Religion in an Age of Science by Ian Barbour
Ian G. Barbour is Professor of Science, Technology, and Society at Carleton College, Northefiled, Minnesota. He is the author of Myths, Models and Paradigms (a National Book Award), Issues in Science and Religion, and Science and Secularity, all published by HarperSanFrancisco. Published by Harper San Francisco, 1990. This material was prepared for Religion Online by Ted and Winnie Brock.
Chapter 6: Evolution and Continuing Creation
The publication of Charles Darwinís On the Origin of Species in 1859 was the most important event in an intellectual revolution that continues to affect many areas of thought. The concept of evolution has changed our understanding of nature and thereby challenged our views of humanity and our view of Godís relation to nature.
There were evolutionary ideas before Darwin, but his writings presented the first systematic theory along with extensive supporting evidence. Serving as naturalist on the HMS Beagle during a five-year voyage around the world, Darwin had observed many small variations between similar species. Six years later, reading Malthusís essay on human populations competing for limited resources, he found the clue for a theory by which to interpret the data collected on the voyage. Two ideas were central in his theory of evolution. First, in every population there are small random variations, which can be inherited. Second, in the struggle for survival some of these variations confer a slight competitive advantage, leading over a period of many generations to the natural selection of the characteristics that contributed to survival. Darwin argued that through such natural selection new species have come into existence. In The Descent of Man (1871) he extended his theory to include human origins.
Previously it had usually been assumed that the forms of all living things were fixed when they were created. The order of nature was thought to be essentially static and unchanging. In the evolutionary view, all nature is dynamic, changing, and historical in character. Previously, humanity was sharply distinguished from the rest of nature. Since Darwin, humanity has been understood to be part of nature, the product of a common evolutionary heritage. Darwin looked on nature as a network of interacting, interdependent beings, and in this respect he can be considered a forerunner of ecology.
Darwinís theory also represented a threefold challenge to traditional Christianity.
1. A Challenge to Biblical Literalism. A slow process of evolution cannot be reconciled with the seven-day creation in Genesis. This was not a new challenge. Earlier in the century, uniformitarian geology and the fossil evidence of extinct species had pointed to a long history of life on earth. On the other hand, symbolic rather than literal interpretations of Genesis had been defended earlier by many Christian writers, including Augustine, Luther, and Galileo. In response to Darwin, some theologians defended biblical inerrancy and rejected all forms of evolution, but they were in the minority. Most conservatives reluctantly accepted evolution (though sometimes insisting on the special creation of the human soul). The liberals, on the other hand, welcomed the growth of science and said that evolution was consistent with their optimistic view of historical progress. They were soon speaking of evolution as Godís way of creating. Most Christians were able to accommodate this challenge, though for the "scientific creationists" it is still an issue, as we have seen.
2. A Challenge to Human Dignity. Previously, human beings had been set apart from all other creatures, their unique status guaranteed by the immortality of the human soul and the distinctiveness of human rationality. But now humanity was treated as part of nature. No sharp line separated human and animal life, either in historical development or in present characteristics. Darwin and many of his successors stressed the similarities of human and animal behavior, minimizing any distinctive features of human language and culture. The "social Darwinists," such as Herbert Spencer, used "the survival of the fittest" to justify a competitive economic and social order. Darwinism seemed to pose a major threat to human self-understanding. We will consider human nature in the light of evolution in the next chapter.
3. A Challenge to Design. In 1802, William Paley had given the classic rendition of the argument from design. If you find a watch on the ground, with intricately coordinated parts, you infer that there must have been a watchmaker. The human eye is an even more wonderful structure, integrated around the one purpose of vision. Within a static universe, the complex functioning of the various parts of organisms and their harmonious adaptation to their surroundings seemed to be strong evidence of an intelligent designer. But Darwin showed that adaptation could be accounted for by an impersonal process of variation and natural selection. The year after his first book was published, he wrote to the Harvard biologist Asa Gray: "I am inclined to look at everything as resulting from designed laws, with the details, whether good or bad, left to the working Out of what we may call chance. . . . I cannot think that the world as we see it is the result of chance; yet I cannot look at each separate thing as the result of Design."1
Asa Gray himself said that evolution was Godís way of creating; design is evident in the whole process of chance and law by which diverse forms came into being. But some of Darwinís successors, such as T. H. Huxley, attacked even this wider design argument, asserting that humanity is the product of impersonal and purposeless forces. The question of design was the most influential and enduring of these three challenges, and we will give particular attention to it in this chapter.
