Cosmology, Physical Aspects

The scientific understanding of the origin, nature, and possible future of the universe dramatically changed during the twentieth century. This burst of scientific discovery triggered a complex series of responses among religious thinkers, particularly after about 1960, which marks the beginning of the contemporary resurgence of dialogue between science and religion. The recent interaction between scientific cosmology and religious thought is one of the richest and most instructive examples of contemporary science-religion dialogue.

Theologians have related physical cosmology most often to the doctrine of creation. In its Christian form, creation theology typically includes two components: creatio ex nihilo (creation out of nothing) and creatio continua (continuous creation). Judaism and Islam explicate similar ideas, but the formal distinction is an invention of Christian theology to express different features of the God-world relation. Creatio ex nihilo stresses the dependence or contingency of all that exists on God as its transcendent source while creatio continua stresses God's continuing and immanent action in the universe. Together, these ideas portray God both as the ultimate source of nature's causal efficacy, faithfully maintaining its regularities, which we describe in terms of the laws of nature, and as creating in time by acting in, with, under, and through the laws of nature, bringing forth the order, beauty, and complexity of the physical world and the rich diversity found in the biological evolution of life.

Creation ex nihilo has been explored extensively in relation to two particular features of Big Bang cosmology: t = 0, which represents the beginning of time and thus the age of the universe, and the Anthropic Principle, which points to the remarkable conditions that the fundamental constants and the laws of nature must meet if the evolution of life in the universe is to be possible. These will be discussed in turn, each followed by theological discussions of its significance for creatio ex nihilo. The creatio continua form has been discussed in terms of the temporal, developmental, and historical character of the universe; it will not be treated here. Finally, inflationary and quantum cosmologies will be discussed in advance of a survey of theological responses.

Big Bang cosmology

During the decade following the 1905 publication of his Special Theory of Relativity, Albert Einstein worked on a relativistic theory of gravity. His basic insight was to reconceptualize gravity as the curvature of space-time instead of as a (Newtonian) force in Euclidean space. According to Einstein, masses move along geodesics, curves describing the shortest possible path in space-time. Their motion, in turn, alters the curvature of space-time, thus giving the field equations of the General Theory of Relativity their complicated nonlinear form.

Shortly after the discovery of the General Theory of Relativity, solutions to Einstein's equations were developed for two distinct classes of problems: (1) point masses, which when applied to the solar system led to several key tests of the theory and their eventual confirmation (including the deflection of starlight by the sun and the precession in the perihelion of the orbit of Mercury); and (2) dust, which when eventually applied to the distribution of galaxies and galactic clusters described the universe as expanding in time. Beginning in the 1920s, telescopic observations by Edwin Hubble showed that galaxies were indeed receding from us and at a velocity proportional to their distance. In essence, the expansion of the universe had been discovered.

There are in fact three standard types of expansion possible. In the so-called closed model, the universe has the shape of a three-dimensional sphere of finite size. It expands up to a maximum size, approximately one hundred to five hundred billion years from now, then contracts, eventually collapsing to vanishing size with infinite temperatures and densities. The so-called open model has two variations, one in which the universe is flat, and one in which it is saddle-shaped. In both versions of the open model, the universe is infinite in size. In both cases the universe will expand forever and cool towards absolute zero. The future of these three models is often used to characterize them as "freeze" (open) or "fry" (closed).

All three models came to be called Big Bang models because they describe the universe as having a finite past life of twelve to fifteen billion years and as beginning in a singularity, an event of infinite temperature, infinite density, and zero volume in which the laws of physics as we know them break down. Since the age of the universe t is calculated as starting here, it is convenient to label the singularity "t = 0"; technically this event is referred to as an essential singularity. In the 1960s, Stephen Hawking, Roger Penrose, and Robert Geroch proved key theorems demonstrating that the existence of an essential singularity such as t = 0, given Einstein's General Theory of Relativity, was unavoidable.

The relevance of t = 0 to creation ex nihilo

To what extent is t = 0 relevant to the doctrine of creation ex nihilo ? Responses have ranged widely from direct relevance to complete irrelevance.

Direct relevance. For some scholars, the scientific discovery of an absolute beginning of all things (including time) provides empirical confirmation, perhaps even proof, of divine creation. This was the position taken by Pope Pius XII in 1951 in an address to the Pontifical Academy of Sciences. In 1978 Robert Jastrow, then head of NASA's Goddard Institute for Space Studies, spoke metaphorically about scientists who, after climbing the arduous mountain of cosmology, came to the summit only to find theologians there already. The idea that t = 0 provides strong, even convincing, support for belief in God is frequently advanced by conservative and evangelical Christians such as Hugh Ross. Early in the debate, Lutheran theologian Ted Peters advanced a more nuanced argument elucidating the theological importance of a beginning to the universe in terms of "consonance" between theology and Big Bang cosmology. A sophisticated argument for the temporal finitude of the universe based on t = 0, as well as on an argument that rejects the possibility that the universe is also actually infinite in size, has been developed by philosopher William Craig, partially through an explicit debate with atheist Quentin Smith. More recently, philosopher Phil Clayton has suggested that contemporary cosmology affords a clear case of divine activity.

t = 0 also has served indirectly to inspire the construction of an alternative, and quite successful, cosmology. In the 1940s, Fred Hoyle, an outspoken atheist, together with colleagues Hermann Bondi and Thomas Gold, constructed a cosmology that would have no temporal beginning or end. Their "steady state cosmology" depicted the universe as eternally old and expanding exponentially forever. For two decades, the Big Bang and the steady state models seemed equally viable given the empirical evidence then available. By the mid-1960s, however, the Big Bang model was vindicated, at least in most scientists' minds, by the discovery of the microwave background radiation, the successful prediction of the cosmological abundances of hydrogen and helium, and other effects. What is important here, however, is Hoyle's motivation in developing the steady state cosmology. One reason, although probably only secondary, was his concern that Big Bang cosmology seemed, at least in the public mind, to support Christianity. Of course, the scientific community must test strictly any cosmological proposal—steady state or Big Bang—regardless of its possible ideological origins. As philosophers put it, the "context of discovery" should not influence the "context of justification." Nevertheless, the story of Hoyle demonstrates that very fruitful ideas can come from "extra scientific" disciplines, such as philosophy and theology, and lead even if indirectly to scientific theories with testable consequences.

Complete irrelevance. Several of the most important scholars in the theology and science interaction see creatio ex nihilo as an entirely philosophical argument regarding contingency for which specific empirical evidence is irrelevant. This includes scientists such as Arthur Peacocke, John Polkinghorne, Bill Stoeger, and Ian Barbour (in his early writings) as well as Thomistic scholars such as Steven Baldner and William Carroll.

Indirect relevance. There are a variety of positions that one can take between the two extremes of direct relevancy and complete irrelevancy. Those who find various forms of indirect relevance include scientists such as Ian Barbour (in later work), George Ellis, Walter Hearne, and Howard Van Till; and philosophers and religious scholars such as Ernan McMullin, Nancey Murphy, Ted Peters (in later work), Mark Worthing, and Robert John Russell. Russell's way of articulating indirect relevance is to point out that t = 0 is relevant to the aspect of contingency within the idea of creation to various degrees depending on the sort of contingency considered. For example, three basic types of contingency can be distinguished: global contingency, local contingency, and nomological contingency. The first of these, global contingency, includes both the existence of the universe as such (global ontological contingency) and contingent theoretical or empirical aspects of the universe as a whole (global existential contingency). The particular sort of contingency associated with t = 0 would come under the latter—it is a form of past temporal finitude, which is a form of finitude and thus a species of global existential contingency—but not the former. Thus, the universe's existence and its beginning relate to different strands of global contingency. It is important to note, however, that the infinite size and infinite future of the two open models of the universe argue against contingency in the very same respect. In other words, if t = 0 is "consonant" with creation theology in respect of "global existential contingency" then these infinities are "dissonant" with creation and other theological doctrines, such as the eschatological views of Western religions, in exactly the same respect.

The Anthropic Principle

The term Anthropic Principle was coined by physicist Brandon Carter in 1974 to bring together various apparent coincidences about the universe that had received scattered attention throughout the twentieth century. Although formulated in a variety of ways, in its strongest form the Anthropic Principle poses the following question: How are we to explain the fact that the values of the fundamental constants of nature (e.g., the speed of light, Planck's constant, etc.) and the form of the fundamental physical laws are "fine-tuned" to precisely what is needed if the evolution of life is to be possible? Estimates have been made suggesting that if the values of the natural constants differed from their actual values by one part in a million, it would have been impossible for life to have evolved in the universe.

To some, then, the universe seems "fine-tuned" for life, suggesting a cosmological version of the traditional design argument for God. Opponents have deployed a variety of "many-worlds" arguments to suggest that there are many universes besides our own, each with different values of the natural constants, perhaps even different physical laws. In that scenario, by definition, life would evolve in the particular universe that satisfies the conditions for life but not in others, which explains cosmic fine-tuning without having to invoke a designer to explain the anthropic coincidences. What are the relative scientific, philosophical, and theological merits of these opposing positions?

As early as 1979, Peacocke gave the Anthropic Principle an indirect but important role within his discussion of the doctrine of creation, using metaphors of God as elaborating a fugue and as a bell-ringer sounding the changes. George Ellis has explored what he calls the "Christian Anthropic Principle," combining design perspectives with a theology of divine omnipotence and transcendence, drawing from William Temple. Nancey Murphy, however, treats Ellis's thesis as an argument for God. She reconstructs Ellis's paper to show that theology can be seen as a science and that cosmological fine-tuning can serve as an "auxiliary hypothesis" in such a theological program. Richard Swinburne and John Polkinghorne have also drawn on the Anthropic Principle in constructive ways.

The endorsements are not universal, however. Theologian Mark Worthing cautions that the "designer" of the universe need not be the creator God of theism: both a divine demiurge, including the universe itself, as Richard Dawkins suggests, or an emerging divinity, as John Barrow and Frank Tipler propose, take into account the empirical evidence of fine-tuning. According to Barbour, the theological virtues of construing the Anthropic Principle as a modern design argument are minimal.

Philosopher John Leslie's overall evaluation is that the two opposed sides are equally strong as arguments but also equally incorrect because a fully adequate conception of God is neutral to cosmological details—Leslie articulates God in terms of a neo-Platonic aesthetic/ethical principle. Most variations on the Platonic idea of God as the form of the Good and the neo-Platonic idea of God as Ground of Being are neutral to cosmological details, and their defenders are inclined to regard design arguments based on the Anthropic Principle and the many-worlds opponents as premature. Historian of science Ernan McMullin points out that the Anthropic Principle is highly vulnerable to theory-change in science. A quantum cosmology needs to gain widespread acceptance before the force of the Anthropic Principle can be assessed properly.

The Anthropic Principle can, however, play a fruitful role if incorporated within ongoing constructive theology, illuminating its inner meaning and suggesting connections between theological topics we might not otherwise have recognized. For example, the Anthropic Principle underscores the key role that Planck's constant plays in the particular overall structure of the universe, a role that a theology of creation ex nihilo would need to take seriously. The same constant may be a critical factor in compatibilist discussions of free will and thus for theological anthropology: For us to act freely, nature at the physical level must, arguably, be indeterministic. It also functions pivotally in some approaches to noninterventionist divine action, particularly in the context of theistic evolution.

Inflationary and quantum cosmologies

Since the 1970s, scientists have pursued "inflationary Big Bang" and beyond that "quantum cosmologies." The motivation for this has been both to solve a variety of technical problems in the standard Big Bang model and to blend cosmology with quantum physics, which studies atomic and subatomic physical systems. The term quantum cosmology sounds oxymoronic, but the Big Bang entails that the very early universe was extremely small and thus subject as a whole to quantum physics. Physicists were also seeking to produce a theoretical unification of gravity and the other physical forces (the electroweak and strong nuclear forces), a unity that is thought to be physically evident only at extraordinarily high energies such as those present in the early stages of the Big Bang.

With the introduction of the "inflationary Big Bang" scenario by Alan Guth and colleagues in the 1970s and further developments in this direction in the 1980s, the technical problems were basically solved. According to inflation, the extremely early universe (roughly from t = 0 until the Planck time, which is 10-43 seconds) expands extremely rapidly, then quickly settles down to the expansion rates of the standard Big Bang model. During inflation, countless cosmic domains may arise, separating the overall universe into huge portions of spacetime in which the natural constants and even the specific laws of physics might vary. The effect of inflation on the problem of t = 0 is fascinating, however, because the Hawking-Penrose theorems mentioned above do not apply during the inflationary epoch. In these cosmologies we may never know whether or not an essential singularity was part of the universe's history.

Many physicists have proposed methods to unify quantum physics and gravity, subsequently applying the results to create quantum cosmologies: Hawking and Jim Hartle, Andrei Linde, Chris Isham, Guth, Hawking and Alan Turek, and others. All of these proposals are still highly speculative, but there are some indications of what different quantum cosmologies might look like, including models with or without an initial singularity (eternal inflation), with open or closed domains embedded in an open or a closed megauniverse, and so on. In most quantum cosmologies, our universe is just one part of an eternally expanding, infinitely complex megauniverse. Quantum cosmology is a highly speculative field chiefly because the underlying theories of quantum gravity are notoriously hard to test empirically, and they lift the philosophical issues already associated with quantum mechanics to a much more complex level since the domain of application is now the entire universe.

t = 0 revisited in inflationary and quantum cosmologies. Given the speculative status of quantum cosmology, some scholars have kept the theological conversation focused on the standard Big Bang model. Others, though, have asked what effects quantum cosmology might have on their theology of creation.

One argument is to invoke, once again, the argument for God from the sheer existence of the universe. Thus, even without an initial singularity, even the endless number of universes suggested by inflation and most quantum cosmologies is contingent in some sense and so invites a creator God as their necessary complement and creative source. A related point is that the prior universe or ensemble of universes out of which our universe arose includes quantum fields governed by the laws of physics (both of which are needed to give what passes in quantum cosmologies for a scientific account of the quantum creation of the universe). But the Christian view of creatio ex nihilo relies on the meaning of "nothingness" out of which God created all that is as the absolute lack of anything. Hawking, for example, seems to argue in part in this way in A Brief History of Time (1988). At times in the book Hawking seems to agree that without a t = 0 there is nothing left for God to do, but not at the end, for he also writes: "even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe? The usual approach of science … cannot answer the question of why there should be a universe for the model to describe" (p. 190).

It is also possible to see, in the debates over approaches to quantum cosmology, the striking presence of extrascientific factors. A fascinating example occurs in comparing proposals by Penrose and Hawking and Hartle. In Penrose's view, our universe arises as an arbitrary quantum fluctuation in a homogeneous background superspace filled with quantum fields. But why should any point in superspace be singled out as creating a universe like ours? As Isham puts it, the problem was preempted by the response of Augustine of Hippo (354–430) to the question of what God was doing before God made the universe. Augustine's answer was that God did not create the universe in time, since the decision as to which point in time to create it would be arbitrary and would imply that God's will is mutable. Instead Augustine claimed that God created time along with the creation of the universe. But as Isham points out, the same reasoning leads us to reject Penrose's approach: It is thoroughly arbitrary to pick a creation point in superspace. The Hawking-Hartle model, on the other hand, circumvents the need for such a point, making it more attractive to many scientists. This is a striking example of the potentially positive role philosophy and theology can play in stimulating new insights and directions of inquiry within the natural sciences.

In short, then, inflation and quantum cosmologies can point to the grandeur and mystery of God's creativity and undercut our anthropocentrism by stressing a creation far beyond anything we could ever observe, one in which God relishes and delights in its sheer diversity. Moreover, none of the scientific cosmologies explains why the "universe" exists as such, leading us once again to the possibility of recognizing God as the creative ground of being.

Anthropic principle revisited in inflationary and quantum cosmologies. In the inflationary Big Bang scenario, the "universe" (or megauniverse) includes an infinity of domains, each a "universe" unto itself, with its own values of the fundamental constants, perhaps even differing laws of nature. In Linde's quantum cosmology, the universe eternally inflates into an infinity of bubble universes, themselves inflating into others endlessly. These scenarios suggest a far more ontologically stark "many-worlds" character than those of standard Big Bang cosmology, though they are far less defensible empirically. At least in theory they seem to explain fine-tuning by means of a kind of "cosmic Darwinism," rendering the design argument irrelevant.

Those defending an application of the Anthropic Principle to a design argument tend to stress the technical and philosophical problems with inflation and quantum cosmologies. They also tend to appeal to Ockham's Razor against many-worlds or multiverse theories and in support of the Big Bang, and they invoke God as the simplest explanation of fine-tuning. Critics of an application of the Anthropic Principle to a design argument tend to view standard Big Bang cosmology as outdated while appealing to philosophical criticisms to the effect that judgments of design are unreliable because they are necessarily limited by human imaginations.

Conclusion

Perhaps the most important result to emerge from the shifts in cosmology over the late twentieth century is the emergence of the hot Big Bang as a "permanent" description of our universe from the Planck time some twelve to fifteen billion years ago until the present. Gone is the time when the Big Bang theory enjoyed a serious challenger in the form of Hoyle's steady state model, with its picture of a single, ever-expanding universe whose fundamental features were time-independent. Instead the domain of debate has shifted to the pre-Planck era and what might lie endlessly "before" the Big Bang in quantum superspace. We have witnessed what Joel Primack and Nancy Abrams call an "encompassing" revolution as distinguished from the kind of Kuhnian "replacing revolution" one usually thinks of when scientific paradigms change. In such an encompassing revolution, the new paradigm contains the old one as a limit case; that is, quantum cosmology encompasses Big Bang cosmology as a special case when quantum effects can be ignored. To paraphrase a point made by Charles Misner, we can have confidence in relying on the Big Bang scenario because we know just where it fails: prior to the Planck time. In this sense the Big Bang is here to stay.

See also Anthropic Principle; Big Bang Theory; Cosmology; Cosmology, Religious and Philosophical Aspects; Creatio Continua; Creatio Ex Nihilo; Inflationary Universe Theory; Many-worlds Hypothesis; Quantum Cosmologies; Steady State Theory; T = 0

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cosmology and creation—books

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robert john russell