly belong to the genre of history. The skepticism of radical New Testament critics like Bultmann, he contends, has its roots in their philosophical commitments, not in the character of the texts.

Against modern critics who treat the Fourth Gospel as unhistorical, Lewis boldly counters: “My judgment as a literary critic . . . constrains me to think it at least as close to the facts as Boswell’s Johnson .” But he also says: “I could never see how one escaped the dilemma aut deus aut malus homo by confining oneself to the Synoptics.”

The principal reason for Lewis’ adherence to atheism as a young man was his conviction that there was too much evil and suffering in the world for it to be the work of a loving and all-powerful God. In the opening pages of The Problem of Pain he poses the problem of evil in starkest terms. But he argues that the experience of evil as a problem rests upon a prior awareness that there exists a higher order of justice. This inbuilt sense of what ought to be cannot be explained except as having been implanted in our hearts by a divine power.

Lewis does not pretend to give a rational solution to the problem of evil. The Book of Job reminds us that with our finite minds we cannot provide a theoretical solution. But for apologetics it suffices to show that the fact of evil does not positively disprove the existence of the biblical God. Lewis begins by refuting metaphysical dualism, which would hold that good and evil are equally primordial. From Augustine he takes the insight that evil is a parasite, not an original reality. All the things that enable a bad person to be bad are in themselves good things. An evil deity, if it existed, would have existence, intelligence, and will, and to that extent be good. Evil, therefore, is the perversion of a goodness prior to itself.

In a universe of finite things, Lewis maintains, some degree of evil is normal. Often enough, one entity achieves its proper good at the expense of another. The lion gets the meat it needs for its diet at the expense of the sheep. Does the sheep suffer? It certainly has sensations, but of a sheep’s consciousness we know nothing. What appears to be animal suffering may not be suffering in any real sense. We must beware of falling into the “pathetic fallacy.”

Evil in the sphere of human life admits of various explanations. In a social order, it is reasonable to suppose that just as human beings benefit from one another’s achievements, they will have to suffer from the mistakes and failures of others. But such suffering, endured with patience, can make for spiritual growth. It is good that we may attain some degree of happiness on earth. The impossibility of attaining complete happiness here below is good in the sense that it helps us to keep our hopes concentrated on God and the life to come.

God could of course prevent any given mishap by a miracle. But miracles must in the nature of the case be rare. Frequent interventions from on high would destroy the order of nature and make it impossible for us to act meaningfully, since the consequences of our actions would be unforeseeable. We could not build or use machinery unless we could predict how it would function.

The evil in the world is vastly increased by human sin. The possibility of sin proves nothing against God’s goodness, because unless it were possible, God could not obtain the free and loving obedience for which rational creatures are made. The power freely to choose good implies a corresponding power to choose evil. Unless we had some inclination toward evil, we would gain no merit in doing what is good.

When we violate God’s law, we know that we deserve punishment. A God who is just cannot condone evil, allowing it to be committed with impunity. When God punishes evil, His punishments may be medicinal or simply retributive. In this life punishments serve to bring about repentance and reform. If sinners fail to respond, they will justly suffer retributive punishment in hell. The possibility of hell is a necessary implication of human freedom in a moral universe. But even if we could not see the logic of it, we would have to submit to the clear teaching of Our Lord on the subject.

The death of Christ on the Cross is under one aspect a terrible evil but, considered as a loving sacrifice, it is the supreme proof of God’s love. Sufficient though it was to atone for the sins of the whole world, it does not save us without our consent. Just as we benefit from the redemptive sufferings of Christ, so too our own sufferings, offered up in the body of Christ which is the Church, can be redemptive. This last point, not mentioned in The Problem of Pain , became clear to Lewis at a later time.

In The Great Divorce , Lewis takes up the objection that the joy of the blessed in heaven would be spoiled if even a single soul were lost in hell. To this he replies that the loveless are not allowed to blackmail the universe. Hell cannot veto heaven. The souls in heaven may have pity in the active sense, but pity as a passion will cease.

With arguments such as these, Lewis feels that he has successfully made the case for letting God out of the dock. Indeed, the expression “God in the dock” is one coined by Lewis himself. Insightfully he remarks that while ancient man approached God (or even the gods) as an accused person approaches his judge, modern man has reversed the roles. Man sits on the bench and places God before him as the accused. “If God should have a reasonable defense for being the god who permits war, poverty, and disease, he is ready to listen to it. The trial may even end in God’s acquittal.”

Lewis was convinced of the imperative need for apologetics. A century ago, he said, the Church’s task was to edify those who had been brought up in the faith, but her present task is chiefly to convert and instruct infidels. The Britain of his day, Lewis maintained, was as much part of the mission field as China.

While advocating a renewed apologetics, Lewis was also conscious of its limitations. The religious person, he said, knows God primarily through experiences of prayer, worship, and forgiveness, but these experiences can be communicated, if at all, in a language resembling that of poetry. Apologetics, as a form of controversy, has to use terms that are as univocal and definable as possible. The apologist is therefore in a situation comparable to that of a witness under cross-examination trying to defend the character of a friend. The circumstances make it almost impossible to convey one’s real impression.

Notwithstanding these crippling limitations, apologetics can sometimes be relatively successful. The apologist’s task is to gather and present evidence capable of persuading reasonable persons that the Christian religion ought to be accepted. Lewis maintains that no adult comes to believe Christianity without thinking that there are good grounds for holding it is true. But the assent that flows from apologetical arguments falls short of Christian faith. Apologetics, in Lewis’ view, provides a road map, but the map is no substitute for the journey.