I. Evolutionary Theory
Since Darwinís day, scientists have accumulated an immense amount of evidence supporting both the historical occurrence of evolution and the hypothesis that variations and natural selection are the main causes of evolutionary change. But vigorous debates continue concerning some of the details of their operation and the role of other factors. We must look at the role of DNA and current theories about the origin of life. Information theory and systems theory also throw light on the historical evolution of organisms and their present functioning.
1. The Modern Synthesis
In the twentieth century, work in population genetics has greatly advanced our understanding of the inheritance of variations, about which Darwin could only speculate. Mendelís laws of heredity were studied in plant, insect, and animal populations, both in the field and in the laboratory. It was also found that an occasional individual had a characteristic, such as eye color, which differed markedly from the rest of the population. The frequency of such mutations could be increased by exposure to Xrays and certain chemicals. Mutations and the recombination of units of heredity (genes) from two parents were seen to be the main sources of variation, and both were evidently random processes unrelated to the needs of the organism. Genetics and evolutionary theory were brought together in a systematic neo-Darwinian framework, to which Julian Huxley in 1942 gave the name "the Modern Synthesis." Among its exponents have been Ernst Mayr, Theodosius Dobzhansky, and Gaylord Simpson.2
Population studies also greatly extended our understanding of natural selection. A "species" was identified with a reproductive population rather than a characteristic type. There is usually considerable diversity within a population, and evolution occurs when a shift takes place in the relative frequency of genes. In the Modern Synthesis, evolution was thought to occur slowly and gradually by the accumulation of small changes. Often these changes are induced by a changing environment. Mutants not useful in one environment may turn out to be highly adaptive in other surroundings. Among a species of light-colored moths there occurs a rare dark mutation, which is conspicuous against light-colored tree trunks and is picked off more rapidly by birds. But on the soot-darkened trees of industrial areas, the dark moth is less conspicuous; in the past century it has completely supplanted the light-colored form in parts of England.
In Darwinís day, natural selection was understood primarily as the survival of the fittest under conditions of competitive struggle. In this century, selection was equated with differential reproduction and survival, and the importance of cooperation as well as competition was recognized. Sometimes symbiotic cooperation between two species enables both to survive. At other times a division of labor among diverse members of a social group, such as a termite colony, may be the key to its success. The study of ecosystems has traced complex patterns of interdependence in biotic communities.
Recent techniques for comparing the molecular structure of similar proteins in various living species allow us to estimate the time since their lineages diverged. For example, the enzyme cytochrome-C in human beings consists of a sequence of 104 amino acids. In the comparable sequence in rhesus monkeys, only one of these amino acids is different; horses have 12 that differ, and in fish there are 22, indicating increasingly distant kinship. The evolutionary history established by this biochemical method agrees well with evidence derived from two completely different disciplines: the study of fossil records by paleontologists, and the comparison of the anatomy of living species by taxonomists.3
Before Darwin, Lamarck had claimed that evolution occurred because an animalís behavior produced physiological modifications that were inherited by its offspring. The giraffeís neck is long, he said, because it has been stretched by generations of reaching for leaves on trees. Such a direct inheritance of acquired characteristics was subsequently discredited. In reaction to Lamarckianism, Darwinians tended to minimize the role of the organismís own behavior in its evolution. Change was viewed as the product of the external forces of natural selection acting on an essentially passive population.
