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John Polkinghorne, KBE, FRS, is fellow and retired president of Queens’ College, Cambridge. Winner of the 2002 Templeton Prize, he is both a quantum physicist and an Anglican priest.

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Exploring Reality

Yale University Press

Contents

Preface..........................................................................ixAcknowledgements.................................................................xviiCHAPTER ONE: Reality?............................................................1CHAPTER TWO: The Causal Nexus of the World.......................................7CHAPTER THREE: Human Nature: The Evolutionary Context............................38CHAPTER FOUR: The Historical Jesus...............................................60CHAPTER FIVE: Divine Reality: The Trinity........................................90CHAPTER SIX: The Nature of Time: Unfolding Story.................................113CHAPTER SEVEN: The Spirit and the Faiths.........................................127CHAPTER EIGHT: Evil..............................................................136CHAPTER NINE: Ethical Exploration: Genetics......................................147CHAPTER TEN: Imaginative Postscript: Some Nave Speculations.....................169Index............................................................................179

Chapter One

For some the title of this book will be a red rag to a bull. They will dismiss it as exhibiting the author's naivety. 'Reality', and the closely-allied word 'truth', are not in common currency in some circles today, and consequently those who employ them lay themselves open to intellectual condescension and pity. I am unrepentant.

Much of the tone of contemporary sceptical discourse was already set by those nineteenth-century Masters of Suspicion, Friedrich Nietzsche and Sigmund Freud. The former once referred to truths as illusions that we have forgotten are illusions, and the latter, through his work in human psychology, suggested that the actual motivations for our beliefs often lie hidden in unconscious depths, so that they are frequently quite different from those which our conscious egos propose to us. Of course, each of these thinkers implicitly exempted their own ideas from subversion along the lines of their particular critiques, as also did Karl Marx in relation to the influence of economic factors and social class.

More recently, the extreme wing of the movement loosely categorised as postmodernism has suggested that instead of truth about reality, we have to settle for a portfolio of opinions expressing personal or societal points of view. Though there may appear to be conflicts between the different perspectives proposed, it is said that there is no real competition because, in fact, there is not actually anything to contend about. All points of view can claim equal authenticity, since none is constrained by an independently accessible external reality. The story goes that intellectual life is strictly la carte.

Science has not been exempt from this assault on the possibility of rationally conclusive discourse. Its findings are held simply to be the products of the communities that propose them; its theorisings are supposed to be more about the exercise of power than about the attainment of veracity. For the extreme postmodernist, there are not really quarks and gluons as the constituents of matter, but the idea of them is a construct of the invisible college of physicists, who have simply colluded in seeing the world in a quarklike way.

As with many other reductive and dismissive accounts of human activity and human nature, these critiques are based at best on no more than quarter truths, whose scope is then exaggerated in the attempt to promote them into the pretension of total explanation. Of course, the motivations for human beliefs do lie at a variety of levels within the psyche, an insight known to Augustine and to generations of spiritual directors. Of course, scientific activity is influenced by cultural and social judgements of what investigations it would be valuable to pursue and viable to fund. Of course, experience has to be interpreted before it becomes truly interesting, and this introduces the danger of distortion through tricks of perspective, a problem that has to be recognised and taken into account. A naive objectivity of unproblematic 'facts' is far too crude a way to encapsulate our encounter with the way things are. Yet few critics of the ideas of truth and reality are so committed to that cause that it is matter of indifference to them what kind of doctor, witch or medical, they consult when they are ill. Nor do they tend to regard belief in the safe functioning of the aircraft they are about to board as being sufficiently established if it has arisen simply as the result of a socially negotiated consensus. At the beginning of the twentieth century, the positivist philosopher-physicist Ernst Mach denied the existence of atoms. Can any one really believe today that matter does not have an atomised structure? Scientific knowledge of a reliable kind really does increase. Of course, we know now that atoms themselves are made out of still smaller constituents (quarks, gluons and electrons). The maps that science makes of the physical world have always had to be open to revision when territory comes to be surveyed on a more intimate scale than had been explored hitherto. Yet these maps have proved reliable and trustworthy at the level of detail that they profess to describe. Science's achievement is not absolute truth, but it can rightly claim verisimilitude.

