Science and Theology, Parallelisms

I. On the Endeavour of Science

1. Science is Concerned with the Rational Exploration of the Material World. Science is the search for an understanding of the nature and pattern of the physical world. That may seem a very obvious thing to say, and most scientists would be astonished to learn that there was any other way of thinking about their subject. After all, what else would make worthwhile all the weary labour and frustration involved in scientific research, if it were not the thought that in the end we would learn something new about the way the world is? Yet many philosophers in the twentieth century have suggested that this is not what science is about at all. They see difficulties in the claim that science tells it like it is. They point out that its procedures are not as straightforward as people think.

A popular view of how science works is that someone makes a prediction on the basis of a theory, then an experiment is done to see if the prediction works, and if it does the theory is verified. But this simple picture of the unambiguous confrontation of theory and experiment doesn't hold up to careful consideration. The trouble is that theory and experiment are intertwined in subtle ways which are hard to disentangle. You might show me some marks on a photographic plate and we would no doubt agree on the pattern they formed. But that pattern by itself is of no real interest. It only becomes so when it is theoretically interpreted as indicating the decay of an Ω particle. All significant scientific facts are “theory-laden.” In a famous phrase, we can only look at the physical world wearing “spectacles behind the eyes;” we view it from an adopted perspective through which we interpret, and select out from the flux of events, what is truly significant. If that is the case, maybe the results of science are just “an agreement to see it that way,” unconsciously chosen by the invisible college of scientists under the pressures of communal expectation. Philosophers who take this view claim that the physicists’ picture of the world is the result of social construction rather than true discovery. The success of science is only a purely instrumental success, the attainment of “manners of speaking” which are effective in getting things done but not in describing things as they actually are. Talk of electrons is a way of constructing devices like the electron microscope, not a discovery of what matter is actually made of.

I am quite sure that this position is wrong. I assert that science is the rational exploration of what is the case (cf. Polkinghorne, 1986 and 1991). For the present, two considerations must suffice in defence of this position.

The first is to ask what could make these “manners of speaking” so effective if it were not that they describe the way things are? The idea of electrons enables us not only to make electron microscopes but also to do many other things, such as work with superconducting devices and understand much of chemistry. The only rational explanation of this widespread success is that there actually are electrons that behave in the ways that physics describes. Any other account would make sustained instrumental success a mysterious miracle. Secondly, the whole feel of doing science is one of discovery and not construction. Time and again the physical world resists our expectation and we have to struggle very hard to understand it. Far from our moulding our experiences into pleasing shapes of our own choosing, we are continually challenged and surprised by what we encounter.

Yet the criticisms of the philosophers do teach us some useful things. Science is not as straightforward an activity as we might have supposed without their analysis. We do indeed wear “spectacles behind the eyes.” We can only approach the physical world from a previously chosen point of view. Even in science, like St. Augustine stated for theology, we have to “believe in order to understand.” Of course, that initial belief must be open to correction in the light of subsequent investigation. That is what makes science a rational activity. Science, as Michael Polanyi (1891-1976) argued so cogently, is also a personal activity (cf. Polanyi, 1958). By that I mean that it involves acts of judgment of a kind that cannot be delegated to computers but which must be made by people who have acquired tacit skills in the course of an apprenticeship to a living intellectual tradition. For example, in any experiment one must eliminate what, in the trade, we call “background,” the unwanted spurious events arising from causes other than the phenomena we are trying to investigate. The assessment that this has been done successfully rests on experience and intuition and it can never be reduced to the following of a set of rules.

We are right to take science seriously but not because it is wholly different in character from all other forms of rational inquiry. All such quests for truth involve an inescapable degree of intellectual daring, a necessary commitment to a corrigible point of view which is the only basis for attaining deeper understanding. Once we have recognized that, the very success of science in its own rational endeavour will encourage us to take with equal seriousness other attempts to explore different aspects of the many-layered reality of our experience.

2. The Physical World is Rationally Transparent. We are so used to understanding the physical world that most of the time we take this for granted. It makes science possible, but surely it is a very significant aspect of the way things are. In particular, let us pause to recognize, in Eugene Wigner's pregnant words, the “unreasonable effectiveness of mathematics.” It is our continual experience that the mathematical expressions of the theories which describe the universe are endowed with the unmistakable character of mathematical beauty. Why should this be so? After all, mathematics arises from the free explorations of the human mind, but some of its most elegant and harmonious patterns are found actually to occur in the world around us. So characteristic is this of the discoveries of physics that Paul Dirac (1902-1984) once said “it is more important to have beauty in one’s equations than to have them fit an experiment.” (Dirac, 1963, p. 47). Of course, he didn't mean that empirical success was unimportant, but its apparent failure might be due to bad calculations or even erroneous experiments. But to have ugly equations would be an irredeemable disaster. They couldn't be right.