But early in this century, Baldwin and Lloyd Morgan defended "organic selection"; they granted that the environment selects organisms, but they pointed out that organisms also select their own environments. More recently, C. H. Waddingtonís idea of genetic assimilation underscores the importance that behavior can have, without violating Darwinís basic postulates. He assigns great significance to an indirect effect whose long-term results are similar to Lamarckianism. Suppose that during a time of food scarcity a species of birds adopts a new habit of probing for insects under the bark of trees. Thereafter, those mutations or variations associated with longer beaks will tend to survive more efficiently and will be selected. Novel activities can thus bring about novel forms. Functional changes may precede structural ones. A new behavior pattern can thus produce an evolutionary change, though not in the simple way Lamarck assumed.4
Alister Hardy contends that modern biologists have emphasized the mechanical role of external forces acting on random mutations and have neglected the fact that internal drives can decisively modify evolution. He discusses the curiosity and initiative of animals, their self-adaptation, instinct and learning, and other findings of ethnology. He concludes, "I think we can say, from the many different lines of argument, that internal behavioral selection due to the Ďpsychic lifeí of the animal, whatever we think about its nature, is now seen to be a most powerful creative element in evolution."5 We do not have to imagine that random mutations at the molecular level are the chief agent in the initiation of change; they may serve rather to perpetuate changes first introduced by the initiative of the organism itself. Of course, this does not imply that organisms were trying to evolve, but only that purposive behavior as well as chance mutation was important in setting the direction of evolutionary change.
2. Current Debates
Several features of the Modern Synthesis have been challenged in recent years. In some cases the critics call for an extension of the synthesis; in others they modify some of its assumptions.
1. Punctuated Equilibrium
Starting in the 1930s, Goldschmidt and others challenged the assumption that evolution occurs through the gradual accumulation of small changes. They said that laboratory studies had documented only changes within species, not the formation of new species. Few fossils had been found representing transitions between species, much less between major types (classes or phyla). They proposed that new species and phyla arise suddenly from very rare cases in which a viable creature is produced by "systemic" mutations, such as those that modify an early stage of the embryoís development.6
More recently, Stephen Jay Gould and Niles Eldredge have defended "punctuated equilibrium." The fossil record shows long periods of stasis -- millions of years with very little change -- interspersed with bursts of rapid speciation in relatively short periods. They postulate that whole developmental sequences changed at once, leading to major structural changes. Speciation could occur rapidly if a small population was geographically isolated. They claim that previous evolutionary theory was not false but incomplete, especially in accounting for speciation.7
Proponents of the Modern Synthesis reply that their theory is more varied and flexible than these critics acknowledge. The absence of transitional forms is a result of the incompleteness of the fossil record. Changes that appear rapid on the scale of geologic time (over a period of fifty thousand years, let us say) can encompass many generations. Thus Stebbins and Ayala think that many of Gouldís ideas can be included in an enlarged version of the neo-Darwinian synthesis.5 The remaining debate seems to be mainly over the relative importance of small and large variations in evolutionary change.
2. Nonadaptive Changes
The Modern Synthesis held that natural selection is the primary directive force in evolution and that every new trait is an adaptation contributing to survival. Some critics suggest that this is an unfalsifiable claim, since one can always think up a possible selective advantage or introduce ad hoc auxiliary hypotheses for which there is no independent evidence. Gould and Lewontin attack such "panselectionism" and suggest that selection is an important but not exclusive factor. "Selection may be the ultimate source of evolutionary change, but most actual events owe more of their shape to its nonadaptive sequelae."9
It has been known for some time that detrimental changes do occur. For example, the antlers of the Irish elk evolved to such enormous size that they became very unwieldy. Many such changes can be explained as byproducts of other changes, since a constellation of genes controls a whole package of developmental processes. (In this case, larger antlers may have accompanied larger and stronger bone structures, which would have conferred a selective advantage.) Organisms are integrated wholes, and a particular gene may hitchhike with other genes that are selected. Structures originally arising for one function can later be coopted for other purposes that contribute to survival.