The relation between faith and reason becomes radically different once a person has made the act of faith. The believer enters into a personal relationship with God that involves far more than assent to propositions. He places total trust in God to such a point that he would continue to believe even if he ceased to see the reasons. Those who have experienced this interpersonal relationship know enough about God to trust Him even when He seems absent. On this ground Lewis defends what he calls “obstinacy in belief.”

Lewis proposes a very interesting definition. “Faith, in the sense in which I am here using the word, is the art of holding on to things your reason has once accepted, in spite of your changing moods.” Arguments do not secure us against the fluctuations of our moods. Many saints have experienced dark nights in which their faith seems to be unsupported by valid reasons. Yet they cling to the God whose loving embrace they have felt. Lewis chronicles an experience of this kind in his A Grief Observed . His faith was severely tested by the early and painful death of his wife, but he did not succumb.

Did he change his position in this final book? Beversluis holds that he there confessed the failure of his lifelong enterprise as an apologist and that he never recovered his assurance that a rational case could be made for Christianity. With the vast majority of Lewis scholars, I am convinced of the opposite. In the preface to The Problem of Pain Lewis already recognized that no intellectual solution could suffice to overcome the doubts that would arise in situations of grief. During the first weeks after his wife’s death he experienced this insufficiency, but in the end he came to see that God was weaning him from excessive earthly attachments and inadequate concepts so that he could fix his heart more purely on the divine reality itself”on the God who surpasses all that we can think or imagine about Him. After undergoing the painful process of purification, Lewis was confident of having grown in faith and in humility.

Lewis’ eminent success as an apologist is due to several factors. A convert from atheism, he had experienced the difficulties from within and had discovered by experience what arguments could speak to the unbeliever. He had a great gift for debating and wrote in a pleasing English style, free of heavy and technical language. He handled profound problems in simple words that could be understood by readers with no special training. Gifted with a lively imagination, he had an extraordinary facility for finding apt analogies from common life to illustrate abstract philosophical points. He was humble and unpretentious, willing to recognize the limits of his own knowledge. He concentrated on basic Christian beliefs and usually managed to avoid involvement in intra-Christian controversies.

The limits of Lewis are the flip side of his merits. Speaking to a broad and unsophisticated audience, he did not satisfy the scruples of some academicians, who found that he oversimplified complex problems. Avoiding technical terminology, he often failed to make distinctions that would be necessary to do justice to the subject matter. Having embraced no particular philosophical system other than a vague sort of Platonism, he frequently argued without the rigor expected in professional philosophical and theo logical circles.

As an apologist, moreover, Lewis tends to concentrate on the rational element in the approach to faith. But as he indicates in his own conversion story, it is not we alone who find the true faith. The God for whom we are searching has to find us, and we have to let Him do so. To speak too much as though faith were the result of a process of reasoning is a hazard built into apologetics. If Lewis had been willing to venture more deeply into theological waters, he might have spoken more extensively about the role of God in the process of conversion. Theologians in the great tradition show that divine grace influences even our initial perception of the evidences for Christianity. God’s love, at work in our hearts, often enables us to synthesize data that might otherwise appear meaningless. It gives us what some theologians call “the eyes of faith.” For this reason the search for religious truth has to be accompanied by prayer.

As Lewis’ greatest weakness, I would single out his lack of appreciation for the Church and the sacraments. In Mere Christianity he touches on baptism and Holy Communion only briefly, when discussing what we have to do once we have become Christians. He admits that he finds it rather odd that bodily acts of this kind should be the means of acquiring new life. But no doubt, he remarks, God likes material things such as food and drink. “It seems plain as a matter of history that He [Jesus] taught his followers that the new life was communicated in this way.” Lewis seems content with this rather weak defense of the sacramental system. But in his later years he developed a deeper appreciation. Speaking of Holy Communion in his posthumously published Letters to Malcolm , he writes: “Yet I find no difficulty in believing that the veil between the worlds, nowhere else (for me) so opaque to the intellect, is nowhere else so thin and permeable to divine operation. Here a hand from the hidden country touches not only my soul but my body. Here the prig, the don, the modern in me have no privilege over the savage or the child.”

In Surprised by Joy Lewis mentions that in the first years after his conversion he started attending Sunday services at his parish church, but adds: “The idea of churchmanship was to me wholly unattractive . . . .I was deeply antiecclesiastical . . . .I had as little relish to be in the Church as in the zoo. It was, to begin with, a kind of collective; a wearisome ‘get-together’ affair . . . .To me, religion ought to have been a matter of good men praying alone and meeting by twos and threes to talk about spiritual matters . . . .Hymns were (and are) extremely disagreeable to me. Of all musical instruments I liked (and like) the organ least. I have, too, a sort of spiritual gaucherie which makes me unapt to participate in any rite.”

These words, I believe, point to an individualistic and academic quality that affected Lewis’ religion almost to the end of his life. His “mere Christianity” is a set of beliefs and a moral code, but scarcely a society. In joining the Church he made a genuine and honest profession of faith”but he did not experience it as entry into a true community of faith. He found it possible to write extensively about Christianity while saying almost nothing about the People of God, the structures of authority, and the sacraments.

My own experience has been different. In becoming a Catholic, I felt from the beginning that I was joining the communion of the saints, the body to which Augustine and Aquinas, Bernard and Ignatius, belonged. I found great joy at the sense of belonging to a body of believers that stretched across the globe. The sacramental system and the authority of pastors were (and are) for me among the most attractive features of Christianity.

Still, while wishing that Lewis had projected a more ecclesial vision of Christianity, I withdraw nothing that I have said about his merits. His courage in addressing real objections, together with his keen logic and appealing rhetoric, have won him an enduring place in the history of Christian apologetics.

Avery Cardinal Dulles, S.J. , holds the Lawrence J. McGinley Chair in Religion and Society at Fordham University.

Articles by Avery Cardinal Dulles