The realist counter-claim that is being made against the sceptics-a claim that certainly requires detailed defence-is that of a critical realism. The adjective is necessary because something more subtle than naive objectivity is involved (we do not see quarks directly, but their existence is indirectly inferred). The noun is justified because the best explanation of persistent scientific explanatory power and technological success is that science succeeds in describing, within the acknowledged limits of verisimilitude, the way things actually are.

Almost all scientists, consciously or unconsciously, are critical realists. Scientist-theologians are often self-confessed critical realists about both science and theology. I have written rather often on the subject, seeking to base the argument on case studies, since I do not believe that it can be settled solely by abstract considerations. I do not intend to repeat that discussion here. Let me be content to make three simple points:

(1) Defence of realism in science depends partly upon recognising the unexpected character often stubbornly displayed by nature. Far from its behaving like epistemological clay in our pattern-seeking hands, capable of being moulded into any pleasing shape that takes the fancy, the physical world frequently proves highly surprising, resisting our expectations and forcing us to extend, in unanticipated ways, the range of our intellectual understanding. In consequence, the feel of actually doing science is undeniably one of discovery, rather than pleasing construction. Theologians can claim something similar about the encounter with God. Time and again human pictures of deity prove to be idols that are shattered under the impact of divine reality.

(2) An experience fundamental to the pursuit of science is a sense of wonder, induced by the beautiful order and fruitful nature of the universe. There is an authenticity about science's discoveries of explanatory insight that is deeply persuasive that the scientists are 'onto something', gaining knowledge that comes from an external reality and which cannot be conceived as being simply an internally spun fable. Albert Einstein used often to express his awe at the order of nature, saying that he felt a mere child in the presence of the elders when confronted by such intellectual beauty. From deep simplicity comes immense complexity. For example, the genetic code, lying at the basis of all terrestrial life, depends upon certain chemical properties of the nucleotides forming DNA and RNA, which properties are themselves consequences of the outworking of the laws of electromagnetism and quantum theory. In a suitably compact notation, I could literally write the latter on the back of an envelope. No human ingenuity could be believed to be capable of constructing independently a story of such astonishing economy and fruitfulness. Its discovery required the genuine nudge of nature. The religious believer can find here grounds for understanding the universe as a creation, whose deep order and inherent fertility express the mind and will of its Creator.

(3) If interpreted experience is to be the basis of our understanding reality, then our concept of the nature of reality must be sufficiently extensive to be able to accommodate the richness of our experience. The many-levelled character of human encounter with the world resists all attempts to reduce it to a narrow account. In chapter 3 I shall discuss the context within which human life has evolved and is now lived and I shall argue that a just discussion requires recognition not only of the physico-biological environment, but also of the realms of truth, beauty and goodness. There is an authenticity and richness in human life that demands that we take all of our experience with the utmost seriousness, respecting the multidimensional way in which it presents itself to us.

Any metaphysical world view that did not seek to take reality on reality's terms in the way that I have briefly sketched would be unacceptable. I want to use this short book to suggest some thoughts that arise from using trinitarian theology as a way of engaging with reality in the richness and variety of its actual impact upon us, resisting the temptation to embrace prematurely tidy schemes produced by those false reductions which, though they may sound speciously plausible in the abstraction of the study, deny the full authenticity of actual human experience, lived in the world.

Chapter Two

Science achieves such frequent success in the many areas of its enquiry that it is difficult for us to remember how diverse are those areas and, in many ways, how little understood are the connections between them. Most scientists necessarily spend much of their time concentrating on their own specialised disciplines. Consequently, they seldom raise their eyes to look at the broader scene. Were they to do so, they would behold a fragmented picture, a patchwork of areas of insight only loosely, if at all, connected to each other.

One way of dividing up the scientific account is to introduce a hierarchy of forms of rational enquiry, ordered according to an ascending scale of the complexity of the entities under discussion. Proceeding in this way yields the canonical sequence: physics, chemistry, molecular biology, cellular biology, biology of organisms, neuroscience, psychology, anthropology, sociology. Sub-sequences are readily identified within these levels of description. For example, in the case of physics there is a spectrum of internal complexity running from elementary particle physics to theories of condensed matter and continuum mechanics. The levels overlap to some degree (superconductors are surely more complicated than simple inorganic molecules, so physics and chemistry are not cleanly separated from each other) and the relationship between successive scientific levels can sometimes be a matter of uncertainty and dispute. While all would acknowledge that biochemistry throws very significant light on processes taking place within living entities, the complex character of even a single cell is such that it is by no means clear that a constituent account tells us all that we shall ever need to know about the richly complicated and integrated character of living entities. Francis Crick proclaimed that 'The ultimate aim of the modern movement in biology is in fact to explain all biology in terms of physics and chemistry', but whether this ambitious programme is feasible or well conceived is open to very serious question.