Mathematics proves the key to unlock the secrets of the universe. Why should this be so? Why do the reason within (mathematics) and the reason without (physics) fit together so perfectly? Of course, at the everyday level, evolutionary biology provides an explanation. If our ordinary thoughts did not fit our ordinary experience, we should not have survived in the struggle for existence. But the unreasonable effectiveness of mathematics is a much more profound fact than anything that such banal considerations could explain. It applies to the counterintuitive quantum world, in its probabilistic elusiveness so very different from the world of everyday experience. That world is unpicturable for us in its strangeness, but it is not unintelligible to us, though its understanding demands the use of very abstract and sophisticated mathematics. I cannot believe that our power to conceive of such mathematics is just a spin-off from our ancestors having had to dodge the attacks of sabre-toothed tigers.

Science itself cannot explain the rational transparency of the physical world (which makes its enterprise possible) nor the rational beauty of that world (whose discovery makes science worthwhile). It is part of the founding faith of science that this should be so. Yet it does not seem sufficient just to say “That's the way it is, and a bit of good luck for you chaps who happen to be good at maths!” In the intelligibility of the physical world we encounter an insight derived from science and calling for an explanation, even though that explanation is beyond science's power to offer. One could call the universe's intelligibility a signal of transcendence, an intimation that there is more to understand than has met the scientific eye.

3. The Fruitful History of the Universe depends upon “Fine Tuning” in its Physical Laws. Our universe started very simply, a bit more that thirteen billion years ago. Today it is richly varied, containing within it such interesting and complicated consequences as we humans. The tale of cosmic evolution is one of an astonishing fruitfulness. At least in outline, we have attained a good deal of scientific understanding of the processes by which that fertile history came about. We can also play intellectual games (with serious intent) and consider how things might have gone if the universe had been somewhat different. For instance, suppose the force of gravity had been a bit stronger than it is, or electromagnetism a bit weaker? I imagine that one would have expected that such changes would modify things, but not in a very drastic way. It has been very surprising, therefore, to realize that in fact quite small changes in any of these basic physical laws would have rendered cosmic history boring and sterile. As the results we indicate under the label Anthropic Principle seem to show, a fruitful world —a world capable of evolving human beings— is a very special universe. Its “finely-tuned” laws make it a cosmos in a trillion.

Many considerations point to that surprising conclusion. Let me just sketch two of them. A fruitful universe must have the right sort of stars in it. They have two indispensable roles to play. One is as providers of energy for life. There must be stars capable of burning steadily for billions of years, just as our sun has been doing. The second role is to provide the chemical elements which are the raw materials for life. Because the very early universe is very simple, it can only make the two simplest elements, hydrogen and helium. They do not provide the possibility for a rich enough chemistry to enable life to develop. For that one needs heavier elements like carbon and oxygen and so on. These can only be made in the nuclear furnaces of stars. Every atom of carbon in your body was once inside a star; we are all made from the ashes of dead stars. And if the elements thus made are actually to be available for the evolution of life, they must be made accessible by the supernova explosion of some of these stars as they reach the end of their nuclear lives. It turns out that these stellar requirements place very tight limitations on all the intrinsic forces of nature if they are to prove capable of fulfilment.

The second consideration I want to mention, is the size of the universe. Our cosmos contains at least 10^22 stars. It is unimaginably vast, and sometimes we feel haunted at the thought of such immensity. We should not, for if all those trillions of stars were not there, we should not be here to be upset by the thought of them. Only a universe as big as ours could have lasted the fifteen billion years that are needed to make men and women. It's a process that can't be hurried.

The Anthropic Principle represents a kind of anti-Copernican revolution in our cosmological thinking. We do not live at the centre of the universe, but neither do we live in just “any old world.” Instead we live in a universe whose constitution is precisely adjusted to the narrow limits which alone would make it capable of being our home. Once more we encounter what one might consider to be a signal of transcendence. Science does not explain the laws of nature; they are the given foundation of its endeavour. Yet those laws do not seem, in their anthropic fine-tuning, to be without the demand for some further explanation. It is scarcely enough to say “We're here because we're here, and that's that.” Is there something going on in what is happening in the physical universe, that raises cosmic process beyond the level of mere brute occurrence?