Genetic drift from neutral mutations is another form of nonadaptive change. Many variations neither foster nor hinder survival, and their perpetuation seems to have been a matter of chance. If a large population is broken up into small groups, statistical or sampling variations will be present among the groups. In changing environments, a small isolated population might have been a bottleneck of evolutionary history, and the particular genes that it perpetuated may have been a matter of chance rather than selective advantage.10
3. Multilevel Selection
In the Modern Synthesis, individual organisms are selected and their genes are passed on. But Wyne-Edwards, Hamilton, and others focused attention on groups of related organisms. A birdís warning cry endangers individual survival, but it helps the survival of a kinship group with shared genes. Such "altruistic" behavior would contribute to inclusive fitness and kin selection. These phenomena are prominent in the writings of Wilson, Dawkins, and other sociobiologists; in the next chapter we will examine their claims concerning altruism and genetic determinism. Here we note that they see selection as operating on kinship groups to maximize the transmission of their genes. Critics have seen these views as reductionistic, and they propose a hierarchical model in which selection occurs at a variety of levels.
Hull and others have argued that a species is an important unit of selection. The history of a species is similar to that of an organism, but on a much longer time scale. An organism produces other organisms by reproduction; a species produces other species by speciation. An organism perishes in death; a species perishes in extinction. As we ask about high reproductive rates in organisms, so we might ask what characteristics of a species produce high speciation rates. There can thus be branching, persistence, and selection of inheritable variations on several levels at once. Changes at one level will constrain those at another level. 11
4. The Active Role of Genes
In neo-Darwinism, random mutations and the recombination of genes provide the raw material of change, but the directionality of evolution is entirely the result of natural selection. The genes are completely passive before the selective forces of the environment. But some biologists suggest that genes play a more active role in their own evolution. For one thing, the mutational repertory of a gene is a function of its structure, which limits the operation of chance. Some changes are the result of the transposition of genes, and transposability is a function of gene structure. Some enzymes also promote mutation. The ability to evolve faster depends on internal as well as external factors. A species can in effect learn to evolve, using strategies successful in the past.12
Most molecular biologists have accepted the assumption (often called the Central Dogma) that information in organisms passes in only one direction, from genes to proteins. But Stuart Kaufman and others have shown that there are ways in which proteins affect genes.13 Some enzymes manipulate the genetic message in response to signals from the environment. Immune systems act as sensors for environmental and bodily changes, and there are codes for gene repair in response to damage. Moreover, embryonic development takes place according to basic forms, structures, and rules that limit the options. The developmental pathways channel change and constrain the morphological possibilities. Some of this developmental information resides in the cellís cytoplasm.14 These claims suggest the need for a considerable enlargement of the Modern Synthesis, though not its total rejection.
3. DNA and the Origin of Life
The discovery of the structure of DNA by Watson and Crick in 1953 opened the door to the analysis of genes at the molecular level. The DNA molecule was shown to be a double strand. At regular intervals along each strand is a projecting nucleotide base (one of four bases, abbreviated A, C, G, and T), which is linked to a base in the opposite strand. The base pairs form cross-links like the rungs of a ladder. An A base will link only with a T base, and C only with G. Here was a mechanism for one of the crucial properties of genes: replication. If the two strands separate, every base in each strand will attract a new partner base (from the surrounding fluid) and build up a new partner-strand identical to the old one, with A, C, G, and T units in exactly the same order. Mutations are apparently caused by damage to a portion of the DNA molecule or by defective replication.
The other important property of genes is the control of developmental processes. All living organisms are composed of protein chains built out of simpler building blocks, the twenty amino acids. The DNA remains in the cell nucleus, but its distinctive sequences are copied on single strands of messenger-RNA and carried to other parts of the cell, where amino acids are assembled into protein chains. It was found that there is a genetic code in which a distinctive group of three bases corresponds to each of the twenty amino acids. The order of the triplets in the DNA determines the order in which the amino acids are assembled into protein chains.
In the DNA, then, an "alphabet" of just four "letters" (A, C, G, and T bases), grouped in three-letter "words" (each specifying one of the amino acids), is arranged in "sentences" (specifying particular proteins). Thousands of sentences of varying length and word order can be made from the twenty basic words, so there are thousands of possible proteins. Long paired strands, made of exactly the same four bases in various sequences, constitute the genes of all organisms, from microbes to human beings. In all known organisms, the same code is used to translate from DNA to protein, which seems to indicate a common origin for all living things.
The origin of life remains a mystery, but some possible pieces of the puzzle have been proposed. In 1953, Stanley Miller passed sparks through a flask containing only a mixture of simple gases and heated water (the inorganic compounds that were probably present in the early atmosphere and ocean). He found that he had produced many of the amino acids. Other scientists detected the spectra of simple organic compounds in interstellar gas clouds, and amino acids were found inside meteorites arriving from outer space. Glycine was the most abundant amino acid in both the Miller experiments and in the meteorites, as it is in living organisms. Alanine was second in all three cases. Perhaps the earliest forms of life arose in such a prebiotic soup. More complex proteins can form microspheres, which in some cases grow and split into two smaller spheres, resembling rudimentary cells.15
An alternative theory proposes that a primitive form of replication occurred first in crystals of clay or other minerals. For a given mineral, one of the alternative crystal structures, and whatever flaws are present in it, is copied onto successive layers. A small piece of mineral dust, dropped in a supersaturated solution, acts as a "seed" around which a new crystal grows, replicating the flaws in the original. If some versions survive better than others, there would be a rudimentary selection system. Certain organic molecules are known to facilitate such crystal replication. Perhaps organic molecules at first assisted inorganic replication and later achieved self-replication on their own.16
But how could DNA and the genetic code have arisen? The coding molecules in an organism today are themselves the product of coded instructions. We seem to face a chicken-and-egg dilemma, as far back as we go. But Manfred Eigen has shown that if you string nucleotide bases together, some combinations are more stable than others. There could have been an early form of chemical evolution, a prebiological selection of more stable combinations. The most stable and abundant triplet, GGC, corresponds to the simplest and most abundant amino acid, glycine. GCC is second in abundance; it corresponds to alanine, also second. Eigen proposes a hypothetical "hypercycle" of four simple RNA chains, which could replicate and also synthesize proto-proteins.17 This would still be a long way from DNA, and much remains puzzling, but the gap between nonliving and living forms does not seem as wide as it did a few decades ago.
It has often been assumed that the Second Law of Thermodynamics excludes the emergence of more highly ordered states, since entropy or disorder tends to increase in closed systems. But I pointed out in chapter 4 that organisms are open systems, citing Prigogineís work on the appearance of more complex patterns of order in physical systems far from equilibrium. In discussing the origins of life, Jeffrey Wicken has shown that self-organizing dissipative systems can contribute to the production of entropy in irreversible energy flows. The accumulation of organization and structure provides boundary conditions on the operation of physicochemical processes; there is randomization within constraints. The given chemical affinities and bonding preferences provide internal limitations on structural possibilities. Wicken observes that to explain a state in classical physics, one needs only a set of initial conditions and a set of laws. But to explain a state in the biological world, one needs a historical account of change and cumulative selection. Moreover, an organism is selected as part of a total ecosystem that constitutes a flow of energy and materials. Wicken argues that evolutionary explanations must be holistic in both time and space.18
4. DNA, Information, and Systems Theory
The evolutionary role of DNA as an encoded message is illuminated by work in information theory. In chapter 4 we saw that order and information are represented by improbable combinations of components. Entropy and disorder tend to increase in a closed system, leading to a loss of information. During World War II interest grew in the reliable communication of messages by radio. In that context, noise is disorder that degrades a message. According to information theory, there are two ways of reducing such loss: (1) redundancy, in which portions of the message are repeated, and (2) rules, which set constraints by restricting the allowable combinations, while still allowing novelty and diversity. All languages have spelling rules for combinations of letters and grammatical rules for combinations of words.
Information in living organisms is preserved in the same two ways. There is considerable redundancy in the sequences of DNA in the genes. There seems to be redundancy in the storage of information in the brain, since people can undergo considerable brain damage without loss of memory or function. In perception, too, reliability is increased by redundancy. The genes themselves seem to have internal structural rules that limit the possible combinations and restrict the operation of chance, though here we know more about the alphabet than about the grammar. Yet there is ample opportunity for novel messages. For evolution to occur, mutations must be neither too rare nor too frequent. