Chapter 4: Physics and Metaphysics

Religion in an Age of Science
by Ian Barbour

Chapter 4: Physics and Metaphysics

In part 2 we turn from the methods of science to the content of particular scientific theories. In successive chapters we look at three scientific disciplines: physics, astronomy, and evolutionary biology. In each case, current scientific theories are outlined and their philosophical and theological implications are explored.

Physics is the study of the basic structures and processes of change in matter and energy. Dealing with the lowest organizational levels, and using the most exact mathematical equations, it seems of all sciences furthest removed from the concerns of religion for life, mind, and human existence. But physics is of great historical and contemporary importance because it was the first science that was systematic and exact, and many of its assumptions were taken over by other sciences. Its methods were seen as ideals for other sciences to emulate. It exerted a major influence on philosophy and theology.

Moreover, though physicists study only the inanimate, they look today at entities from a variety of domains, from quarks and atoms to solid state crystals, planets, and galaxies -- including the physical basis of living organisms. Already in the field of physics we confront issues of the observer and the observed, chance and law, and parts and wholes. But the issues here are inevitably complex, and readers who find the details difficult to follow can find a summary of the conclusions at the end of the chapter.

Three assumptions of Newtonian physics have been called into question in the twentieth century:

1. Newtonian epistemology was realistic. Theories were believed to describe the world as it is in itself, apart from the observer. Space and time were held to be absolute frameworks in which every event is located, independently of the frame of reference of the observer. The "primary" qualities, such as mass and velocity, which can be expressed mathematically, were considered objective characteristics of the real world.

2. Newtonian physics was deterministic. In principle, it was held, the future of any system of matter in motion could be predicted from accurate knowledge of its present state. The universe, from the smallest particle to the most distant planet, seemed to be governed by the same inexorable laws.

3. The Newtonian outlook was reductionistic in holding that the behavior of the smallest parts, the constituent particles, determines the behavior of the whole. Change consists in the rearrangement of the parts, which themselves remain unchanged. Here was a powerful image of nature as a law-abiding machine, an image that strongly influenced the development of science and Western thought. This view of the world as a clockwork mechanism led to the deistic view of god as the clockmaker who designed the mechanism and left it to run itself.

The eighteenth century saw the further elaboration of Newtonian mechanics. In the nineteenth century, new types of conceptual schemes were introduced in physics, including electromagnetic theory and the kinetic theory of gases. But the basic assumptions remained unchanged. All laws seemed to be derivable, if not from the mechanics of particles, at least from the laws governing a few kinds of particles and fields. In kinetic theory and thermodynamics, the behavior of gases was described in terms of probability, but this procedure was considered to be only a convenience in calculation. It was assumed that the motion of all gas molecules is precisely determined by mechanical laws, but because these motions are too complex to calculate, we can use statistical laws to predict the average behavior of large groups of molecules.

All three of these assumptions -- realism, determinism, and reductionism -- have been challenged by twentieth-century physics. The changes in concepts and assumptions were so great that it is not surprising that Kuhn uses it as a prime example of a scientific revolution, a paradigm shift. We will examine quantum theory and relativity as well as recent work in thermodynamics and then explore their implications for religious thought.

I. Quantum Theory

We have seen that particle models, such as the billiard ball model, dominated the classical physics of matter. By the nineteenth century, theorists used another basic type of model, that of waves in continuous media, to account for a different group of phenomena involving light and electromagnetism. But early in the present century a number of puzzling experiments seemed to call for the use of both wave and particle models for both types of phenomena. On the one hand, Einstein’s equations for the photoelectric effect and Compton’s work on photon scattering showed that light travels in discrete packets, with definite energy and momentum, behaving very much like a stream of particles. Conversely, electrons, which had always been viewed as particles, showed the spread-out interference effects characteristic of waves. Waves are continuous and extended, and they interact in terms of phase; particles are discontinuous, localized, and they interact in terms of momentum. There seems to be no way to combine them into one unified model.1

Suppose, for example, that a stream of electrons is sent through two parallel slits in a metal screen and strikes a photographic film placed a few centimeters behind the screen. Each electron registers as a single tiny dot on the film; it seems to arrive as a particle, and it must presumably have gone through either one slit or the other if the charge and mass of the electron are indivisible. Yet the dots on the film fall in an interference pattern of parallel bands, which can be explained only if one assumes a wave passing through both slits. This same wave-particle duality is found throughout atomic physics. But a unified mathematical formalism can be developed that allows the observed events to be predicted statistically. It yields wave functions for a mixture of possibilities, a "superposition of states." One can calculate the probability that an electron will strike the film at any given point. Within the calculated probability distribution, however, the exact point at which a particular electron will strike cannot be predicted.

Similarly, no unified model of the atom has been developed in quantum theory. The earlier "Bohr model" of the atom could be easily visualized; particlelike electrons followed orbits around the nucleus, resembling a miniature solar system. But the atom of quantum theory cannot be pictured at all. One might try to imagine patterns of probability waves filling the space around the nucleus like the vibrations of a three-dimensional symphony of musical tones of incredible complexity, but the analogy would not help us much. The atom is inaccessible to direct observation and unimaginable in terms of sensory qualities; it cannot even be described coherently in terms of classical concepts such as space, time, and causality. The behavior of the very small is radically different from that of everyday objects. We can describe by statistical equations what happens in experiments, but we cannot ascribe familiar classical attributes consistently to the inhabitants of the atomic world.

The extensions of quantum theory in recent years into the nuclear and subnuclear domains have maintained the probabilistic character of the earlier theory. Quantum field theory is a generalization of quantum theory that is consistent with special relativity. It has been applied with great success to electromagnetic interactions and subnuclear interactions (quantum chromodynamics or quark theory) and electroweak theory.2 Let us trace, then, the challenge that quantum theory presents in turn to realism, determinism, and reductionism.

1. Complementarity

Niels Bohr defended the use of wave and particle models and other pairs of sharply contrasting sets of concepts. His discussion of what he called the Complementarity Principle included several themes. Bohr emphasized that we must always talk about an atomic system in relation to an experimental arrangement; we can never talk about it in isolation, in itself. We must consider the interaction between subject and object in every experiment. No sharp line can be drawn between the process of observation and what is observed. We are actors and not merely spectators, and we choose the experimental tools we will employ. Bohr held that it is the interactive process of observation, not the mind or consciousness of the observer, that must be taken into account.

Another theme in Bohr’s writing is the conceptual limitation of human understanding. The human as knower, rather than as experimenter, is the center of attention here. Bohr shares Kant’s skepticism about the possibility of knowing the world in itself. If we try, as it were, to force nature into certain conceptual molds, we preclude the full use of other molds. Thus we must choose between complete causal or spatiotemporal descriptions, between wave or particle models, between accurate knowledge of position or momentum. The more one set of concepts is used, the less the complementary set can be applied simultaneously. This reciprocal limitation occurs because the atomic world cannot be described in terms of the concepts of classical physics and observable phenomena.5

How, then, are the concepts of quantum physics related to the real world? Three differing views of the status of theoretical entities in science yield differing interpretations of quantum theory.

1. Classical Realism. Newton and almost all physicists through the nineteenth century said that theories are descriptions of nature as it is in itself apart from the observer. Space, time, mass, and other "primary qualities" are properties of all real objects. Conceptual models are replicas of the world that enable us to visualize the unobservable structure of the world in familiar classical terms. Einstein continued this tradition, insisting that a full description of an atomic system requires specifying the classical spatiotemporal variables that define its state objectively and unambiguously. He held that since quantum theory does not do this, it is incomplete and will eventually be superseded by a theory that fulfills classical expectations.

2. Instrumentalism. Here theories are said to be convenient human constructs, calculating devices for correlating observations and making predictions. They are also practical tools for achieving technical control. They are to be judged by their usefulness in fulfilling these goals, not by their correspondence to reality (which is inaccessible to us). Models are imaginative fictions used temporarily to construct theories, after which they can be discarded; they are not literal representations of the world. We cannot say anything about the atom between our observations, though we can use the quantum equations to make predictions about observable phenomena.

It is often assumed that Bohr must have been an instrumentalist because he rejected classical realism in his protracted debate with Einstein. He did indeed say that classical concepts cannot be used unambiguously to describe independently existing atomic systems. Classical concepts can be used only to describe observable phenomena in particular experimental situations. We cannot visualize the world as it is in itself apart from our interaction with it. Bohr did agree with much of the instrumentalist critique of classical realism, but he did not endorse instrumentalism specifically, and more careful analysis suggests that he adopted a third alternative.

3. Critical Realism. Critical realists view theories as partial representations of limited aspects of the world as it interacts with us. Theories allow us to correlate diverse aspects of the world manifest in differing experimental situations. To the critical realist, models are abstract and selective but indispensable attempts to imagine the structures of the world that give rise to these interactions. The goal of science, in this view, is understanding, not control. The corroboration of predictions is one test for valid understanding, but prediction is not in itself a goal of science.

A good case can be made that Bohr adopted a form of critical realism, though his writings were not always clear. In the debate with Einstein, he was not denying the reality of electrons or atoms, only that they are the sort of things that admit of precise classical space-time descriptions. He did not accept Mach’s phenomenalism, which questioned the reality of atoms. Summarizing the dispute, Henry Folse says, "He discarded the classical framework and kept a realistic understanding of the scientific description of nature. What he rejects is not realism, but the classical version of it."4

Bohr presupposed the reality of the atomic system that is interacting with the observing system. In contrast to subjectivist interpretations of quantum theory, which take observation to be a mental-physical interaction, Bohr talks about physical interactions between instrumental and atomic systems in a total experimental situation. Moreover, wave and particle or momentum and position or other complementary descriptions apply to the same object, even though the concepts are not unambiguously applicable to it. They represent different manifestations of the same atomic system. Folse writes:

Bohr argues that such representations are ‘abstractions’ which serve an indispensable role in allowing a phenomenon to be described as an interaction between observing systems and atomic systems, but which cannot picture the properties of an independent reality. . . . We can describe such a reality in terms of its power to produce the various different interactions described by the theory as providing complementary evidence about the same object.5

Bohr did not accept the classical realist view of the world as consisting of entities with determinate classical properties, but he still held that there is a real world, which in interacting has the power to produce observable phenomena. Folse concludes his book on Bohr with this summary:

The ontology implied by this interpretation of Bohr’s message characterizes physical objects through their powers to appear in different phenomenal manifestations rather than through determinate properties corresponding to those of phenomenal objects as was held in the classical framework. The case is then made that, within the framework of complementarity, it is possible to preserve a realistic understanding of science and accept the completeness of quantum theory only by revising our understanding 0f the nature of an independent physical reality and how we can have knowledge of it.6

In short, we do have to abandon the sharp separation of the observer and the observed that was assumed in classical physics. In quantum theory, the observer is always a participant. We will find a similar epistemological lesson in relativity. In complementarity, the use of one model limits the use of other models. Models are symbolic representations of aspects of interactive reality that cannot be uniquely visualized in terms of analogies with everyday experience; they are only very indirectly related to either the atomic world or the observable phenomena. But we do not have to accept an instrumentalism that makes theories and models useful intellectual and practical tools that tell us nothing about the world.

Bohr himself proposed that the idea of complementarity could be extended to other phenomena susceptible to analysis by two kinds of models: mechanistic and organic models in biology, behavioristic and introspective models in psychology, models of free will and determinism in philosophy, or of divine justice and divine love in theology. Some authors go further and speak of the complementarity of science and religion. Thus C. A. Coulson, after explaining the wave-particle duality and Bohr’s generalization of it, calls science and religion "complementary accounts of one reality."7

I am dubious about such extended usage of the term. I would set down several conditions for applying the concept of complementarity.8

1. Models should be called complementary only if they refer to the same entity and are of the same logical type. Wave and particle are models of a single entity (for example, an electron) in a single situation (for example, a two-slit experiment); they are on the same logical level and had previously been employed in the same discipline. These conditions do not apply to science and religion." They do not refer to the same entity. They arise typically in differing situations and serve differing functions in human life.9 For these reasons I speak of science and religion as alternative languages and restrict the term complementary to models of the same logical type within a given language, such as personal and impersonal models of God (chap. 2).

2. One should make clear that the use of the term outside physics is analogical and not inferential. There must be independent evidence of the value of two alternative models or sets of constructs in the other field. It cannot be assumed that methods found useful in physics will be fruitful in other disciplines.

3. Complementarity provides no justification for an uncritical acceptance of dichotomies. It cannot be used to avoid dealing with inconsistencies or to veto the search for unity. The paradoxical element in the wave-particle duality should not be overemphasized. We do not say that an electron is both a wave and a particle, but only that it exhibits wavelike and particlelike behavior; moreover we do have a unified mathematical formalism, which provides for at least probabilistic predictions. We cannot rule out the search for new unifying models, even though previous attempts have not yielded any theories in better agreement with the data than quantum theory. Coherence remains an important ideal in all reflective inquiry, even if it is qualified by acknowledgment of the limitations of human language and thought.

2. Indeterminacy

We have seen that for individual events quantum theory typically makes only predictions of probability. For example, we can predict when half of a large group of radioactive atoms will have disintegrated, but we cannot predict when a particular atom will disintegrate; we can predict only the probability that it will disintegrate in a given time interval. The Heisenberg Uncertainty Principle states that the more accurately we determine the position of an electron, the less accurately we can determine its momentum, and vice versa. A similar uncertainty relation connects other pairs of conjugate variables, such as energy and time.

Do these uncertainties represent the limitations of our knowledge or real indeterminancy and chance in the world? Three possible answers were given in the early years of quantum theory, and the debate among them continues today:

1. Uncertainty may be attributed to temporary human ignorance. Exact laws will eventually be discovered.

2. Uncertainty may be attributed to inherent experimental or conceptual limitations. The atom in itself is forever inaccessible to us.

3. Uncertainty may be attributed to indeterminacy in nature. There are alternative potentialities in the atomic world.

The three positions parallel the three epistemological positions of the preceding section. The first is classically realist (in epistemology) and deterministic (in metaphysics). The second is instrumentalist and agnostic about determinism; we can never know how the atom itself behaves between observations. The third, which I defend, is critically realist and indeterministic. Let us look at each of these interpretations.10

1. Uncertainty as Human Ignorance

Some of our uncertainties reflect our lack of knowledge about systems that conform to precise laws. Kinetic theory assumed that the motion of gas molecules is precisely determined but is too complicated to calculate. The uncertainty was thought to be entirely subjective, representing incompleteness of information. A minority of physicists, including Einstein and Planck, have maintained that the uncertainties of quantum mechanics are similarly attributable to our present ignorance. They believed that detailed subatomic mechanisms are rigidly causal and deterministic; someday the laws of these mechanisms will be found and exact prediction will be possible.

Einstein wrote, "The great initial success of quantum theory cannot convert me to believe in that fundamental game of dice. . . . I am absolutely convinced that one will eventually arrive at a theory in which the objects connected by laws are not probabilities but conceived facts."11 Einstein expressed his own faith in the order and predictability of the universe, which he thought would be marred by any element of chance. "God does not play dice," he said. As we saw, Einstein was a classical realist, holding that the concepts of classical physics must "refer to things which claim real existence independent of perceiving subjects."

David Bohm has tried to preserve determinism and realism by constructing a new formalism with hidden variables at a lower level. The apparent randomness at the atomic level would arise from variations in the concurrence of exact forces at the postulated subatomic level.12 So far his calculations yield no empirical conclusions differing from those of quantum mechanics, though Bohm hopes that in the future hidden variables may play a detectable role. Most scientists are dubious about such proposals. In the absence of any clear experimental evidence, the defense of determinism rests largely on philosophical grounds. Unless someone can actually develop an alternative theory that can be tested, they say, we had better accept the probabilistic theories we have and give up our nostalgia for the certainties of the past.

2. Uncertainty as Experimental or Conceptual Limitations

Many physicists assert that uncertainty is not a product of temporary ignorance but a fundamental limitation permanently preventing exact knowledge of the atomic domain. The first version of this position, found in the early writings of Bohr and Heisenberg, claims that the difficulty is an experimental one; the uncertainty is introduced by the process of observation. Suppose that we want to observe an electron. To do so we must bombard it with a quantum of light, which disturbs the situation we were attempting to study. The disturbance of the system is unavoidable, since there must be at least a minimal interaction of the observer and the observed. Although this interpretation fits many experiments, it appears unable to account for uncertainties when nothing is done to disturb the system -- for example, the unpredictability of the time at which a radioactive atom spontaneously disintegrates or the time at which an isolated atom makes a transition from an excited state.

The second version of the argument attributes uncertainty to our inescapable conceptual limitations. By our choice of experimental situations we decide in which of our conceptual schemes (wave or particle, exact position or exact velocity) an electron will manifest itself to us. The structure of the atomic world is such that we must choose either causal descriptions (using probability functions that evolve deterministically) or spatiotemporal descriptions (using localized variables that are only statistically connected) -- but we cannot have both at once. This interpretation is agnostic as to whether the atom itself, which we can never know, is determinate or indeterminate (though a particular author expounding it may on other grounds favor one assumption or the other). As indicated above, many physicists since Bohr have been instrumentalists, though I have claimed that he himself was closer to critical realism.

3. Uncertainty as Indeterminacy in Nature

In his later writings, Heisenberg held that indeterminacy is an objective feature of nature and not a limitation of human knowledge.13 Such a viewpoint would accord with the critical realism I have advocated in which scientific theories are held to be representations of nature, albeit limited and imperfect ones. These limitations help to remind us that the denizens of the atomic realm are of a very different sort from the objects of everyday experience -- but this does not mean that they are less real. Instead of assuming that an electron has a precise position and velocity that are unknown to us, we should conclude that it is not the sort of entity that always has such properties. Observing consists in extracting from the existing probability distribution one of the many possibilities it contains. The influence of the observer, in this view, does not consist in disturbing a previously precise though unknown value, but in forcing one of the many existing potentialities to be actualized. The observer’s activity becomes part of the history of the atomic event, but it is an objective history, and even the spontaneously disintegrating atom, left to itself, has its history.