4. The Physical World is Endowed with True Becoming and it is Often Surprising. In the 18th and 19th centuries, people thought of the universe as if it were a gigantic piece of cosmic clockwork. The 20th century has seen the death of such a merely mechanical account. Whatever the universe is, it is something more subtle and more supple than that. In part this realization stems from the cloudy unpredictability of quantum mechanics, lurking at the subatomic roots of the world. But more significantly still, we have recently come to realize that even the physics of the everyday is not as mechanical as we once thought it to be. This insight is given the somewhat inapt name of the dynamical theory of chaos (cf. Gleich, 1988). It turns out that even in a Newtonian universe, most systems of any degree of complexity are so exquisitely sensitive to the finest detail of their circumstance that their behaviour is radically unpredictable. You will not be surprised that this first came to light from studies of models of the weather! It is sometimes called the butterfly effect: that the Earth's weather systems are so sensitive that a butterfly stirring the air with its wings in China today will have consequences for the storms over Oxford in a few weeks time. Since we can't possibly know about all those Chinese butterflies, we cannot reliably predict what will happen in the future.

This profound unpredictability is very surprising, but you might argue that it is just an expression of our ignorance. I want to say more than that. We physicists are realists. On our T-shirts we have written the rousing slogan: “Epistemology Models Ontology”; what we can know is a guide to what is actually the case. On that understanding, our ignorance of the future is to be interpreted as the sign that the future is, in fact, open. Hence my claim that we live in a world of true becoming. I have suggested that the extra causal principles which bring about an actual future within the open possibilities of a world of becoming, have the character of “active information” and represents a kind of top-down causality operating within wholes, which complements the bottom-up energetic causality of parts (which is what physics describes) (cf. Polkinghorne, 1991, ch. 3). We begin to get the faintest glimmer of how mind and matter might relate in our experience of human agency. In the next section, I shall want to explore how this idea might also provide a way of thinking about divine providential action in a manner which is fully consistent with all that we know scientifically about physical process.

If the study of science teaches one anything, it is not to take everyday thought as the measure of all that is. In fact, the continually surprising character of the physical world is one of those features which rewards the scientific investigator. One never knows what unexpected aspect is next to be revealed.

The degree to which commonsense notions prove in need of revision is often very considerable, extending in the case of quantum theory even to logic itself. If I say to you that Bill is at home and that he is either drunk or sober, you will deduce that you will either find Bill at home drunk or you will find him at home sober. The learned would say that you have applied the distributive law of logic to reach this apparently harmless conclusion. Yet if we replace Bill by an electron, or any other quantum entity, the same line of argument no longer applies. That is because classical logic, as codified by Aristotle, depends upon the law of the excluded middle; it has no middle term between (A) or (not A). That sharp either/or is removed by quantum theory, which permits the probabilistic adding together of possibilities which common sense would declare unmixable. An electron can be in a state which is a mixture of (here) and (not here), which yields a possibility undreamed of by Aristotle: (sometimes here). In consequence, a new kind of logic, quantum logic, had to be invented by Birkhoff and von Neumann to deal with this situation.

One of the general consequences of the discovery of quantum theory has been to enlarge our imagination of what is possible. In 1900 it would have seemed obvious that entities could be waves (spread out and flapping up and down) or little particles (small bullets) but not both. We all know that light, and all other quantum entities, nevertheless sometimes behave in a wavelike way and sometimes in a particle like way. It is less widely recognized that in 1927 Paul Dirac invented a formalism (quantum field theory) which perfectly reconciles these behaviours without a taint of paradox. Quantum theory delivers us from an undue tyranny of common sense.

5. The Investigation of the Pattern and Structure of the Physical World is Exciting. Like every worthwhile activity, science has its weary routine and the frustrations that come from lines of inquiry which eventually prove fruitless. At the end of the day, the waste-paper basket of a theoretical physicist is likely to contain a lot of crumpled pieces of paper. Why then do we do it? The pay-off for all that labour is the sense of wonder at the beautiful order revealed to our investigation. There is something deeply intellectually satisfying in the patterns thus revealed. Einstein often spoke of the pleasure he felt in the harmony of natural law. There is a profound character to the structure revealed, which often greatly exceeds our puny prior expectations.

Among the most exciting discoveries in physics have been those unifying insights which reveal that apparently disparate phenomena and effects are in fact the varied manifestations of a single reality. In the 19th century, the experimental discoveries of Hans Christian Oersted and Michael Faraday and the theoretical genius of James Clerk Maxwell, succeeded in unifying electric and magnetic phenomena in the single subject of electromagnetism. In our own century, Steven Weinberg and Abdus Salam, showed that, despite striking differences in their properties, electromagnetism and the weak nuclear force (responsible for radioactive decays) are, in fact, the single fruit of a yet more profound synthesis. At present, the search is on for even more general Grand Unified Theories (GUTs) which will draw the other forces of nature (the strong nuclear force and gravity) into a single account. There are considerable difficulties yet to be surmounted in this ambitious programme, but most of us hope and expect that one day it will find its fulfilment.