Those who think like Crick are strong reductionists. For them, science's technique of splitting entities into constituent parts is not simply a convenient methodological strategy for tackling certain problems, but it also corresponds to the ontological character of nature itself. In their opinion, the constituent picture is simply the fundamental way things are, so that the true account of reality lies solely at the lowest level, with the other levels in the hierarchy of complexity being just complex corollaries of what lies beneath. Logically this should lead these reductionists to accord the palm to elementary particle physics, and there are certainly some people in my old subject who are bombastic enough to entitle its still-unfulfilled quest for a Grand Unified Theory, the search for a 'Theory of Everything'. Yet strong reductionists often display a reluctance to sink below the level of their own discipline, so that geneticists want to attach special significance to genes, and molecular biologists to molecules.

Against the strong reductionists are the emergentists, whose slogan is 'More is different'. For them the whole exceeds the sum of its parts, so that it would be absurdly inappropriate to call a constituent account a Theory of Everything. They point to the degree of conceptual independence that exists between the various levels of the hierarchy of sciences. It is clear that the fitness of an organism for survival in an ecological setting is not an idea that can usefully be transcribed into statements about collections of quarks, gluons and electrons. The critical question remains, however, How different is more? Is it simply that the novel properties manifested by complex entities require an extended range of concepts for their effective description, or is it the case that emergence is even more interesting than that, in that what is involved requires an enhanced understanding of the causal variety of the world?

The point at issue can be illustrated by considering the wetness of water. This is not a property possessed by a single specimen of [H.sub.2]O, but it is an emergent effect due to the readjustments of the distribution of energy brought about by bringing together a very large aggregation of water molecules. Rather than attempting the impossible task of calculating the mutual interactions of, say, more than 10 molecules, it is convenient to introduce the notion of surface tension in order to think about the behaviour of drops of water. Yet we have every reason to believe that surface tension is simply the macroscopic expression of the consequences of all those microscopic molecular interactions. No causal property of a novel kind is thought to be at work beyond the cumulative effect of intermolecular forces. This kind of phenomenon can be thought of as being weak emergence. Metaphysically it is an unproblematic idea, however difficult it may be to unravel scientifically the detail of particular instances.

Strong emergence would correspond to the case in which a new causal principle becomes active in a complex system, of a distinct kind not encountered at lower levels of complexity. More would then be different in a radical way. An example of strong emergence would be if it is indeed the case that human persons possess the power of free agency and are able to act in the world to bring about their choices in a fashion that is not simply an immensely complicated addition of the causal properties of the elementary particles that make up their bodies.

(The question of what degree of freedom humans enjoy in the exercise of agency has, of course, been a matter of longstanding philosophical controversy. Strong emergence would correspond to the so-called liberty of indifference, in which a person makes a choice between genuinely open possibilities, rather than to the liberty of spontaneity, in which actions accord with wishes, but both deed and desire could together be subject to an all-encompassing determination arising from the lowest physical level. The point at issue concerns the status of what philosophers call an incompatibilist account of human freedom, the claim that true personal liberty cannot be reconciled with total physical determinism in the behaviour of constituents. I must confess to being an incompatibilist.)

Is strong emergence of this irreducible kind a conceivable possibility, given what science can tell us about the causal nexus of the world? If the scientific account presented us with a single causal web of known and determinating character, smoothly interpolating between the behaviour of entities encountered at all levels of scientific enquiry but deriving solely from the properties of basic constituents, then the answer would seem to be No. Causality certainly looks like a zero-sum game, and if the causes operating at one level are totally adequate to determine all that happens, the reduction to that level, though doubtless practically infeasible, would surely be ontologically correct. (That is why I am an incompatibilist.) However, the patchwork character of scientific understanding implies that it is by no means certain that such a seamless web of basic causality is the right way to think about science's account of the process of the world. The point can be illustrated from within physics itself before going on to consider the matter in greater generality.

(Continues...)

Excerpted from Exploring Realityby JOHN POLKINGHORNE Copyright © 2005 by Yale University. Excerpted by permission.
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