If this interpretation is correct, indeterminacy characterizes the world. Heisenberg calls this "the restoration of the concept of potentiality." In the Middle Ages the idea of potentiality referred to the tendency of an entity to develop in a particular way. Heisenberg does not accept the Aristotelian manner of describing a potentiality as a striving to attain a future purpose, but he does suggest that the probabilities of modern physics refer to tendencies in nature that include a range of possibilities. The future is not simply unknown. It is "not decided." More than one alternative is open and there is some opportunity for unpredictable novelty. Time involves a unique historicity and unrepeatability; the world would not repeat its course if it were restored to a former state, for at each point a different event from among the potentialities might be actualized. Potentiality and chance are objective and not merely subjective phenomena.

A more exotic version of objective indeterminacy is Hugh Everett’s many-universes interpretation. Everett proposed that every time a quantum system can yield more than one possible outcome, the universe splits into many separate universes, in each of which one of these possible outcomes occurs.14 We happen to be in the universe in which there occurs the outcome that we observe, and we have no access to the other universes in which duplicates of us observe other possibilities. Since there are many atoms and many quantum events each second, the universe would have to divide into a mind-boggling proliferation of universes. Moreover, the theory seems to be in principle untestable, since we have no access to other universes containing the potentialities unrealized in ours. It seems much simpler to assume that potentialities not actualized in our universe are not actualized anywhere. Then we would have one universe which is objectively indeterminate.

In any case, adherents of the second and third of these basic positions -- which between them include by far the majority of contemporary physicists -- agree in rejecting the determinism of Newtonian physics, even if they do not agree on their reasons for doing so.

3. Parts and Wholes

Beyond the challenges to realism and determinism, quantum theory calls into question the reductionism of classical physics. We have already discussed the inseparability of observer and observed and the need to consider both the experimental apparatus and the atomic system. But the necessity of talking about wholes is also evident in many other ways.

It was once thought that protons, neutrons, and electrons were indivisible, the basic building blocks of matter. During the 1950s and 1960s, experiments with high-energy accelerators produced a variety of other types of particles, each with distinctive mass, charge, and spin, some existing for only a billionth of a second or less. Systematic order within this zoo of strange particles appeared when it was proposed in 1963 that they are all composed of even smaller particles dubbed quarks. There seem to be only a few types of quarks (arbitrarily identified by "flavors" and "colors") and a few simple rules for the ways they can combine. But quarks are a strange type of "component": free quarks have never been observed, and it appears that a quark cannot exist alone, according to the theory of quark confinement. A proton is made up of three quarks, for example, but if you try to separate them you need a great deal of energy and you end by creating more quarks, which combine with the ones you already had to make new protons and other particles. Quarks are parts that apparently cannot exist except in a larger whole.15

The various "elementary particles" composed of quarks, seem to be temporary manifestations of shifting patterns of waves that combine at one point, dissolve again, and recombine elsewhere. A particle begins to look more like a local outcropping of a continuous substratum of vibratory energy. A force between two particles (protons, for example) can be thought of as arising from a field or from a rapid exchange of other kinds of particles (mesons, in this case). A bound electron in an atom has to be considered as a state of the whole atom rather than as a separate entity. As more complex systems are built up, new properties appear that were not foreshadowed-in the parts alone. New wholes have distinctive principles of organization as systems and therefore exhibit properties and activities not found in their components.

Consider the helium atom, composed of two protons and two neutrons (in its nucleus) and two orbital electrons. In the planetary model it was pictured as a nucleus around which circled two separate identifiable electrons; the atom’s parts were clearly distinguishable, and the laws of its total behavior were derivable from analysis of the behavior of these components. But in quantum theory the helium atom is a total pattern with no distinguishable parts. Its wave function is not at all the sum of two separate single-electron wave functions. The electrons have lost their individuality; we do not have electron A and electron B but simply a two-electron pattern in which all separate identity is lost. (In the statistics of classical physics, an atom with A in an excited energy state and B in a normal state counts as a different configuration from the atom with A and B interchanged, but in quantum theory it does not.)

In the case of helium and more complex atoms with additional electrons, we find that their configurations are governed by the Pauli Exclusion Principle, a law concerning the total atom that cannot conceivably be derived from laws concerning individual electrons. The principle states that in a given atom no two electrons can be in identical states (with the same quantum numbers specifying energy, angular momentum, and spin). To this remarkable and far-reaching principle can be attributed the periodic table and the chemical properties of the elements. When another electron is added to a given atom, it must assume a state different from all electrons already present. If one used classical reasoning, one would have to assume that the new electron is somehow influenced by all the other electrons; but this "exclusion" does not resemble any imaginable set of forces or fields. In quantum reasoning any attempt to describe the behavior of the constituent electrons is simply abandoned; the properties of the atom as a whole are analyzed by new laws unrelated to those governing its separate "parts," which have now lost their identity. A bound electron is a state of the system, not an independent entity.16

The energy levels of an array of atoms in the solid state (such as a crystal lattice) are a property of the whole system rather than of its components. Again, some of the disorder-order transitions and the so-called cooperative phenomena have proved impossible to analyze atomistically -- for example, the cooperation of elementary magnetic units when a metal is cooled or the cooperative behavior of electrons in a superconductor. Such situations, writes one physicist, "involve a new organizing principle as we proceed from the individual to the system," which results in "qualitatively new phenomena." There seem to be system laws that cannot be derived from the laws of the components; distinctive explanatory concepts characterize higher organizational levels.17 Interpenetrating fields and integrated totalities replace self-contained, externally related particles as fundamental images of nature. The being of any entity is constituted by its relationships and its participation in more inclusive patterns. Without such holistic quantum phenomena we would not have chemical properties, transistors, superconductors, nuclear power, or indeed life itself. Such holism contrasts with the reductionism of Newtonian physics.

4. Bell’s Theorem

Some recent experiments have thrown further light on the relation between the three classical assumptions -- realism, determinism, and reductionism. In 1935, Einstein, Podolsky, and Rosen (EPR) proposed a type of experiment that has become possible to carry out only in the last few years.18 In one version, a two-proton system splits up into two protons, A and B, which fly off in opposite directions, say left and right. If the system initially had total spin zero, conservation laws require that the spin of B is equal and opposite to that of A. The spin of A has an equal probability of being oriented in any direction. If a directionally sensitive detector is placed perpendicular to the flight path at some distance to the left, one can measure a particular component of the spin of A. One can then predict the precise value of the corresponding component of the spin of B (namely, equal and opposite), which can be measured with a second detector at the right.

Quantum theory describes each proton in flight as a mixture of waves, representing with equal probability various possible spin orientations. Each set of waves collapses to a single value only when a measurement is made. But B will behave differently according to what one chooses to measure on A. How can B know which component of A’s spin one will choose to measure? Einstein argued that while in flight B’s spin must already have had a definite value, not a probability distribution.

Einstein made two assumptions: (1) classical realism (individual particles possess definite classical properties at all times, even when we are not observing them), and (2) locality (no causal influence can be transmitted between two isolated systems faster than the speed of light, which we will see shortly is a limit set by relativity theory). Einstein concluded from his "thought experiment" that the probability descriptions of quantum theory must be incomplete, and that there must be hidden variables in each of the traveling particles, determining a particular outcome.

Bohr replied that Einstein’s form of realism was misguided because we cannot talk about the property of a particle except in relation to a measuring process. In particular, we must think of the two particles and the two detectors as a single indivisible experimental situation. The wave function encompasses both particles, even though they are distant from each other. We have seen that Bohr also asserted the inescapability of indeterminacy. Bohr and Einstein had protracted arguments over these and other proposed experiments, which strained their earlier friendship. Neither was able to convince the other.

In 1965 John Bell calculated the statistical correlation one would expect between the two detectors (as a function of their relative orientations) if Einstein’s assumptions are correct. Recent experiments by Alain Aspect and others (using photons rather than protons) have not been consistent with these expectations, indicating that one of Einstein’s assumptions is incorrect. ma "delayed choice" version of the experiment in 1983, Aspect was able to switch the orientation of the left detector at the last minute while the photons were in flight -- too late for any signal to reach the right photon before it arrived at its detector.19 The photons behaved as if there were some communication between them, but they were too far apart to communicate in the time available. Classically realistic local theories seem to be ruled out by these experiments.

Most physicists conclude that we should follow Bohr here, giving up classical realism and keeping locality (the finite limit on the speed with which any influence can be transmitted). They insist that particles A and B originated in one event and must be regarded as a single system even when they are far apart. The quantum wave function must include both particles. Only after an observation can they be regarded as having separate identities and independent existence. But it is possible to maintain a critical realism concerning the probabilistic whole while abandoning classical realism concerning the separate parts. Thus the physicist Paul Davies concludes, "The system of interest cannot be regarded as a collection of things, but as an indivisible, unified whole."20 Polkinghorne writes; "Quantum states exhibit an unexpected degree of togetherness. . . . The EPR experiment points to a surprisingly integrationist view of the relationship of systems which have once interacted with each other, however widely they may subsequently separate."21

Another option is to keep classical realism and give up locality. Among defenders of realistic nonlocal theories are Bell and David Bohm. We mentioned earlier Bohm’s idea that hidden variables could preserve determinism. He has developed the equations for a quantum potential that acts as a kind of instantaneous pilot wave guiding particles; statistical variations arise from fluctuations of hidden variables. The quantum potential incorporates encoded information about both local and distant events and does not fall off with distance. Bohm holds that there is a holistic underlying implicate order whose information unfolds into the explicate order of particular fields and particles. One analogy he uses is a TV signal with information enfolded in an electromagnetic wave, which the TV receiver unfolds as a visual image. Another analogy is a holographic photograph, of which every part has three-dimensional information about the whole object photographed. If you cut the hologram into small pieces, you can unfold the whole image by illuminating any piece of it with laser light. The scheme is deterministic because entities in the explicate order are not self-determining but are expressions of the underlying implicate order.22

Bohm’s scheme shows a dramatic wholeness by allowing for nonlocal, noncausal, instantaneous connections. Events separated in space and time are correlated because they are unfolded from the same implicate order, but there is no direct causal connection between them since one event does not itself influence another event. It is like two TV screens showing images of a moving object taken from different angles; the two images are correlated, but one image does not influence the other. The scheme does not violate the relativistic prohibition of signals faster than the speed of light, for there is no way to use it to send a signal from one detector to the other. (We can not control the orientation of particle A, which arrives at random. The statistical correlation only shows up in the later comparison of the records from the two detectors.)23

Most physicists acknowledge that Bohm’s view is consistent with these experiments, but they are reluctant to abandon Bohr’s view until there is experimental evidence against it. The development of quantum potential theory by Bohm and his coworkers may lead to distinctive testable predictions, but it has not done so to date.

In sum, Einstein’s classically realist, determinist, and local interpretation seems to be ruled out by the Aspect experiments. Bohm’s theory, with Its classical realism, determinism, and extreme nonlocal holism, cannot yet be experimentally distinguished from standard quantum theory. The instrumentalists claim that we cannot say anything about the world between observations and therefore questions about determinism and holism should be dismissed as meaningless. I have advocated a combination of critical realism, indeterminacy, and a more limited form of holism, and I have suggested that Bohr himself was closer to this view than to instrumentalism.

II. Relativity and Thermodynamics

Before examining the metaphysical implications of quantum theory, let us consider the other major revolution in twentieth-century physics, Einstein’s theory of relativity. We will then look briefly at nonequilibrium thermodynamics, which raises some interesting questions about the emergence of order from disorder.

1. Space, Time and, Matter

For Newton and throughout classical physics, space and time are separable and absolute. Space is like an empty container in which every object has a definite location. Time passes uniformly and universally, the same for all observers. The cosmos consists of the total of all such objects in space at the present moment, which is a simultaneous and shared "now." The length and mass of an object are unchanging, intrinsic, objective properties, independent of the observer. All of this is close to our everyday experience and common-sense assumptions, but it is challenged by relativity.

In 1905, at the age of twenty-six, Einstein wrote his first paper proposing special relativity. The search for symmetry in the equations for moving electromagnetic fields, along with the Michaelson-Morley experiments with light, led him to postulate the constancy of the velocity of light for all observers. This hypothesis had unexpected and far-reaching implications. Imagine that an observer at the middle of a moving railway train sends light signals, which reach the equidistant front and rear of the train at the same instant. For an observer on the ground, the signals travel different distances to the two ends (since the train moves while the signals are traveling); therefore if the signals travel at constant velocity in his framework they must arrive at different times. The two events are simultaneous in one frame of reference but not in the other. The effect would be very small with a train but would be large with a space rocket or a high-energy particle approaching the velocity of light.24

There is also a time dilation, which has been confirmed in many experiments. For example, a mu-meson has a lifetime of 2 microseconds. But if it is traveling at very high velocity in a circular orbit in an accelerator, its lifetime as measured on the ground will be much longer, and it will go around many more times than one would expect. Measurements of mass and length as well as time vary according to the frame of reference. The mass of a particle, such as the circulating meson, becomes much larger as its velocity relative to the measuring apparatus approaches the velocity of light. Lengths contract, so a moving object appears much shorter in the direction of motion (though from the moving object, it is the other objects that appear compressed). The theory also predicts the equivalence of mass and energy (E = mc2, confirmed in the atomic bomb explosion), and also the creation and annihilation of matter and antimatter (confirmed in the creation and mutual annihilation of electron-positron pairs).

Because there is no universal simultaneity and no common present separating past and future, the division between past and future will vary among observers. Some events, which are past for one observer, may still be future for other observers. However, for any two events that could be causally connected (a light signal could pass between them), the order of before and after is the same for all possible observers. No one could conclude that an effect preceded its cause. There is no way to influence the past or to change history. People could leave the earth on a spaceship in the year 2000, travel at high velocity for five years, and return to earth five years older to find themselves in the year 3000. But there is no way they can go back to the year 1000. ("Time travel" works only in one direction, so no one will face the science fiction question of what would happen if you went back and killed one of your ancestors.)

Space and time, then, are not independent but are united in a spacetime continuum. The spatial separation of two events varies according to the observer, and the temporal separation also varies, but the two variations are correlated in a definite way. Different observers "project" spatial and temporal dimensions of the four-dimensional spatiotemporal interval in different ways, but each can calculate what the other will be observing. There are rules for translating into equivalent relationships in another frame of reference.

In 1915, Einstein went on to develop the general theory of relativity, extending his earlier ideas to include gravity. He reasoned that an observer in a windowless elevator or spaceship cannot tell the effects of a gravitational field from the effects of accelerated motion. From this he concluded that the geometry of space is itself affected by matter. Gravity bends space, giving it a four-dimensional curvature (here the fourth dimension is spatial rather than temporal, and it is reflected in the altered geometry of three-dimensional space). As John Wheeler puts it, "Space tells matter how to move, and matter tells space how to curve."25 Dramatic confirmation was obtained in 1919, when it was observed during an eclipse that light rays from distant stars were slightly bent by the sun’s gravitational field. Time is also shrunk by gravity, and clocks slow down as they do from relative motion. In 1959, very accurate experiments at Harvard showed that a photon traveling from the basement of a building to the top floor changes its frequency slightly because of the difference in gravitational field.

One of the most striking conclusions from general relativity is that the universe may be finite, curved, and unbounded (that is, closed) rather than infinite (that is, open). If so, a person setting out from the earth into space in one direction would return eventually from the opposite direction. As we will see in the next chapter, it is not clear from present evidence whether there is sufficient matter in the universe for space to be closed rather than open. But what has been clear since Hubble’s red-shift measurements is that space itself is everywhere expanding. The present motion indicates the expansion of all parts of the universe from a common explosion 15 billion years ago. This was not the explosion of matter into a preexisting void, but the expansion of space itself.

2. The Status of Time

Let me first discuss three claims supposedly based on relativity that seem to me dubious.

1. "Time is illusory and events are determined." We can draw graphs showing time as if it were another spatial dimension. It is sometimes said that we can represent the cosmos as a static spatiotemporal block that different observers "project" as spatial and temporal dimensions in differing ways. Taken as a whole, the block does not ‘happen"; it just "is." In reply, I would insist that temporal change does occur in every frame of reference. We should speak of "the temporalization of space" rather than "the spatialization of time."26 Dynamic events, not unchanging substances, are now taken to constitute reality. It may appear deterministic to say that what is future for one observer is already past (and therefore "determined") for another observer. But this is not true for causally related events, among which futurity is shared. Special relativity and quantum theory have been combined in relativistic quantum theory, in which indeterminacies become determinate only with the passage of time.

2. "Reality is mental." Length, mass, velocity, and time, once thought to be objective, primary properties of objects in themselves, are now known to be relative to the observer. This has sometimes been taken as evidence that the human mind forms the reality of the world. But the "frame of reference of the observer" does not require a human mind. It might consist of clocks and meter sticks and measuring devices that could be recorded by an automatic camera. The mesons circulating in an accelerator are "observed" by Geiger counters connected to computer printouts. The lesson here is interconnectedness, not the pervasiveness of consciousness or mentality.

3. "Relativity supports relativism." Science is said to have shown that everything is relative and there are no absolutes, and this has been cited in support of moral and religious relativism. But the claim is dubious even in physics. Many absolutes have been given up (space, time, mass, and so forth), but there are new ones. The velocity of light is absolute, and the spacetime interval between two events is the same for all observers. Everyone carries their own clock and their own time zone, but the order of causally related events does not change. Moreover, Einstein took pains to show that while phenomena do vary among frames of reference, the laws of physics are invariant among them. There is a core of relationships which is not observer-dependent, though it is described from multiple points of view.27

In relativity there is greater diversity among observations than in classical physics, but there is an underlying unity. In the previous chapter, I asked whether there is any such underlying unity among diverse religious traditions, any invariants in religious experience, any equivalencies in translating from one tradition to another. In that context I sought a middle path between an unequivocal absolutism and a total relativism -- a path not unlike that in relativistic physics, though obviously not expressed in mathematical equations.