There is a grandeur in the pattern and structure of the physical world that is profoundly exciting to discover and deeply satisfying to contemplate. The word “wonder” is one that scientists habitually use to describe their experiences and to justify the great endeavour in which they are engaged.

6. Yet Science is Problematic. In the public mind, science is the rational activity. I have already explained why I do not think that it is wholly different in kind from other forms of rational inquiry. Its great success stems from its self-limitation to certain types of question addressed to certain aspects of experience which, because of their objective and improved character, are open to the manipulation and interrogation by means of the experimental method.

Even within these narrow confines, however, science does not succeed at any time in achieving a completely resolved and satisfactory rationality. It proves itself capable of living with unsolved problems —not, of course, with complacency about that situation, but with a realistic acknowledgement of a necessary degree of provisionality about its current understanding. Two examples drawn from 20th century science make the point.

Quantum mechanics has been outstandingly empirically successful since its articulation in its modern form in the mid-1920s. Originally conceived of in order to deal with problems in atomic physics, it has proved equally able to cope with the dynamics of quarks and gluons, constituent entities which are a hundred million times smaller than atoms. Yet, while we can use quantum theory to such great effect, we still do not understand it properly. The cause of our perplexity is the measurement problem (cf. Polkinghorne, 1984, ch. 6). How does it come about that the fitful and elusive quantum world yields an unambiguous (if not always identical) answer on each occasion of observational inquiry? The wave function for an electron assigns it a probability for being 'here' and a probability for being 'there', but when we actually investigate where it is, each time we will receive a definite answer, sometimes 'here', sometimes 'there', but never both. How does this come about? It is rather humiliating for a physicist to have to tell you that there is no universally agreed and satisfactory answer to that entirely reasonable question. I do not have time to go into the various rival responses, or to discuss the perplexities which bedevil each of them. I do not believe the matter will remain unresolved for ever, but it is certainly currently the case that, though quantum theory provides us with many explanations of phenomena, we still have not attained a wholly satisfactory understanding of what it implies about the nature of physical reality.

My second example also involves quantum theory, but in this case it is its relationship to general theory of relativity which I wish to discuss. The latter is the modern theory of gravity but the application of quantum mechanics to it has proved a problem of intractable difficulty. There are hopeful directions in which to look for a resolution of this problem, with the theory of superstrings being the presently favoured candidate for its solution, but physics has lived for more than sixty years with two of its fundamental theories imperfectly reconciled with each other.

7. Science has Things to say to Theology. It is impossible to read out a general metaphysical point of view (such as would be a theological account of what is the case) from the consideration of physics alone. Such a comprehensive understanding must draw upon insights and experience going far beyond the self-limited realm of science itself. Physics does not determine metaphysics, but it certainly constrains it. It is not possible to erect an arbitrary metaphysical edifice upon a given basis of physical understanding. The proper relationship between science and theology is one of 'consonance'; the discoveries of physics will impose constraints upon the tone and character of theological discourse.

We now know that the universe has had a history. Far from the world as we experience it having come into being almost instantaneously and “ready made,” it was once very different from the way it is today. Its many-billion-year history of evolving fruitfulness will discourage any thought of a Creator who works by magic. He is not a God in a hurry, but rather he is patient and subtle in relation to a world which he has allowed largely to “make itself.” The theologian may well reflect that there is unlikely to be any other way in which love would choose to work.

The physical world as science discerns it, is one in which order and disorder interlace and fertilize each other. The creative interplay of chance (happenstance —the occurrences which are the seeds of novelty) and necessity (lawful regularity which sifts and preserves the novelties thrown up by happenstance) lies at the root of all the fruitful history of the universe. The theologian must be prepared to reckon with this role of chance. Physical process is not merely mechanical but it has an inherent openness which makes this a world of true becoming.

The cosmologist, peering into the future as well as the past, sees that the universe will eventually end badly —either in the bang of cosmic collapse or in the whimper of cosmic decay. The theologian must be prepared to take on board the scientific certainty that humanity will only prove to be a transient episode in the history of the universe.

There are many ways in which science speaks to theology in a manner to which that subject must be prepared to pay attention. I certainly want to take science seriously, but I want to take the unity of knowledge and the rich diversity of reality, even more seriously. It is my firm belief that science and theology are both aspects of a rational inquiry into the way the world is. To deny that and to confine oneself to science alone would be to embrace the impoverished fallacy of scientism.

I have tried to draw attention in this section to certain aspects of science which seem to one to be relevant to that wider quest for knowledge and understanding. In the following section I shall try to explore the cousinly relationship between science and theology by paying attention to what it means to take theology seriously. I shall suggest that there is a significant degree of parallelism between the endeavour of science and that of theology. It is a common contention amongst scientists turned theologian, that their former and their latter disciplines are really intellectual cousins under the skin (cf. Barbour, 1990; Peacocke, 1984; Polkinghorne, 1991, chs. 1 and 2).

II. On the Endeavour of Theology

1. Theology is Concerned with a Rational Exploration of What is the Case. Many people have a picture of theologians as being concerned with irrational assertion, putting a stop to critical inquiry by evoking the unchallengeable concept of “revelation.” In the United Kingdom, politicians use the adjective “theological” in a pejorative sense, denoting mysterious and ill-founded claims. I want to say as strongly as I can that such an understanding of the theological enterprise is a travesty of it.

Religious belief is not a question of shutting one's eyes, gritting one's teeth and believing the impossible. Faith involves an act of commitment, but that commitment is motivated; it is a leap into the light and not into the dark. Revelation is not some mysterious unquestionable propositional knowledge which is made available in an ineffable manner. The word is properly used of those persons and experiences which are particularly transparent to the presence of God, and of the record of those divine encounters. Of course God is always present, just as the laws of nature are always acting, but in the same way that there are particularly contrived circumstances (which we call experiments) in which the character of natural law can most readily be discerned, so there have been seminal religious experiences through which God has been most readily perceived. For the Christian, the focus of divine self-disclosure has been in the history of Israel and in the person of Jesus Christ, and what gives the Bible its unique importance and authority is its witness to these events.

The significance of the specific is much higher in theology than in science. Because of the impersonal character of its material (the world as “it”), science is usually able to repeat its phenomena under controllable conditions. That is not always so —cosmology must rest content with the one universe of our observable experience-but the historical sciences tend to lean heavily on the experimental sciences for their interpretative power. Theology is concerned with the personal and indeed, with transpersonal divine Reality (the world as “thou”). In such a realm of experience, the unique has an indispensable role. It is by no means inconceivable that the fullest knowledge of God was in the possession of a wandering carpenter in a peripheral province of the Roman Empire, far away and long ago.

It is the essence of a rational inquiry to conform its method to the intrinsic nature of the reality encountered. In our investigation of the physical world we possess the wonderful power of experiment to interrogate that world at will. Once we enter the realm of the personal, testing must give way to trusting. If I am always setting little traps to see if you are my friend I shall, by those very actions, destroy the possibility of real friendship between us. It is a fundamental fact of the spiritual life that “you shall not put the Lord your God to the test.” In consequence, there is less unanimity of conclusion to be obtained in these personal matters, as we all know when we compare our judgments of other people's character. What appears generosity to one will seem a spendthrift act to another. Yet these difficulties should not deter us from the delicate but essential task of seeking truth about people and about God.

I belong to the Anglican tradition which has always believed its theological thinking to require a tripod base: scripture, tradition, and reason. Scripture has an indispensable normative role because, as I have already said, it records the foundational experiences through which we believe God has made himself most clearly known. Our knowledge of Jesus Christ as an historical figure is virtually entirely dependent on the documents of the New Testament. Yet those documents are not just plain, matter-of-fact accounts. They are already interpreted. In theology, as in science, we approach experiences from a point of view, wearing those “spectacles behind the eyes.” That view is not incorrigibly fixed. It can undergo development and correction in the light of continuing experience and further reflection. This is the role of tradition, the record of the insights of the worshipping and believing community. Religion is not something “out there,” for our detached intellectual perusal alone. It touches all of what we are and therefore it must be pursued within a community of relationships. Yet that community is not just engaged in a social conspiracy to see it that way. Like the scientific community, the Church is concerned with truth and in its pursuit it must be prepared to employ critical reason, the third leg of my theological tripod. As part of that use of reason, theology will need to pay respect to what all other forms of inquiry can tell it about the way things are. Included in that is the need to pay attention to science, whose insights will impose conditions of consonance which theology must take into account. The tone of the theological discourse about creation has certainly been affected by the realization that the physical world as we know it did not spring into being, ready made, a few thousand years ago, but it has had a long evolving history.

One of my favourite quotations is from a 20th century Canadian Jesuit, Bernard Lonergan (1904-1984). He worked in the great theological tradition stemming from St. Thomas Aquinas, which sees all search for truth as ultimately the search for God, whether he is known by name or not. Lonergan wrote “God is the unrestricted act of understanding, the eternal rapture glimpsed in every Archimedean cry of Eureka.” (cf. Lonergan, 1957, p. 684). That is the true spirit of theology, and one most congenial to a scientist.

2. The Physical World Testifies to the Logos. In the previous section I drew attention to the rational beauty, and transparency to our investigation, which is so remarkable a feature disclosed to science in its deeper explorations of the universe. One could interpret the “unreasonable effectiveness” of mathematics in acting as the key to an understanding of the physical world by saying that that world is shot through with signs of mind. To the religious believer that is indeed the case, for it is the Mind of God which is revealed in that wonderful order.

That insight would be an example of theology's ability to answer meta-questions, arising from science but going beyond the latter's self-limited power. My instinct as a scientist is to seek an understanding through and through. That thirst for understanding will not be quenched by science alone. If we are to explain why the reason of our minds so perfectly fits the rational structure of the world, it is likely that the clue will be found in some deeper rationality which embraces both. The rational will of the Creator provides just such an explanation. I do not present that as a knock-down case for theism. I do not believe that there are any strict proofs either of God's existence or of his non-existence. But I do present it as an intellectually satisfying insight. I would not claim that atheism is unjudicious, merely that it is less comprehensive in its explanatory grasp than is belief in God, and less intellectually satisfying.

Arguments of this kind have a very long history. In the ancient world they were often expressed in terms of the Logos —much more than word, something like a divine rational order. St. John's gospel, in its famous prologue, speaks of the Word “through whom all things were made and without whom was not anything made that was made.” (Jn 1,3) St. Augustine found that very familiar but he encountered something entirely new when John went on to make the astonishing Christian claim that “the Word was made flesh and dwelt among us.” I will return to that claim later.

3. The World is a Fruitful Creation Endowed with Freedom, Allowing God’s Providence Acting within an Open Future. Theology answers the meta-question arising from the insights of the Anthropic Principle by interpreting the “fine-tuning” of physical law and circumstance as the fertile endowments given to his universe by a Creator who wills it to be such as to be capable of a fruitful history. Indeed we do not live in “any old world,” but in a creation.

So far, so good, but theology has also to reckon with the way in which that potential fertility is made actual. At every stage of cosmic or terrestrial history it is through the interplay of two opposing tendencies, which in a shorthand sort of way we might call “chance and necessity.” By chance I mean just “happenstance,” the actual way things turn out to be. There happens to be a genetic mutation which then produces a new possibility for the form life takes. These novel offerings of chance would, however, have no lasting significance if they were not sifted and preserved in a lawfully regular environment. That is what I mean by necessity. Natural selection would not work unless the environmental conditions were relatively stable and the transmission of genetic information from one generation to the next were not reasonably reliable. For creativity, the physical world must neither be too rigid nor too sloppy.

The problem here for theology is to know what to make of the role of chance, with its implication that the history of evolution is contingent and not the unfolding of an inevitable master plan. To some biologists, such as Jacques Monod and Richard Dawkins, the role of chance has meant that ultimately the universe is a tale told by an idiot. A favourite adjective for conveying this message is to call chance “blind.”

There is no unique way of going from science to metaphysics and there is an alternative interpretation available which is more congenial to the religious thinker. It emphasizes in a more even-handed way the twin roles of chance and necessity. The God of love will endow his creation with an appropriate measure of freedom. He cannot exert the unrelaxing grip of a Cosmic Tyrant, but rather he must allow the other truly to be itself. The contingencies of chance are then seen to be reflections of this gift; an evolutionary universe is a creation allowed by its Creator to explore and realize its own God-given potential. But God is not only loving; he is also faithful. His eternal reliability will find its reflection in the regularity (but not rigidity) of natural law, which makes its indispensable contribution to cosmic fruitfulness. That is how a theologian might read the significance of the interplay of chance and necessity.

It is a very important theological concept to recognize that creation involves God in a voluntary “self-limitation” as he graciously allows something other than himself to have a genuine life of its own. The gift of Love must be the gift of a due independence. This insight affords some modest help with the greatest of all theological perplexities: the problem of suffering and evil. It is surely better to have a world of freely-choosing beings than a world of totally programmed automata. Yet the necessary cost of the former is the allowing of these free beings to make wrong moral choices. This is in essence the so-called “free-will defence” in relation to moral evil (the chosen cruelties of human kind). I have pointed out elsewhere (cf. Polkinghorne, 1989, ch. 5) that this needs augmentation by a “free-process defence” in relation to physical evil (disease and disaster). Austin Farrer once asked, what was God 's will in the dreadful disaster of the Lisbon earthquake, which killed 50,000 people in one day in 1755? His answer, hard but true, was that the elements of the earth's crust should behave in accordance with their nature. They have their due independence also. I believe that God neither wills the act of a murderer nor the incidence of a cancer, but he allows both to happen in a world to which he has given its creaturely independence.

