Doubt and the Vain Search for Certainty

Taken from Doubting by Alister McGrath, a forthcoming title from InterVarsity Press. Copyright (c) 2006 by Alister McGrath. Used with permission of InterVarsity Press, PO Box 1400, Downers Grove, IL 60515.

Deep within all of us lies a longing for absolute security, to be able to know with absolute certainty. We feel that we should be absolutely sure of everything that we believe. Surely, we feel, we ought to be able to prove everything that we believe.

Yet absolute certainty is actually reserved for a very small class of beliefs. What sort of beliefs? Well, for example, things that are self-evident or capable of being logically demonstrated by propositions. Christianity does not concern logical propositions or self-evident truths (such as “2 + 2 = 4,” or “the whole is greater than the part”). Both of these are certainly true. We may be able to know such truths with absolute certainty—but what is their relevance to life? Realizing that “the whole is greater than the part” isn’t going to turn your life inside out! Knowing that two and two equal four isn’t going to tell you anything much about the meaning of life. It won’t excite you. Frankly, the sort of things that you can know with absolute certainty are actually not that important.

The things in life that really matter cannot be proven with certainty—whether they are ethical values (such as respect for human life), social attitudes (such as democracy) or religious beliefs (such as Christianity). “There is no philosopher in the world so great but he believes a million things on the faith of other people and accepts a great many more truths than he demonstrates,” wrote Alexis de Tocqueville. Richard Rorty, probably the greatest American philosopher of the twentieth century, makes this point well, when he points out that “if anyone really believed that the worth of a theory depends on its philosophical grounding, then indeed they would be dubious about physics, or democracy, until relativism in respect to philosophical theories had been overcome. Fortunately, almost nobody believes anything of the sort.” His point? That we can commit ourselves to the great worldviews of our time without having to wait for absolute proof—a proof which, by the very nature of things, is never going to happen.

The British nineteenth-century poet Lord Tennyson made this point rather nicely in his poem The Ancient Sage:

For nothing worthy proving can be proven,

Nor yet disproven; wherefore thou be wise,

Cleave ever to the sunnier side of doubt.

The beliefs which are really important in life concern such things as whether there is a God and what he is like, or the mystery of human nature and destiny. These—and a whole host of other important beliefs—have two basic features. In the first place, they are relevant to life. They matter, in that they affect the way in which we think, live, hope and act. In the second place, they cannot be proved (or disproved) with total certainty. By their very nature, they make claims that cannot be proved with certainty. At best, we may hope to know them as probably true. There will always be an element of doubt in any statement which goes beyond the world of logic and self-evident propositions. Christianity shares this situation. It is not unique in this respect: an atheist or Marxist is confronted with precisely the same dilemma, as we well see in the next chapter. Anyone who wants to talk about the meaning of life has to make statements which rest on faith, not absolute certainty. Anyway, God isn’t a proposition—he’s a person!

We cannot see God; we cannot touch him; we cannot demand that he give a public demonstration of his existence or character. We know of God only through faith. Yet the human mind wants more. “Give us a sign! Prove it!” It is an age-old problem. Those who heard Jesus’ teaching wanted a sign (Matthew 12:38)—something which would confirm his authority, which would convince them beyond any doubt.

To believe in God demands an act of faith—as does the decision not to believe in him. Neither is based upon absolute certainty, nor can they be. To accept Jesus demands a leap of faith—but so does the decision to reject him. To accept Christianity demands faith—and so does the decision to reject it. Both rest upon faith, in that nobody can prove with absolute certainty that Jesus is the Son of God, the risen saviour of humanity—just as nobody can prove with absolute certainty that he is not. The decision, whatever it may be, rests upon faith. There is an element of doubt in each case. Every attitude to Jesus—except the decision not to have any attitude at all!—rests upon faith, not certainty. Faith is not belief without proof, but trust without reservations—a trust in a God who has shown himself worthy of that trust. To use a Trinitarian framework: God the Father makes those promises; God the Son confirms them in his words and deeds; and the Holy Spirit reassures us of their reliability, and seals those promises within our heart.

These points are reflected in the American writer Sheldon Vanauken’s account of his mental wrestling before his conversion at Oxford. He found himself caught in a dilemma over the role of proof in faith, which many others have experienced.

There is a gap between the probable and the proved. How was I to cross it? If I were to stake my whole life on the risen Christ, I wanted proof. I wanted certainty. I wanted to see him eat a bit of fish. I wanted letters of fire across the sky. I got none of these ... It was a question of whether I was to accept him—or reject him. My God! There was a gap behind me as well! Perhaps the leap to acceptance was a horrifying gamble—but what of the leap to rejection? There might be no certainty that Christ was God—but, by God, there was no certainty that he was not. This was not to be borne. I could not reject Jesus. There was only one thing to do once I had seen the gap behind me. I turned away from it, and flung myself over the gap towards Jesus.

There is indeed a leap of faith involved in Christianity—but it is not an irrational leap into the dark. The Christian experience is that of being caught safely by a loving and living God, whose arms await us as we leap. Martin Luther put this rather well: “Faith is a free surrender and a joyous wager on the unseen, untried and unknown goodness of God.”

All outlooks on life, all theories of the meaning of human existence, rest upon faith, in that they cannot be proved with absolute certainty. But this doesn’t mean that they’re all equally probable or plausible! Let’s take three theories of the significance of Jesus to illustrate this point.

1. We have been redeemed from sin by the death and resurrection of Jesus Christ.

2. Jesus and his disciples were actually the advance guard of a Martian invasion force, who mistook earth for the planet Venus on account of a navigation error.

3. Jesus was not really a person, but was really a hallucinogenic mushroom.

Although none of these can be proved or disproved with absolute certainty, it will be obvious that they cannot all be taken with quite the same degree of seriousness!

Let’s be quite clear: Nobody can prove Christianity with total certainty. But that’s not really a problem. The big questions concern the reliability of its historical foundations, its internal consistency, its rationality, its power to convert, and its relevance to human existence. As C. S. Lewis stressed in Mere Christianity, Christianity has exceptionally fine credentials on all counts. Look into them. You can totally commit yourself to the gospel in full confidence, as a powerful, credible and profoundly satisfying answer to the mystery of human existence. Faith is basically the resolve to live our lives on the assumption that certain things are true and trustworthy, in the confident assurance that they are true and trustworthy, and that one day we shall know with absolute certainty that they are true and trustworthy.

A superficial faith is a vulnerable faith

Superficiality is a curse of our age. The demand for instant satisfaction leads to superficial personal relationships and a superficial Christian faith. Many students discover Christianity for the first time while at college or university. This discovery very often happens alongside other important events like leaving the parental home, falling in love, or gaining independence of thought and action. As a result, initial emphasis very often falls on the emotional and experiential aspects of Christianity. There is nothing wrong with this! Christianity has abundant resources for those who wish to place emphasis on the role of experience in the life of faith. But there is more to faith than that.

Faith has three main elements. In the first place, it is trust in God. It is a confidence in the trustworthiness, fidelity and reliability of God. It is about rejoicing in his presence and power, being open to his prompting and guidance through prayer, and experiencing the motivation and comfort of the Holy Spirit. It is a deep sense of longing to be close to God, of wanting to praise his name, of being aware of his presence. In many ways, this aspect of Christian faith is like being in love with someone: you want to be with them, enjoying their presence and feeling secure with them. It concerns the heart, rather than the head; it is emotional, rather than intellectual. It is the powerhouse of Christian life, keeping us going through the difficult times and exciting us during the good times.

The difficulty is that all too many people seem to get no further than this stage. Their faith can easily become nothing more than emotion. It can become superficial, lacking any real depth. It seems shallow. It has not really taken root, and is very vulnerable. Yet faith can only flourish when it sinks deep roots. There is more to faith than emotion, experience and feelings, however important they may be to you. Christianity isn’t just about experiencing God—it’s about sticking to God. A mature faith is something secure, something that you can rely on. If your faith is not deeply rooted, you will be tempted to find security in something else, only to find that this alternative will fail you (Matthew 7:24–27).

In the second place, faith is understanding more about God, Jesus Christ and human nature and destiny. By its very nature, faith seeks understanding. It seeks to take root in our minds, as we think through the implications of our experience of the risen Christ. To become a Christian is to encounter the reality of God; to become a disciple is to allow this encounter to shape the way in which we think—and act.

For in the third place, faith is obedience. Paul speaks of the “obedience that comes from faith” (Romans 1:5) making the point that faith must express itself in the way we act. “Faith is kept alive in us, and gathers strength, from practice more than speculation” (Joseph Addison). Or, as the Oxford writer W. H. Griffith-Thomas put it, nicely linking these together:

[Faith] commences with the conviction of the mind based on adequate evidence; it continues in the confidence of the heart or emotions based on conviction, and it is crowned in the consent of the will, by means of which the conviction and confidence are expressed in conduct.

And it’s at this point that doubt can come in, simply because you have allowed your faith to be shallow. The New Testament often compares faith to a growing plant—a very helpful model to which we shall return frequently in this book. It is very easy to uproot a plant in its early stages of growth; once it has laid down roots, however, it is much harder to dislodge it. By failing to allow their faith to take root, some Christians make themselves very vulnerable to doubt. They haven’t thought about their faith. For example, someone may raise a question about the historical evidence for the existence of Jesus. They don’t know the answer. So doubts begin to creep in—often quite needless doubts, it must be said.

If this happens to you, view it in the right way. The gospel isn’t an illusion that is shown up for what it really is by hard questions—like the emperor’s clothes in the famous story by Hans Christian Andersen. The fact that you haven’t been able to give adequate answers to some person’s questions or objections to your faith doesn’t mean that Christianity falls to pieces the moment people start asking hard questions! It doesn’t mean that you’ve committed some kind of intellectual suicide by becoming a Christian. It shouldn’t mean that your confidence and trust in the gospel collapse, like a deflating balloon, just because someone asked you a question you couldn’t answer. It does, however, mean that you haven’t thought these things through.

Your faith is real—but it is not mature. It may be a little shallow and superficial. But—and this matters enormously!—faith can grow, and it strengthens as it grows. It needs to take root, and grow into a strong, vibrant plant. The problem often lies not in the gospel, but in the nature and depth of your response to it. You have allowed the gospel to capture your imagination, but not your mind. Your faith is shallow, when it should be—and can be—profound. Your failure here ought to be a challenge to you to go away and read more deeply about these matters, or talk them over with other more experienced Christians. In addition to helping you deepen your understanding of these things, doing this will enable you to be more helpful to those interested in learning about Christianity.

This doesn’t mean that you should try harder to believe, as if it were by wishing harder that difficulties disappear. This idea of “faith in faith” won’t get you very far. You should see doubt as pointing to your faith being based on weak foundations. It is those foundations which need attention. A superficial faith is a vulnerable faith, easily (and needlessly) upset when confronted with questions or criticism.

Faith is like reinforced concrete. Concrete which is reinforced with a steel framework is able to stand far greater stress and strain than concrete on its own. Experience which is reinforced with understanding will not crumble easily under pressure. Again, faith is like the flesh and bones of a human body. Just as the human skeleton supports the flesh, giving it shape and strength, so understanding supports and gives shape to Christian experience. Without the skeleton, the human body would collapse into a floppy mass. Without flesh, a skeleton is lifeless, hollow and empty; without the skeleton, flesh lacks shape, form and support. Both flesh and bones are needed if the body is to grow and to function properly. Faith needs the vitality of experience if it is to live – and the support of understanding if it is to survive. So reinforce your faith with understanding.

Doubt in Other Worldviews: The Case of Atheism

In the previous chapter, I made an important point that needs to be explored much more thoroughly. Christians tend to think that doubt is a problem for them alone. But it’s not. It’s a problem for any worldview—whether Jewish or Islamic, atheist or religious. Appreciating this point is essential to seeing doubt in its proper perspective. As I used to be an atheist myself, I am going to explore the place of doubt within atheism.