If we reject these three dubious claims, does relativity have other metaphysical implications that can be defended? Yes, it shows us a dynamic and interconnected universe. Space and time are inseparable, mass is a form of energy, and gravity and acceleration are indistinguishable. There is an interplay between the dynamics of matter and the form of space, a dialectic between temporal process and spatial geometry. Matter is, if you will, a wrinkle in the elastic matrix of spacetime. Instead of separate enduring things, externally related to each other, we have a unified flux of interacting events. Gravity and quantum theory have not yet been united, but physicists are currently working on such a supertheory in which electromagnetic, nuclear, and gravitational forces will be shown to be forms of one basic force. Along with this wholeness and interdependence, however, relativity introduces a new form of separateness and isolation. It takes time for connections to be effective, so we are momentarily alone in each present. There are some regions of space so distant that it take billions of years for a signal to reach us from them. We are isolated from most of the universe for incredibly long stretches of time.

Does relativity provide any analogies for talking about God? Perhaps it can help us to imagine God as omnipresent yet superspatial. Karl Heim speaks of God and selfhood as other "spaces" and "in another dimension." The same set of events can be differently ordered in different spaces. Spaces are concurrent frameworks with incommensurable dimensions; they permeate each other without boundaries.28 Heim is extending terms from relativity as analogies for religious thought, not making direct inferences from science.

A further question is raised by the fact that apparently there can be no physical communication faster than the velocity of light. Do we say that God has an array of local projects in isolated parts of the universe? Or is God timeless and eternal, transcending time as well as space? I suggest that God is omnipresent and, knows all events instantaneously. The limitation on the speed of transmission of physical signals between distant points would not apply, since God is immanent at all points and in all events. God is neither at rest nor in motion relative to other systems. We would have to assume that God influences an event in terms of the pattern of events relevant to its situation and its causal past, which, of course, is uniquely defined for all frames of reference.29

3. Order and Disorder

In classical and relativistic physics, all interactions are exactly reversible in time. If you are watching a film of colliding billiard balls, and the film is alternatively run forward and backward, you cannot tell which direction was the original, since both sets of motions obey the laws of mechanics. But in phenomena among large numbers of particles there is an irreversible change from order to disorder, which indicates the directionality of time. A bottle of perfume is opened and the scent fills the room; the molecules do not spontaneously return from the room to the bottle. A bomb explodes and scatters its fragments, dissipating heat to the surroundings; the reverse does not occur. Past and future are here clearly distinguishable.

The Second Law of Thermodynamics expresses this change: in every closed system there is an increase of entropy, which is a measure of disorder. A high-entropy disordered system has high probability (because there are many arrangements of the constituents by which it can be achieved) and low information content (since it appears random). An ordered system, by contrast, has lower entropy, lower probability, and higher information content. In closed systems, order and information are dissipated over time. On a cosmic scale this is referred to as the "running down" of the universe. Energy becomes less available as temperature differences come to an equilibrium.

Living systems have a high degree of order and information. They have a very low probability of occurring from the random assembly of their constituent atoms or molecules. How, then, could they have come into existence in evolutionary history? And how can a living system grow and maintain itself today? Living organisms do not violate the Second Law because they are open rather than closed systems. They receive a constant inflow of materials and energy from the environment, deriving primarily from the sun’s energy. An organism is a relatively stable self-maintaining system, an island of high local order drawing on the order of its wider environment. A local change in entropy is paid for by a change in entropy elsewhere. 30

In chapter 6 we will ask about the evolutionary origin of life. But already within physics we find some interesting examples of the emergence of higher levels of order in self-organizing systems. Most physical systems will return to the most probable, disordered, equilibrium state if disturbed from it. But sometimes, if they are unstable and far from equilibrium, a new level of collective order will appear and achieve a stable form. Ilya Prigogine won a Nobel Prize for his work on nonequilibrium thermodynamics. One of his examples is the appearance of a vortex in the turbulence of a flowing river. Again, complex patterns of convection cells are formed in the circulation of a fluid heated from below. In such cases a small fluctuation is amplified and leads to a new and more complex order, which resists further fluctuations and maintains itself with a throughput of energy from the environment. Sometimes there is a "bifurcation of paths" (for example, the convection cells can go clockwise or counterclockwise). The choice of paths seems to be the result of very small chance fluctuations.31

Prigogine has analyzed many inanimate self-organizing systems in which disorder at one level leads to order at a higher level, with new laws governing the behavior of structures showing new types of complexity. Randomness at one level leads to dynamic patterns at another level. In some cases the new order can be predicted by considering the average or statistical behavior of the myriad components. But in other cases, Prigogine shows, there are many possible outcomes, and no unique prediction can be made. Multiple divergent solutions arise from these nonlinear instabilities. The formation of such self-organizing, self-perpetuating systems at the molecular level was perhaps the first step in the emergence of life. As in quantum theory, there seems to be a complex interplay of law and chance; here, too, we must look at larger wholes and higher levels of organization and not just at the component parts. Once again, determinism and reduction are called into question.

III. Metaphysical Implications

In the last two decades a proliferation of claims has arisen alleging that physics has far-reaching metaphysical implications. Some authors claim that quantum physics has demonstrated the mental character of reality. Quantum indeterminacy is also said to be compatible with life, human freedom, and God’s action, as Newtonian determinism was not. Other authors have delineated parallels between contemporary physics and Eastern mysticism.

1. The Role of Mind

Associated with physics has been a long tradition of philosophical idealism, the belief that reality is essentially mental in character. The Pythagoreans held that mathematical relationships are the underlying reality of nature. The Platonists took nature to be an imperfect reflection of another realm of perfect eternal forms. Both these themes were expressed in the writings of Kepler and Copernicus at the dawn of modern science. In the eighteenth century, Kant and his successors held that the structures of time, space, and causality are categories of human thought, which we impose on nature; we can never know things as they are in themselves.

New versions of idealism have claimed support from modern physics. Writing in the 1930s, James Jeans said, "The universe begins to look more like a great thought than like a great machine. Mind no longer appears as an accidental intruder in the realm of matter."32 Arthur Eddington assigned the determinative influence in all knowledge to the human mind. He pictures us following footsteps in the sand, only to discover that the tracks are our own. We impose our own patterns of law so that "the mind may be regarded as regaining from Nature that which the mind has put into Nature."33 In relativity, all the basic properties of objects, such as length, time, and mass, are relative to the observer. This has sometimes been cited as evidence of the priority of mind over matter, though as indicated earlier I am critical of this claim.

In quantum physics, the connection between theory and experiment is very indirect. Instrumentalists stressed the experimental side, arguing that theories are only useful fictions for correlating observations. But other scientists, focusing on the theoretical concepts, which are abstract and mathematical, found encouragement for idealistic interpretations. One major problem is the act of measurement, in which the multiple potentialities of an atomic system become one actuality. Physicists have been puzzled by the sharp discontinuity that occurs when the wave function (the "superposition of states" representing alternative outcomes) collapses to the one value that is observed. Along the route between the microsystem and the human observer, where does the initially indeterminate result get fixed? Bohr held that it is fixed when the system is large enough that the interaction is irreversible, namely when the measuring apparatus is affected. As experimenters we choose the apparatus, and this, too, influences the outcome. But critics pointed out that the apparatus is made up of atoms; in principle we could write a gigantic wave equation to describe both the apparatus and the microsystem. What would collapse that wave function?

The physicist Eugene Wigner holds that quantum results are fixed only when they enter somebody’s consciousness. "It is not possible to formulate the laws in a fully consistent way without reference to consciousness."34 He maintains that the distinctive feature of human consciousness, which causes the wave function to collapse, is introspection or self-reference; consciousness can give an account of its own state, cutting the chain of statistical coordinations. But why then do two different observers agree on the result of a quantum experiment?

Another physicist, John Wheeler, asserts that this is an observer-created universe. The collapse of the wave function is the product of intersubjective agreement in which the key feature is not consciousness but communication. He argues that the past has existence until it is recorded in the present. He tells the story of a conversation among three baseball umpires. One says, "I calls ‘em as I see ‘em." The second claims, "I calls em as they really are." The third replies, "They ain’t nothin’ until I calls em." As observers of the Big Bang and the early universe, says Wheeler, we have helped to create those events. Before there were observers, atoms were only partially individuated; they had enough reality to enter chemical reactions but were not fully real until they were later observed. He grants that it seems an anomaly that the present could influence the past, but he says that, in the quantum world of indeterminacy and acausality, ideas of before and after are meaningless. The past has no meaning unless it exists as a record in the present. So human beings are central in a participatory and observer-dependent universe.35

I do not find these interpretations of quantum physics convincing. Surely it is not mind as such that affects observations, but the process of interaction between the detection apparatus and the microsystem. The experimental results might be automatically recorded on film or on a computer printout, which no one looks at for a year. How could looking at the film or printout alter an experiment that has been recorded for a year? The Wheeler view seems very strange, for observers of the Big Bang are themselves products of the evolution of the cosmos, which included billions of years when there was no human consciousness and no observers. This is an unambiguous before and after in evolutionary history, and atoms that affect subsequent evolutionary events must surely be considered fully real.