One might say that it is one thing to claim value in allowing moral beings to exercise free choice, but what is the value in allowing tectonic plates to slip? I think that the answer is probably that only a universe which is subject to the free-process defence could be one that could give rise to beings subject to the free-will defence. We have emerged in the history of the physical universe and although our self consciousness means that we transcend our origins, yet we are still closely linked in character to the physical world that gave us birth. Its openness is the ground of our freedom.

20th century physics has seen the death of mere mechanism. I indicated in the previous section that quantum theory and chaotic dynamics both suggest that we live in a world of true becoming. The future is not rigidly determined but its form is contained within certain limits of possibility. Which of these possibilities is actually realized will then depend upon the action of further causal principles which I believe take the form of something like “active information.” In this way I picture a possible eventual understanding (still very remote in any detail) of how the mental and the material relate to each other, how my intention of raising my hand is translated into the act of its raising. If this is the right way in which to think about human agency, I think it is also the way in which we can think of divine providential agency as well. The physical world is very much more clouds than clocks and I imagine God's guiding hand to be at work within the cloudiness of unpredictable open physical process. If that is the case, two things follow. One is that God's action will always be hidden. It will not be demonstrable by experiment, though it may be discernible by faith. The other is that God's providence is conceived as acting within the grain of natural process, not against it. That is to be expected theologically, since the laws of nature are not constraints acting independently of God himself but rather they are expressions of his will. He cannot act against himself.

Christian theology has to steer a middle course between two unacceptable extremes. God is not a Cosmic Tyrant, who keeps all that happens within his tight control alone. We have already seen that the idea of the gift of creaturely independence is essential if we are to find any answer to the problems of theodicy. Yet God is not to be pictured as a Deistic Spectator either, simply watching all that happens in indifferent or impotent detachment. In the 18th century, deism flourished because the clockwork picture of the physical world then in vogue seemed to leave God with no other role to fulfil. We are delivered from that theological inanity today.

4. Theology will often Challenge our Common Sense Assumptions. We saw above (see I, n. 4) that the physical world often behaves in regimes remote from everyday experience, in ways which are counterintuitive to our expectations. If science is often surprising, we may expect that theology will be the more so. Clearly the Infinite is going to elude the grasp of our finite minds. Hence the warnings of apophatic theology that it is easier to say what God is not, than what he is. The symbol of Sinai, where God is to be found in clouds and thick darkness, is a powerful and necessary one.

We have to avoid the extreme of cutting down God to our human size, but equally we must avoid the other extreme of a facile invocation of mystery as a lazy substitute for the rigours of theological thought. Paradox is only to be embraced when it is forced upon us by experience. Here the lesson from science is clear and helpful. 19th century physics established the wave nature of light but the work of Planck and Einstein in the early years of this century also made it clear that in certain circumstances light behaved as if composed of particles. No progress would have been made by denying either half of this apparently irreconcilable behaviour. For many years physicists had to cling to experience without being sure how to make sense of it. Eventually, the discovery of quantum field theory provided an understanding of this strange behaviour.

It has been the testimony of the Church from the earliest times that its experience of Christ cannot be contained within human language alone but it is driven to use divine titles for him and to pay him worship. It is profoundly perplexing how the infinity of God and the finiteness of human nature can both be focused on a single figure, but if that is the form reality is found to take (as I believe it is), then the rational response is to wrestle with the paradox and not to dismiss it by a truncated account, reduced to everyday terms alone.

5. The Insights of Theology are Exciting. I have already begun to speak of the Incarnation, that quintessential Christian ascription of both human and divine status to Jesus Christ. It is a deeply exciting concept that the God who is in so many ways ineffable and beyond human power to grasp, should have acted to make himself known in the plainest possible terms by living the life of a man. There is a deep human longing to know what God is like, to discover what is the nature of Ultimate Reality. As a Christian I believe that disclosure has been made in Jesus Christ. Equally exciting is the idea that by sharing in the life of humanity, God in Christ has redeemed that life from its manifest limitation and distortion by sin and that Jesus's resurrection is the ground of the hope of a destiny beyond death in which we all will share. “As in Adam all die, even so in Christ shall all be made alive” (1Cor 15:22). Within the confines of this contribution I cannot explore these great themes any further, defending their rationality and explaining why I believe in their truth. All I can say is that the possibility that these things might be so is surely the most important matter that we could ever be called upon to investigate.