Most people—including, it has to be said, many atheists themselves!—have the rather simple idea that atheism is about fact, whereas Christianity is about faith. Their ideas are factual; those of Christians are unproven. But it’s not like that. Let me explain by asking a question: can I prove with certainty that there is a God? The short answer is “no.” If you have time to study the history of the philosophical arguments for the existence of God, you’ll know that they are suggestive, but not conclusive. It’s pretty much the universal consensus within philosophy that rational argument does not settle the question of God’s existence, one way or the other. The atheist philosopher Kai Nielsen makes this point clearly when he writes: “To show that an argument is invalid or unsound is not to show that the conclusion of the argument is false . . . All the proofs of God’s existence may fail, but it still may be the case that God exists.” Argument is not going to settle this question, one way or the other. And that means that the outcome is uncertain for the atheist.

Now let’s pause here, because you need to appreciate something important. Christians often tend to see only one side of that statement: that nobody can rationally prove that God exists. But can you see that there is another side to it? That nobody can disprove that God exists? The Christian who believes in God thus does so as a matter of faith. But can you see that the atheist has to do the same? That her belief that there is no God is exactly that—a belief! Because she cannot prove that there is no God, her atheism is also a faith.

Atheists don’t like this argument, but it is correct. The simple fact is that when anyone starts making statements about the meaning of life, the existence of God, or whether there is life after death, they are making statements of faith. You can’t prove, either by rational argument or by scientific investigation, what life is all about. Whether you are Christian or atheist, you share the same problem. It’s essential that you appreciate that it’s not just Christians that make these statements as a matter of faith. And because they make these statements as a matter of faith, they are just as vulnerable to doubt as anyone else—Christians included. We’re all in the same situation.

Let’s explore this a little further, by looking at two important issues: atheist arguments for the non-existence of God, and so-called “scientific atheism,” which holds that science disproves God’s existence. Both, as we shall discover, are hopeless overstatements of the real situation.

Atheist arguments against the existence of God

Atheists often tell Christians that their faith is infantile. It’s just fine for the minds of impressionable young children, but laughable in the case of adults. We’ve grown up now, and need to move on. Why should we believe things that can’t be scientifically proved? Faith in God, many atheists argue, is just like believing in Santa Claus and the Tooth Fairy. When you grow up, you grow out of it. And if you don’t, then you are either mentally retarded or intellectually dishonest.

But this is just rhetoric—the attempt to discredit a belief by heaping ridicule upon in. In fact, it is this argument itself that is childish. If this simplistic argument has any plausibility, it requires a real analogy between God and Santa Claus to exist—which it clearly does not. There is no serious evidence that people regard God, Santa Claus and the Tooth Fairy as belonging to the same category. I stopped believing in Santa Claus and the Tooth Fairy when I was about six years old. After being an atheist for some years, I discovered God when I was eighteen, and have never regarded this as some kind of infantile regression. As I noticed while researching my book The Twilight of Atheism, a large number of people come to believe in God in later life—when they are “grown up.” I have yet to meet anyone who came to believe in Santa Claus or the Tooth Fairy late in life! So let’s leave this sort of nonsense behind, and look at a more serious argument, often advanced by atheists.

The most sophisticated atheist arguments against God date from the nineteenth and early twentieth centuries, and are found in the writings of Ludwig Feuerbach, Karl Marx, and Sigmund Freud. Although they are slightly different, there is a common structure to each. Here it is, set out step by step.

1. There is no God.

2. But some people believe in God.

3. Since there is no God, this must be the result of some kind of delusion or wishful thinking.

4. People believe in God because they want to. Their faith is just a wish-fulfilment.

5. So faith in God is just a human invention, corresponding to a human need. (Atheists differ over how this need arises: Marx puts it down to social alienation and Freud to psychological forces).

Atheists regularly use these arguments against Christians, as I have found out in university debates. Their faith often rests heavily on this kind of argument. But let’s look at this argument in more detail. On closer examination, it turns out to be as full of holes as Swiss cheese. There are three major points that need to be made.

1. The argument is circular. It presupposes that there is no God. Step (5) depends on step (1). If there was a God, then there would be no delusion, would there? It proves nothing, except that atheism is logically self-sufficient. And so is just about every worldview. The important question is: how well does it relate to the real world? The argument merely restates its presuppositions as its conclusions.

2. It is logically flawed. It is certainly true that nothing exists just because I want it to. I might long to have a pile of hundred dollar bills beside me, so that I could pay off some of my debts. But wanting something doesn’t make it happen! We can all agree on that, I think. But—and it is a very big “but”—it does not follow that, because I want something, it cannot exist. Do you see this point? Imagine a man who has fallen overboard from a ship. He wants there to be a helicopter to rescue him. So helicopters can’t exist, because he wants them to? Or the specific helicopter that is already on its way to rescue him cannot exist, because he needs it? Or imagine that you feel very thirsty. You need a drink of water. So water can’t exist, because you want it? Or the specific glass of water that you are about to drink cannot exist, because you need it just then? It just doesn’t follow. As C. S. Lewis so often pointed out, it looks as if God has made us in such a way that we long for him—and then go on to find him! The desire for God originates from God—and eventually leads to God! So much for the logic of the argument against God.

3. The argument works just as well against atheism. This is a devastating point. The atheist’s argument goes like this: you want there to be a God. So you invent him. Your religious views are invented to correspond to what you want. But this line of argument works just as well against atheism. Imagine an extermination camp commandant during the Second World War. Would there not be excellent reasons for supposing that he might hope that God does not exist, given what might await him on the day of judgment? And might not his atheism itself be a wish-fulfillment? And as cultural historians have pointed out for many years, based on their analysis of European history from about 1780 to 1980, people often reject the idea of God because they long for autonomy—the right to do what they please, without any interference from God. They don’t need to worry about divine judgment. They reject belief in God because it suits them. That’s what they want. But that doesn’t mean that this is the way things really are.

This point was made superbly by the Polish philosopher and writer Czeslaw Milosz, who won the Nobel Prize for Literature in 1980. Parodying the old Marxist idea that religion was the “opium of the people,” he remarked that a new opium had taken its place—rejection of belief in God on account of its implications for our ultimate accountability. “A true opium of the people is a belief in nothingness after death—the huge solace of thinking that for our betrayals, greed, cowardice, murders we are not going to be judged.”

Atheism thus depends on a core belief that it cannot verify. Do you see the importance of this point? Atheists live out their lives on the basis of the belief that there is no God, believing that this is right, but not being able to prove it conclusively. Hardly surprisingly, atheists have tried to buttress their beliefs in other ways. One of them is to appeal to the natural sciences. These, we are told with great confidence by atheists, have disproved belief in God. But is this really the case?

The inconclusive case of scientific atheism

The twentieth century has seen many atheist scientists insist that science has eliminated belief in God. The Oxford zoologist and atheist propagandist Richard Dawkins is a good example of this kind of writer. His simplistic overstatements are regularly criticized by other scientists as representing a serious abuse of the scientific method. The simple truth is that the natural sciences neither prove nor disprove the existence of God. So either we have to give up this discussion as meaningless, or we settle it on other grounds.

You will have no problem finding writers who talk about the “limitless powers of science” to explain things, or who argue that only scientific knowledge can be taken seriously. Here is the British atheist writer Bertrand Russell on this point: “Whatever knowledge is attainable, must be attained by scientific methods; and what science cannot discover, mankind cannot know.” Yet this is a ludicrous overstatement. First, it is not actually a scientific statement, so it disqualifies itself as being true knowledge! Yet more seriously, it would mean that we can never answer questions about the meaning of life, even from an atheist perspective—something that Russell seems to overlook.

Yet science has its limits. That’s no criticism of science, by the way – just a recognition of its boundaries. Within those boundaries, it is highly competent. But outside them, it cannot deliver the simple answers that some hoped for. Sir Peter Medawar, who won a Nobel Prize for Medicine for his discovery of acquired immunological tolerance, was well aware of the limits of science. His words deserve to be pondered:

The existence of a limit to science is, however, made clear by its inability to answer childlike elementary questions having to do with first and last things—questions such as “How did everything begin?’; ‘What are we all here for?’; ‘What is the point of living?’

The point is clear: science is wonderful when it comes to discovering the chemical structure of planetary atmospheres, the cause of cancer, or finding a cure for blood poisoning. But can it tell us why we are here? Or whether there is a God or not? No. It has its limits. And those who insist—quite wrongly—that science demands or necessitates or proves atheism have some serious explaining to do. Let’s hear Sir Peter again:

There is no quicker way for a scientist to bring discredit upon himself and upon his profession than roundly to declare—particularly when no declaration of any kind is called for—that science knows, or soon will know, the answers to all questions worth asking, and that questions which do not admit a scientific answer are in some way non-questions or ‘pseudo-questions’ that only simpletons ask and only the gullible profess to be able to answer.

Let’s be clear about this. It is perfectly possible to interpret the natural sciences in atheist, theistic and agnostic ways. The sciences can be “spun” in ways making them support disbelief in God, belief in God, or scepticism. But the sciences demand none of these interpretations. Stephen Jay Gould, widely regarded as America’s greatest evolutionary biologist before his recent death from cancer, was no religious believer. But he was adamant that his own religious scepticism could not be derived from the sciences.

To say it for all my colleagues and for the umpteenth million time (from college bull sessions to learned treatises): science simply cannot (by its legitimate methods) adjudicate the issue of God’s possible superintendence of nature. We neither affirm nor deny it; we simply can’t comment on it as scientists.

Gould rightly insists that science can work only with naturalistic explanations; it can neither affirm nor deny the existence of God. And those who argue that it disproves God have just lost the plot, imposing their atheism on a neutral science.

God is simply not an empirical hypothesis which can be checked out by the scientific method. As Stephen Jay Gould and others have insisted, the natural sciences are not capable of adjudicating, negatively or positively, on the God-question. It lies beyond their legitimate scope. There is simply no logically watertight means of arguing from observation of the world to the existence, or non-existence of God. This has not stopped people from doing so, as a casual survey of writings on both sides of the question indicates. But it does mean that these “arguments” are suggestive, and nothing more. The grand idea that atheism is the only option for a thinking person has long since passed away, being displaced by a growing awareness of the limitations placed on human knowledge, and an increased expectation of humility in the advocation of religious choices.

Two major surveys of the religious beliefs of scientists, carried out at the beginning and end of the twentieth century, bear witness to a highly significant trend. One of the most widely held beliefs within atheist circles has been that, as the beliefs and practices of the “scientific” worldview became increasingly accepted within western culture, the number of practicing scientists with any form of religious beliefs would dwindle to the point of insignificance. A survey of the religious views of scientists, undertaken in 1916, showed that about 40% of scientists had some form of personal religious beliefs. At the time, this was regarded as shocking, even scandalous. The survey was repeated in 1996, and showed no significant reduction in the proportion of scientists holding such beliefs, seriously challenging the popular notion of the relentless erosion of religious faith within the profession. The survey cuts the ground from under those who argued that the natural sciences are necessarily atheistic. Forty percent of those questioned had active religious beliefs, 40% had none (and can thus legitimately be regarded as atheist), and 20% were agnostic.

The stereotype of the necessarily atheist scientist lingers on in western culture at the dawn of the third millennium. It has its uses, and continues to surface in the rehashed myths of the intellectual superiority of atheism over its rivals. The truth, as might be expected, is far more complex and considerably more interesting.

The point of these reflections is obvious. Any worldview—atheist, Islamic, Jewish, Christian or whatever—ultimately depends on assumptions that cannot be proved. Every house is built on foundations, and the foundations of worldviews are not ultimately capable of being proved in every respect. Everyone who believes anything significant or worthwhile about the meaning of life does so as a matter of faith. We’re all in the same boat. And once you realize this, doubt seems a very different matter. It’s not a specifically Christian problem—it’s a universal human problem. And that helps to set it in its proper perspective.

Alister McGrath is Professor of Historical Theology at Wycliffe Hall, Oxford, where he also lectures at RZIM’s Oxford’s Centre for Christian Apologetics (OCCA). For more about Professor McGrath and his writings, see his website

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