The Bell’s Theorem experiments, in which there is a correlation of distant events, have sometimes been cited as evidence of instant communication and hence as supporting the plausibility of mental telepathy. But I have indicated that the experiment does not imply that a signal or other communication can be transmitted instantaneously or faster than the speed of light. In all these cases the lesson to be learned is that phenomena in the world are interdependent and interconnected, not that they are mental in character or intrinsically dependent on the human mind.

2. Life, Freedom, and God

Is there any connection between atomic-level indeterminancy and biological life, human freedom, or God’s action in the world? These questions will all be discussed in later chapters but may be briefly considered here.

1. Biological Life

Quantum theory is the basis of the periodic table and the properties of the chemical elements and molecular bonds, without which there could be no life. But indeterminacy at first appears irrelevant to phenomena at the level of a living cell containing millions of atoms, among which statistical fluctuations will tend to average out. Quantum equations give exact predictions for large ensembles, though not for individual events. Moreover, atoms and molecules have an inherent stability against small perturbations, since at least a quantum of energy is required to change their states. However in many biological systems individual microevents can have macroconsequences. Even in nonequilibrium thermodynamics, small random changes can have large-scale effects. One mutation in a single component of a genetic sequence can change evolutionary history. In the nervous system and the brain, a microevent can trigger the firing of a neuron whose affects are amplified by the neural network.

Holmes Rolston portrays the interaction patterns between cells and atoms: "The macromolecular system of the living cell, like the physicist’s apparatus, is influencing by its interaction patterns the behavior of the atomic systems... There is a kind of downward causation that complements an upward causation, and both feed on the openness, if also the order, in the atomic substructures."36 Rolston says that "biological events are superintending physical ones." Physics leaves out this "upstairs control" but it does allow for a looseness among the lower-level parts. He broadens this analysis to include the action of the mind and human freedom:

If we turn from the random element of indeterminacy to the interaction concept also present, we gain a complementary picture. We are given a nature that is not just indeterminate in random ways, but is plastic enough for an organism to work its program on, for a mind to work its will on. Indeterminacy does not in any straightforward way yield either function, purpose, or freedom, as critics of too swiftly drawn conclusions here are right to observe. Yet physics is, as it were, leaving room in nature for what biology, psychology, social science, and religion may want to insert, those emergent levels of structure and experience that operate despite the quantum indeterminacies and even because of them. We gain space for the higher phenomena that physics has elected to leave out.37

2. Human Freedom

Clearly we cannot identify freedom with randomness. Within physics, the only alternatives are determinate cause and indeterminate chance, and neither can be equated with freedom. But several physicists have asserted that whereas Newtonian determinism excluded human freedom, quantum indeterminacy at least allows for it. They have usually assumed a mind/body dualism; they suggest that a free immaterial mind can determine the behavior of brain atoms which would otherwise be indeterminate.

In place of such a dualism I shall defend the idea of levels of organization and activity. Human experience as an integrated event shows a new type of unpredictability derived not from atomic indeterminacy but from its unitary activity at a higher level. Atomic indeterminacy and human freedom are not, on this view, directly related to each other, and they occur on quite different levels. Coordinated individual events at various levels have multiple potentialities, but only at the level of human selfhood is there freedom in which choices are made in terms of present motives, future goals, and moral ideals. We can talk about freedom only in relation to a model of selfhood that includes past conditioning, continuity of character, personal decision, and individual responsibility.

3. God’s Action in the World

Some authors have suggested that atomic indeterminacies are the domain in which God providentially controls the world. William Pollard, a physicist and priest, has proposed that such divine action would violate no natural laws and would not be scientifically detectable. God, he says, determines which actual value is realized within the range of a probability distribution. The scientist can find no natural cause for the selection among quantum alternatives; chance, after all, is not a cause. The believer may view the selection as God’s doing. God would influence events without acting as a physical force. Since an electron in a superposition of states does not have a definite position, no force is required for God to actualize one among the set of alternative potentialities. By a coordinated guidance of many atoms, God providentially governs all events. God, not the human mind, collapses the wave function to a single value.38

Pollard’s proposal is consistent with current theories in physics. God would be the ultimate nonlocal "hidden variable." But I have three objections to his ideas: (1) Pollard asserts divine sovereignty as total control over all events, and he defends predestination. This seems to me incompatible with human freedom and the reality of evil. It also denies the reality of chance, which becomes only a reflection of human ignorance of the true divine cause. (2) For Pollard, God’s will is achieved through the unlawful rather than the lawful aspects of nature. This may be a needed corrective to deism’s opposite emphasis, but it seems equally one-sided. (3) There is an implicit reductionism in assuming that God acts at the lowest level, that of the atomic components. Do we not want to allow also for God’s influence on higher levels, "from the top down" rather than "from the bottom up"? Isn’t God related to the integrated human self, for example, and not just to the atomic events in the brain?

Arthur Peacocke takes quantum effects to be only one example of chance, which occurs at many points in nature. Moreover, he portrays God as acting through the whole process of chance and law, not primarily through chance events. God does not predetermine and control all events; chance is real for God as it is for us. The creative process is itself God’s action in the world. We will examine this view in detail in chapter 6.

3. Physics and Eastern Mysticism

Several volumes have appeared in the 1970s and 1980s claiming close parallels between contemporary physics and Eastern mysticism.39 The most influential and widely read of these is Eritjof Capra’s The Tao of Physics, which starts by setting forth epistemological parallels. According to Capra, both physics and Asian religions recognize the limitations of human thought and language. Paradoxes in physics, such as the wave/particle duality, are reminiscent of the yin/yang polarity in Chinese Taoism, which portrays the unity of apparent opposites; Bohr himself put the yin/yang symbol at the center of his coat of arms. Zen Buddhism asks us to meditate on koans, the famous paradoxical sayings to which there is no rational solution. Capra also says that mind plays an essential role in the construction of reality: "Ultimately, the structures and phenomena we observe in nature are nothing but the creations of our measuring and categorizing minds."40 He also cites Wigner’s assertion that quantum variables have no definite values until the intervention of human consciousness.

The wholeness of reality is another theme Capra finds in both cases. Quantum physics points to the unity and interconnectedness of all events. Particles are local disturbances in interpenetrating fields. In relativity, space and time form a unified whole, and matter-energy is identified with the curvature of space. Eastern thought likewise presents the unity of all things and speaks of the experience of undifferentiated oneness encountered in the depth of meditation. There is one ultimate reality, referred to as Brahman in India and the Tao in China, with which the individual is merged. The new physics says that the observer and the observed are inseparable, much as the mystic tradition envisages the union of subject and object.

Next, both physics and Eastern thought are said to see the world as dynamic and ever-changing. Particles are patterns of vibration that are continually being created and destroyed. Matter appears as energy and vice versa. Asian religions hold that life is transitory, all existence is impermanent and in ceaseless motion. The dance of Shiva is an image of the cosmic dance of form and energy. But in both fields there is also an underlying timeless realm. Capra maintains that in relativity spacetime is timeless; the eternal now of mystical experience is also timeless.

Capra is particularly enthusiastic about bootstrap theory (or S-matrix theory), which proposes that there are no smallest components of matter but only a network of mutual relations. In this theory, each particle generates other particles, which in turn generate it -- an egalitarian rather than a hierarchical arrangement. Capra compares this to the sense of interdependence in some Asian writings, in which no part is held to be more fundamental than others. He mentions the Hindu image of Indra’s net of jewels, each of which reflects all the other. Unfortunately, bootstrap theory, while promising at the time Capra wrote, has few adherents today since the success of quark theory, which does provide hierarchically ordered constituents (though with the peculiar kind of inseparability mentioned earlier). This section of Capra’s book shows the dangers of tying religious beliefs too closely to particular scientific theories that may turn out to be rather short-lived.

In general, I think Capra has overstressed the similarities and virtually ignored the differences between the two disciplines. Often he finds a parallel by comparing particular terms or concepts, abstracted from the wider contexts that are radically different.41 For example, Asian traditions speak of undifferentiated unity. But the wholeness and unity that physics expresses is highly differentiated and structured, subject to strict constraints, symmetry principles, and conservation laws. Space, time, matter, and energy are all unified in relativity, but there are exact transformation rules. The mystic’s structureless unity, in which all distinctions are obliterated, also seems very different from the organized interaction and cooperative behavior of higher-level wholes, seen already in physics but much more evident in biology. If mechanists see only the parts, Capra gives one-sided attention to wholes. Process thought seems to me to strike a more tenable balance between unity and diversity, with a basic pluralism rather than a monism.