Another satisfying insight of theology is the way in which it can tie together the diverse layers of our multi-valued experience. The physical world, whose rational order is revealed to us by science, is also the carrier of beauty, the arena of moral decision and the place of religious encounter. It is both significant and puzzling that there is their variety in our experience. The religious believer can perceive the divine unity which underlies and unites this polyvalent diversity: science is exploring the rational order of creation; our aesthetic pleasures are a sharing in God's joy in that creation; our moral intuitions are intimations of his will; our religious experience is the true meeting with him.

6. Yet Theology is Problematic. It would be disingenuous not to recognize that there are difficulties in accepting a religious account of reality. I want briefly to address the two which I think hold more people back from belief than any others and which are continuing perplexities for those of us who take our stand in the community of faith.

The first is, of course, the problem of evil and suffering. I do not need to elaborate it; we are all only too aware of it. Does a world with the Holocaust and famine really look like the creation of a loving and almighty God? I have already mentioned the free-will defence and the free-process defence as some kind of philosophical response to these problems. While I think there is some help to be had there, I would not wish to pretend that I believe there is some facile way in which evil and suffering can be explained away. The mystery they represent lies much deeper than can be touched by cerebral argument alone. One of the central reasons why I am a Christian is because I believe Christianity does meet the problem of suffering at the most profound level.

The Christian God is not a spectator of suffering, looking down in compassion upon the strange world that he has made. Rather, he is a fellow-participant in the bitter history of pain and diminishment. The Christian believes that in the cross of Christ, in the darkness and dereliction of Calvary, we see God himself stretching out his arms to embrace the suffering of the world. He accepts being impaled upon the contradictions of creation and by that acceptance he offers us the hope of a victory over those contradictions. It is a profoundly mysterious and profoundly moving insight that the Christian God is the Crucified God.

The second great problem for religious belief lies in its diversity. If you were to stop a suitable person in the street in Oxford or Delhi or Tokyo and ask them what matter is made of, in each of those cities you would receive the same answer: quarks and gluons and electrons. There is a universality of agreement in science which is very impressive and it has proved to be exportable throughout the world. If you were to stop three people in the street in those three cities and ask them the religious question of what is the nature of Ultimate Reality, the chances are that you would receive three very different answers. What are we to make of the variety and stability of the world's great religious traditions and their incompatibility with each other? Does it not encourage the view that science deals with a public world of fact whilst religion is concerned with a private world of opinion? We may respect each other's religious opinions but are they more than “true for me” or “true for you”, rather than being plain “true,” pure and simple?

I am not really interested in things which are just true for me. My quest is for truth, not just a congenial manner of speaking. How then can I understand this problem of the variety of religious belief? I want to say three things. The first is that I believe each tradition contains truth about its encounter with a divine reality. God has not left himself without witness in any age or place. The traditions do not all say the same thing but they are clearly all concerned with the same spiritual dimension of human experience. The second thing is that because the infinite God must veil his presence from finite beings, the divine light will always be refracted by the cultural prisms of human kind. Here is some kind of clue to the phenomenon of diversity, though I cannot claim that I believe it explains the whole of that diversity. The third thing I want to say is that, whatever respect I rightly accord to my friends in other traditions, I must hold firm, persistently but humbly, to my Christian belief that God has made himself uniquely known in Jesus Christ. Many puzzles remain. I think that the inter-relationship of the world's religions is one of the most urgent and most difficult theological problems that we face today.

7. Theology has Things to say to Science. Religion cannot dictate the scientific programme of investigation nor prescribe what the results of those investigations will be. There is a due autonomy on the part of science which theology must respect. Yet that does not mean that there are not insights from theology which will complement and complete the insights of a science whose success stems, partly at least, from the self-restricted modesty of its ambitions. There are many questions which are meaningful to ask and necessary to address, with which science is powerless to deal. Some of these are those meta-questions, such as the significance of the deep intelligibility of the physical world and of its finely-tuned anthropic fruitfulness, which we have already considered. Because theology aims to speak of God it must have things to say which are relevant to all that is, for nothing exists except by God's will. In that sense theology is still the Queen of Sciences, not because it can lord it over other forms of rational inquiry but because it can take the results of those inquiries and embed them in the most profound and comprehensive matrix of understanding. However satisfying science can be, its impersonal approach will never touch more than the periphery of our human experience. All those things which touch us in our inner being lie beyond its grasp. Deep within us is an intuition of hope and human significance, despite the manifest transience of life in this world. Is there a purpose at work in the history of the universe? Is something really happening in what is going on? Is there a destiny awaiting us beyond our death? These are religious questions and the search for their answers is part of the quest for truth. I believe that science and theology are both to be taken with the utmost seriousness and that they are cousinly partners in that necessary search for the fullest possible understanding.