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The Trinity and an Entangled World

William B. Eerdmans Publishing Company

Chapter One

John Polkinghorne

The minimal form of relationality is simple juxtaposition. Grains of sand simply lie beside each other on the seashore. Not much significance attaches to mere contiguity, though a pile of sand can acquire a relational property when its height reaches a tipping point, at which the addition of a few more grains will trigger a sand-slide. Chemists call mere aggregates "mixtures." Greater significance attaches to "compounds," where forces between the constituents bind them together in a union that endures unless some sufficient exterior influence breaks it apart. The dance of life in a biological cell involves a much more complex and dynamic relationality, sustained by continual interactions between enzymes and proteins in processes of great intricacy. Multicellular life exemplifies yet more complex relationships, as different kinds of cells perform different functions that are essential to the continued life of the organism. In higher animals, activities such as defense of the herd, grooming, and the sharing of food establish a kind of social relationality. Human persons are not simply individual egos, but they are partly constituted by a rich network of interpersonal relationships. Trinitarian theology speaks of Father, Son, and Holy Spirit united in one Godhead by the unique relationship of perichoresis, the mutual interpenetration and exchange of love between the divine Persons. Considerations of this kind suggest a metaphysical picture of reality as a Great Chain of Being, of which the successive links are levels of increasingly profound relationality, expressed in different ways according to the natures of the entities involved.

Developments that have taken place in physical science in the last century have strikingly confirmed this intuition of the fundamental character of relationality. The entities that physics investigates are much less complex than those that are the concern of biology and anthropology, let alone theology's concern with the infinite reality of God. Yet discoveries have been made and insights gained in physical science that have clearly indicated the need not to rely simply on atomistic accounts and reductive techniques of analysis, but to employ also a complementary approach characterized by holism and intrinsic relationality.

In the past, the methodology of physics was largely reductionist. Its motto was "Divide and rule." The motive for this strategy was the pragmatic pursuit of understanding sought in the most readily accessible way, since it is much easier to try to understand bits and pieces than it is to understand entities in their complex totalities. There is no doubt that much success has come to physics through following this approach. An elementary particle physicist like myself has to assert that the unveiling of the quark level in the structure of matter was an important advance, but this should not lead to the boastful claim, sometimes made by particle physicists, that constituent accounts of this kind are the true "Theory of Everything." Even within physics itself this is manifestly false. Using quantum chromodynamics (the theory of quarks) is not the way to tackle the task of understanding the turbulent motion of fluids. In the words of Philip Anderson, a Nobel Prize winner for his work in condensed matter physics, "More is different." Reductionist theories may be methodologically effective for some purposes, but they are far from being epistemologically or ontologically adequate.

The atomic approach fathered by Democritus might have seemed to have found its fullest expression in the eighteenth century, with the post-Newtonian conception of a mechanistic physics, picturing the world as made up of a collection of small particles colliding with each other as they moved in the container of space and in the course of the unfolding of universal time. Despite the mysterious interaction at a distance postulated for gravity, the dominant concept of interactive relationship held in the eighteenth century was through contact. Some pictured atoms as small balls with hooks attached, which might engage with other hooks on other atoms to form a linked system. This picture rose only slightly above the level of mere juxtaposition. Yet reality fights back against such reductive oversimplification. The conceptual world of modern physics is quite different, being altogether more interconnected and relational in its character. A number of developments have brought about the demise of a merely mechanical atomism.

Relationality in Modern Physics

Particles and Fields

Newton's concept of gravitational attraction at a distance, so successful in bringing interrelated order into an account of the solar system, had nevertheless been troubling to him. The character of gravity seemed mysterious, transcending anything capable of being conceived of in terms of contact forces between atoms. Some influence apparently pervaded space far beyond the bodies that were considered to be its source. In the nineteenth century, the development of electromagnetic field theory through the insights of Michael Faraday and James Clerk Maxwell led eventually to the idea of the ether as an all-pervading medium filling the "container" of space. This picture already represented a significant modification of the idea of physical reality as being composed of an assemblage of localized and isolatable units. However, classical fields, though they are spread out through space and vary in time, nevertheless are local entities in a causal sense. What happens in the neighborhood of a point can be altered without inducing immediate changes elsewhere, so even fields can be considered bit by bit. In classical physics, fields are fully determinate entities, described by partial differential equations whose solutions are as well defined as those of the ordinary differential equations that describe particles. Relativity theory abolished the idea of the ether as the carrier of the fields and concentrated on the fields themselves as being fully physical entities, possessing energy and momentum just as material particles do.

Quantum fields, whose properties were first discovered by Paul Dirac, exhibit both wavelike properties (because of their spacetime extension) and also particlelike properties (because their energy comes in discrete packets). Particles and fields are concepts that are fused in contemporary physics. Modern thinking pictures an entity such as an electron as being an excitation in the universal electron field, a concept that subtly modifies a purely atomized notion of electron nature. This field theory idea neatly explains why all electrons manifest exactly the same properties. They are related by their common origin in the electron field.

Quantum theory was also found to imply that collections of electrons are not simply ensembles of juxtaposed individuals, but the presence of many electrons imposes a restraint on the dynamical states available to each individual electron. This collective character of modern physical thinking is expressed in the concept of the "statistics" that govern the behavior of collections of identical particles. Two different kinds of constraint are possible. If the particles obey what is called fermi statistics, as is the case for electrons, then no two particles can ever occupy the same state of motion. The resulting "exclusion principle," implying that the presence of an electron in a state closes it to other electrons, lies at the basis of atomic structure and the form of the periodic table of chemistry, and so it plays a fundamental role in determining the structure of matter and enabling the processes of life. If the particles obey what is called bose statistics, then the reverse collective behavior applies. Bosons display a propensity to aggregate in the same state. Photons, the particles of light, are bosons and their consequent herd instinct is the basis of the laser. In the case of either form of statistics, the possible behavior of an individual particle is related to the state of its cousins.

Space and Time

Albert Einstein's great discoveries of special and general relativity abolished the Newtonian picture of the container nature of absolute space and the flow of an absolute time, totally distinct from each other and simply providing the setting for the motion of atoms. Relativity theory provided instead a consolidated account, intimately linking space, time, and matter in a single package-deal. Matter curves spacetime, and this curvature in its turn influences the paths of matter, in a way that produces the effect we call gravitation. Space and time are no longer the given setting, unchanging in its character, providing the stage on which the material actors of the cosmic drama perform their parts, but there is a dynamic and unfolding interaction between them all.

This integrated theory made it possible to attempt the construction of a model of the physical universe itself, providing the first opportunity for the formulation of a truly scientific cosmology. The intimate relational character of the universe thus constituted, constrained the nature of what could be supposed about its history and structure. In his initial attempt at a cosmology, Einstein, influenced by a preference as old as Aristotle for the concept of an everlasting universe, had thought it necessary to modify his equations in order to permit a static solution. He later described this as the greatest blunder of his life. He had missed the chance to find the time-varying solutions of the original equations, discovered independently by the Russian meteorologist Alexander Friedmann and the Belgian priest Georges Lemaître, that described an expanding universe of the kind that the observations of Edwin Hubble would subsequently confirm to be the case.

Unified Theories

From one point of view, modern physics has been the tale of the search for ever greater unification of the fundamental properties of nature. The process started with Galileo's assertion, contrary to Aristotle, that terrestrial and celestial matter were the same. In the nineteenth century, the experimental discoveries of Hans Christian Oersted and Michael Faraday, and the deep theoretical insight of James Clerk Maxwell, led to the unification of what had seemed to be two quite different classes of phenomena, electricity and magnetism. In the 1960s, Steven Weinberg and Abdus Salam independently found a way to combine electromagnetism with the weak nuclear interactions responsible for radioactive phenomena such as β-decay, uniting them in a single account. This was a synthesis that on the face of it might have seemed highly unlikely, since the two interactions have very different strengths and the weak interactions display a chirality (a preference for left-handed configurations) that is not present in electromagnetism. Nevertheless it turned out that there was a deep relational structure that bound the two sets of phenomena together.

Since then there has been a vigorous quest for a way to draw the strong nuclear forces and gravity into the greater synthesis of a Grand Unified Theory (GUT), a search that has been encouraged by the way in which the extrapolation of present effects into the realms of ultra-high energy that would have been operative at the epoch immediately following the big bang seems to indicate that all these forces would then have been of comparable strengths. So far, speculative ideas of this kind have not proved wholly successful, or commanded universal acceptance, though many regard superstring theory as a promising contemporary candidate for this unificatory role. Whatever reservations some physicists may have about particular proposals, most nevertheless entertain the expectation that there is indeed some form of GUT underlying the superficial diversity of the forces of nature, a hope that may be seen as expressing a deep intuitive conviction that there is a coherent unified structure expressed in the relationships of the physical world.

Nonlocalizability

Einstein had been one of the grandfathers of quantum theory, but he had come to detest his grandchild. He felt that its cloudy fitfulness threatened the reality of the physical world, in whose character he wanted there to be an unproblematic objectivity. Consequently he sought to discover properties of quantum theory that, he believed, would demonstrate its incompleteness. As part of this program Einstein, together with two young collaborators, Boris Podolsky and Nathan Rosen, showed that once two quantum entities had interacted with each other, the theory implied that they remained coupled together to the extent that a measurement made on one of them would have immediate consequences for the other, however far it had moved away since the interaction. In other words, quantum theory implied nonlocality, a togetherness-in-separation, of a counterintuitive kind. Einstein himself felt that this effect was so "spooky" that it showed there must be something in need of correction in quantum thinking. Yet, long after Einstein's death there came ample experimental confirmation of the mutual entanglement present in quantum processes (the "EPR effect"). Quantum entities can be found in states where effectively they behave as a single system, so that acting on one has an instantaneous effect on the others (see the contributions of Jeffrey Bub and Anton Zeilinger). Physical reality fights back against a crass reductionism. It is not possible to describe the world of subatomic physics atomistically! Nature is intrinsically relational.

Two comments need to be made on this remarkable phenomenon. The first is to emphasize that its character is ontological and not merely epistemological. There is, of course, nothing surprising in the fact that knowledge acquired here can also have implications for some distant state of affairs. If an urn contains two balls, one white and one black, and we both take out a ball in our clenched fists, if subsequently I open my hand and see the white ball, then I immediately know that you have the black ball, even if you are now miles away. This was always the case and all that has happened is that I am now aware that it is so. The EPR effect is different. Whatever is measured here has an immediate causal effect, bringing about a new state of affairs elsewhere. It is as if, were I to find a red ball, then you would find you have a blue one, but if I had found a green ball, then your ball would have become yellow. The second point is that this EPR effect, though it acts instantaneously, does not violate special relativity. The latter forbids the communication of information faster than the velocity of light, but analysis shows that the EPR process cannot be used for the immediate transmission of the details of the state of affairs from one point to another point. Quantum entanglement is a subtle form of interrelationality.

Modern physics has also discovered limitations on the isolatability previously assumed to be present at the macroscopic level in classical Newtonian physics. These restrictions arise in a way quite different to the case of quantum theory. The systems described by chaos theory display an extreme sensitivity to the minutest detail of their circumstance, and this implies such a degree of vulnerability to external disturbance that they cannot properly be considered in isolation from their environment. The so-called "butterfly effect" gives vivid expression to this insight. When the Earth's weather system is in a chaotic mode, a butterfly stirring the air with its wings in the African jungle today could cause a disturbance capable of growing exponentially till it resulted in a storm over Europe in three to four weeks time. Not only is detailed long-term weather forecasting never going to be possible, but it is clear that the interrelationship of meteorological events is subtle and extensive.

Thus the separability of entities from each other that seems to be so apparent a part of our everyday experience, and which is needed by science for the possibility of successfully contained experimentation (since otherwise one would have to take everything into account before being able to investigate anything), is far from being unproblematic. The older style of scientific thinking started with isolated systems and then asked how they might be conceived to interact with each other. We now see that this is too simplified an account, which needs supplementation by an adequate recognition that holistic effects are also active in the physical world. What all this implies for physics and for metaphysics is still far from being well worked out, but it is clear that atomism has to give way to some intrinsically more relational form of the structure of physical reality.

(Continues...)

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Excerpted from The Trinity and an Entangled World Copyright © 2010 by Wm. B. Eerdmans Publishing Co.. Excerpted by permission of William B. Eerdmans Publishing Company. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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