I believe the relation between time and timelessness is also significantly different in physics and in mysticism. Physics deals with the realm of temporal change. I agree with Capra that in the atomic world there is impermanence and an ever-changing flux of events. But I do not agree that spacetime is a static and timeless block. I have argued that relativity points to the temporalization of space rather than the spatialization of time. On the other hand, for much of Eastern mysticism, especially the Advaita tradition in Hinduism, the temporal world is illusory and ultimate reality is timeless. Beneath the surface flux of maya (illusion) is the unchanging center, which alone is truly real, even though the world exhibits regular patterns to which a qualified reality can be ascribed. In Buddhism, timelessness also refers to the realization of our unity with all things, which releases us from bondage to time and the threat of impermanence and suffering. Meditative disciplines do bring the experience of a sense of timelessness (though this may be partly the product of absorptive attention which stops the flow of thought and shifting consciousness).

Capra ignores the diversity among and within Eastern religions and says nothing about Western mysticism. Moreover, he says little about the difference in the goals of physics and mysticism, or the distinctive functions of their languages. The goal of meditation is not primarily a new conceptual system but the transformation of personal existence, a new state of consciousness and being, an experience of enlightenment. We have seen that the mystical strand in both East and West emphasizes experience. There are implicit or explicit beliefs, to be sure, but they must always be considered as components of mysticism as a total way of life.

David Bohm is more cautious in delineating parallels between physics and mysticism. We discussed earlier his idea of instantaneous, nonlocal, noncausal correlations, which would provide an explanation of the Bell’s Theorem experiments. He has extended these ideas as a more general metaphysical system. He proposes that mind and matter are two different projections of the underlying implicate order; they are two related expressions of a single deeper reality. Bohm also finds in Eastern religions a recognition of the basic unity of all things; in meditation there is a direct experience of undivided wholeness. Fragmentation and egocentricity can be overcome in the absorption of the self in the undifferentiated and timeless whole.42 Here is an ultimate monism that contrasts with the greater pluralism of Western religions and of process theology. For Bohm, the answer to the fragmentation of personal life is the dissolution of the separate self, rather than the healing of brokenness by the restoration of relationships to God and the neighbor which Christian thought advocates.

In a recent volume, Science and Mysticism, Richard Jones gives a detailed comparison of themes in the new physics, Advaita Hinduism, and Theravada Buddhism; he emphasizes the differences among them.43 He subscribes basically to what I have called the Independence thesis: science and mysticism are independent and separate, but both have cognitive value. Science has authority concerning objective structures and regularities in the realm of becoming and change, while mysticism is an experience of the unstructured, nonobjectifiable reality beneath the surface multiplicity. For the most part, their claims are incommensurable, and no integration is possible, for they refer to different realms. Science deals objectively with differentiated lawful structures, while the mystic encounters the undifferentiated wholeness of the underlying reality in the experience of meditation. Jones is critical of the vague parallels that Capra draws and his use of phrases abstracted from their contexts.

Jones grants that the classical forms of these Eastern traditions devalued the world of phenomena in a way that offers no encouragement to science. He himself defends the cognitive value of both science and mysticism, each on its own level. He acknowledges that mysticism does not start from uninterpreted experience but inescapably uses theoretical interpretive concepts. Some beliefs might conflict with or be supported by science, and we do not end with total independence. For example, one belief shared by many Eastern traditions is the idea of karma, the infinite cycle of rebirths, which requires an infinite span of time -- and this belief might conflict with some astronomical theories but not others.

Jones accepts the timelessness of ultimate reality in these Eastern traditions. I have greater reservations about this concept. Medieval Christian thought also asserted the timelessness of God, though God was there understood in predominantly personal terms, and the doctrine of creation gave a stronger affirmation of the reality and goodness of the temporal world than is found in most of the East. The God of classical theism was eternal, unchanging, impassible, omniscient, and omnipotent, influencing the world but not influenced by it. But both biblical thought and process theology have had a dynamic understanding of a God who is intimately involved in the temporality of the world. In Hartshorne’s dipolar theism, God is unchanging in purpose but changes in experience of the world.44 We will return in a later chapter to this question of divine temporality and timelessness. At the moment I am suggesting that while timelessness is an important idea in religious thought of both East and West, we can find little support for it in current physics.

4. Conclusions

I have suggested that twentieth-century physics has some important epistemological implications and some modest metaphysical ones. Among the former, the downfall of classical realism has been described. In its place, some interpreters have defended instrumentalism, but I have advocated a critical realism. Theories and models can no longer be taken as literal descriptions of atomic reality, but they can be taken as selective and symbolic attempts to represent the structures of nature that are responsible for particular observable phenomena. The limitations of our theoretical concepts and models are dramatized by the Complementarity Principle, which is a valuable reminder of the partial character of human knowledge. I proposed earlier that there are parallels in the use of complementary models within theology.

Another epistemological lesson can be learned from contemporary physics: the participation of the observer. I have argued that in quantum physics this is required because of the holistic character of wave functions and the interactive character of observation processes. In relativity, it reflects the fact that temporal and spatial properties are now understood to be relationships rather than intrinsic features of separate objects in themselves. In religion, too, knowledge is possible only by participation, though of course the forms of participation differ from those in science. We can ask how God is related to us, but we can say little about the intrinsic nature of God.

Advocates of Independence and Dialogue between science and religion (chap. 1) would want to stop here. They welcome the greater epistemological caution and humility that physics encourages, but they are wary of any metaphysical implications, and also theological ones. The deists were too dependent on the Newtonian world view. They ended with the clockmaker God who designed the world machine. Their error was not just that they used ideas derived from a physics that is now known to be scientifically inadequate. Their mistake, according to these interpreters, was in using any ideas from physics in the formulation of theology. The deists tried to build a metaphysics by an unwarranted extrapolation of the physics of their day. The new epistemology can help liberate theology from bondage to mechanistic physics, but it can equally warn us of the danger of bondage to twentieth-century physics. The chief lesson of the new physics, on this reading, is a negative one -- a warning against repeating the mistakes of the past -- not a positive contribution to the theologian’s task.

Moreover, we have seen that many of the alleged implications of recent physics appear to be questionable. The involvement of the observer in both quantum physics and relativity has often been cited as evidence of the central role of mind. I have argued that it points to the interaction of the observational system with the system observed, not to the presence of mind as such. It is evidence of interconnectedness and holism, not of the pervasiveness of mentality or consciousness. Probability waves may seem less substantial than billiard ball atoms, and matter that converts to radiant energy may appear immaterial. But the new atom is no more spiritual or mental than the old, and it is still detected through physical interactions. If science is indeed selective and its concepts are limited, it would be as questionable to build a metaphysics of idealism on modern physics as it was to build a metaphysics of materialism on classical physics. I have criticized the attempt of Capra and others to portray direct metaphysical parallels between physics and Eastern mysticism, especially with respect to timelessness and holistic unity.

We would also be guilty of a new form of reductionism if we tried to base an inclusive metaphysics on current physics, in which the lowest levels of organization among inanimate structures are studied. But I believe reductionism can be avoided in four ways. (1) We have seen that already within physics we have to look at wholes as well as parts; reductionism is inadequate even within this discipline. (2) We will find that some of the characteristics of nature seen in physics (such as temporality, chance, and wholeness) are also prominent in other sciences. (3) We will go on in subsequent chapters to trace the emergence of higher levels of organization, including life and mind, which cannot be reduced to physics. (4) We will seek metaphysical categories that are adequate for the coherent interpretation, not simply of scientific data, but of all areas of human experience.

This will lead us toward the last of the views in chapter 1, a concern for the Integration of science and religion.

I see three metaphysical implications of current physics, which form a coherent pattern with the implications of other sciences and other areas of human experience.

1. Temporality and Historicity

Time enters into the structure of reality in a more fundamental way in the new physics than in classical physics. The quantum world consists of vibrations which, like musical notes, are nothing at an instant and require time in order to exist. It is a world of dynamic flux in which particles come and go. It is a world of probability states; only the passage of time will disclose which of the alternative potentialities will be actualized. Time is not the unwinding of a predetermined scroll of events but the novel coming-to-be of unpredictable events in history. In relativity, time is inseparable from space. There are no purely spatial relationships, only spatiotemporal ones. All of this is radically different from the Newtonian world of absolute space and time, in which change consisted of the rearrangement of particles that are themselves unchanging. We will find a similar emphasis on change and the emergence of genuine novelty in astronomy and evolutionary biology. The historicity of nature is evident in all the sciences.

2. Chance and Law

There are alternative potentialities for individual events. In accordance with critical realism and the later views of Bohr and Heisenberg, I have interpreted the Uncertainty Principle as an indication of objective indeterminacy in nature rather than the result of subjective uncertainty and human ignorance. The choice between bifurcation paths in nonequilibrium thermodynamics also seems to be a chance phenomenon. We will find the same combination of chance and law in other fields, including quantum effects in the early instants of the cosmos and random mutations in evolutionary history. Human freedom occurs at a totally different level from quantum indeterminacy, but it also exhibits the presence of unpredictable novelty. T. S. Eliot points to the importance of an open future:

Time present and time past

Are both perhaps present in our future

And time future contained in time past.

If all time is eternally present

All time is unredeemable.45

3. Wholeness and Emergence

Against reductionism, which seeks to explain the activity of complex entities in terms of the laws of their components, I have maintained that higher organizational levels involve distinctive patterns of behavior. The Pauli Exclusion Principle, which links physics to chemistry -- but which cannot be derived from the laws governing separate particles -- was offered as one illustration. The inseparability of the observer and the observed was presented as further evidence of interdependence. The correlations between distant events shown in the Bell’s Theorem experiments is a dramatic example of such interconnectedness. In relativity, the unification of space, time, matter, and energy represents wholeness of a fundamental kind. Nonequilibrium thermodynamics describes the emergence of higher levels of systematic order from lower-level disorder.

Later chapters will consider the new wholes that arise with the emergence of life, mind, and society. Looking back, it will not seem unreasonable to claim that even in physics we can see the beginning of a historical, ecological, and many-leveled view of reality. I will suggest that these three characteristics -- temporality and historicity, chance and law, wholeness and emergence -- are prominent in the metaphysics of process philosophy. These reflections will take us far beyond physics, but they will form a pattern coherent with our understanding of the characteristics of physical reality.



1. Readable accounts of quantum theory are given in Heinz Pagels, The Cosmic Code (New York, Bantam Books, 1982), part 1; J. C. Polkinghorne, The Quantum World (London: Penguin Books, 1986).

2. See, for example, James Trefil, The Moment of Creation (New York: Collier Books, 1983), part 2.

3. Niels Bohr, Atomic Theory and the Description of Nature (Cambridge: Cambridge University Press, 1934), pp. 96-101; Atomic Physics and Human Knowledge (New York: John Wiley & Sons, 1958), pp. 39-41, 59-61.

4. Henry Folse, The Philosophy of Niels Bohr: The Framework of Complementarity (New York: North Holland, 1985), p. 237.

5. Ibid., pp. 209 and 255.

6. Ibid., p. 259.

7. C. A. Coulson, Science and Christian Belief (Chapel Hill: University of North Carolina Press, 1955), chap. 3. See also D. M. MacKay, "Complementarity in Scientific and Theological Thinking," Zygon 9 (1974): 225-44.

8. See Barbour, Issues in Science and Religion, pp. 292-94, and Barbour, Myths, Models, and Paradigms, pp. 77-78.

9. Peter Alexander, "Complementary Descriptions," Mind 65 (1956): 145.

10. See Barbour, Issues in Science and Religion, pp. 298-305; also Robert Russell, "Theology and Quantum Theory," in Physics, Philosophy, and Theology. A Common Quest for Understanding, eds. R. J. Russell, W. R. Stoeger, S.J., and G. V. Coyne, S.J. (The Vatican: Vatican Observatory and Notre Dame: University of Notre Dame Press, 1988). A more technical elaboration is M. Jammer, The Philosophy of Quantum Mechanics (New York: John Wiley & Sons, 1974).

11. Albert Einstein letter quoted in M. Born, Natural Philosophy of Cause and Chance (Oxford: Oxford University Press, 1949), p. 122. See also A. Pais, Subtle Is the Lord (Oxford: Oxford University Press, 1982).

12. David Bohm, Causality and Chance in Modern Physics (Princeton: D. Van Nostrand, 1957).

13. Wernel- Heisenberg, Physics and Philosophy (New York: Harper & Row, 1958), and Physics and Beyond (New York: Harper & Row, 1971).

14. See Paul Davies, God and the New Physics (New York: Simon & Schuster, 1983), chaps. 8,12; also Other Worlds (London: Abacus, 1982), chap. 7.

15. See Trefil, Moment of Creation, pp. 111-18.

16. Louis de Broglie, Physics and Microphysics, trans. M. Davidson (New York: Pantheon Books, 1955), pp. 114-15.

17. Jonathan Powers, Philosophy and the New Physics (New York: Methuen, 1982), chap. 4.

18. On the Bell’s Theorem experiments, see Pagels, Cosmic Code, chap. 12; Polkinghorne, Quantum World, chap. 7; Davies, Other Worlds, chap. 6 and God and the New Physics, chap. 8; Fritz Rohrlich, "Facing Quantum Mechanical Reality," Science 221 (1983): 1251-55. Interviews with proponents of differing interpretations are given in P. C. W. Davies and J. R. Brown, eds., The Ghost in the Atom (Cambridge: Cambridge University Press, 1986).

19. Arthur Robinson, "Loophole Closed in Quantum Mechanics Test," Science 219 (1983): 40-41.

20. Davies, Other Worlds, p. 125. See also Henry Folse, "Complementarity, Bell’s Theorem, and the Framework of Process Metaphysics," Process Studies 11 (1981): 259-73.

21. Polkinghorne, The Quantum World, pp. 79, 80.

22. David Bohm, Wholeness and the Implicate Order (Boston: Routledge & Kegan Paul, 1980); David Ray Griffin, ed., Physics and the Ultimate Significance of Time (Albany: State University of New York, 1985); Robert John Russell, "The Physics of David Bohm and Its Relevance to Philosophy and Theology," Zygon 20 (1985): 135-58 (this whole issue is devoted to Bohm).

23. See chapters by John Bell, David Bohm, and Basil Haley in The Ghost in the Atom, eds. Davies and Brown.

24. Among popular accounts of relativity are Lincoln Barnett, The Universe and Dr. Einstein (New York: New American Library, 1952); Davies, Other Worlds, chap. 2; and William Kaufman, Relativity and Cosmology, 2d ed. (New York: Harper & Row, 1977). A more technical exposition is Lawrence Sklar, Space, Time, and Spacetime (Berkeley and Los Angeles: University of California Press, 1974).

25. Quoted in Davies, Other Worlds, p. 50.

26. Milic Capek, "Relativity and the Status of Becoming," Foundations of Physics 5 (1975): 607-17.

27. Andrew Dufner and Robert John Russell, "Foundations in Physics for Revising the Creation Tradition," in Cry of the Environment, eds. Philip Joranson and Ken Butigan (Santa Fe: Bear & Co., 1984).

28. Karl Heim, Christian Faith and Natural Science (New York: Harper and Brothers, 1953), pp. 133-34.

29. John Wilcox, "A Question from Physics for Certain Theists," Journal of Religion 41 (1961): 293-300; Lewis Ford, "Is Process Theism Compatible with Relativity Theory?" Journal of Religion 48 (1968): 124-35; Paul Fitzgerald, "Relativity Physics and the God of Process Philosophy," Process Studies 2 (1972): 251-76.

30. Davies, God and the New Physics, chap. 5.

31. Ilya Prigogine and Isabelle Stengers, Order out of Chaos (New York: Bantam Books, 1984).

32. James Jeans, The Mysterious Universe (Cambridge: Cambridge University Press, 1930), p. 186.

33. Arthur Eddington, The Nature of the Physical World, (Cambridge: Cambridge University Press, 1928), p. 244.

34. Eugene Wigner, Symmetries and Reflections (Bloomington: Indiana University Press, 1967), p. 172.

35. John A. Wheeler, "Bohr, Einstein, and the Strange Lesson of the Quantum," in Mind and Nature, ed. Richard Elvee (San Francisco: Harper & Row, 1982); "The Universe as Home for Man," American Scientist 62 (1974): 683-91; "Beyond the Black Hole," in Some Strangeness in the Proportion, ed. Harry Woolf (Reading, MA: Addison-Wesley, 1980).

36. Holmes Rolston, Science and Religion: A Critical Survey (New York: Random House, 1987), p. 53.

37. Ibid., p. 52.

38. William Pollard, Chance and Providence (New York: Charles Scribner’s Sons, 1958).

39. Gary Zukav, The Dancing Wu Li Masters (New York: William Morrow, 1979); William Talbot, Mysticism and the New Physics (New York: Bantam Books, 1981); Amaury de Riencourt, The Eye of Shiva (New York: William Morrow, 1981); Ken Wilber, ed., Quantum Questions: Mystical Writings of the World’s Greatest Physicists (Boulder, CO: Shambhala, 1984).

40. Fritjof Capra, The Tao of Physics (New York: Bantam Books, 1977), p. 266.

41. Sal Restivo, "Parallels and Paradoxes in Modern Physics and Eastern Mysticism," Social Studies of Science 8 (1978): 143-81 and 12 (1982): 37-71.

42. David Bohm, Wholeness and the Implicate Order, chap. 7; "Religion as Wholeness and the Problem of Fragmentation," Zygon 20 (1985): 124-33.

43. Richard Jones, Science and Mysticism (Lewisburg, PA: Bucknell University Press, 1986).

44. Charles Hartshorne, The Divine Relativity (New Haven: Yale University Press, 1948).

45. T. S. Eliot, Burnt Norton (London: Faber & Faber, 1941), p. 9. Used by permission of Faber & Faber.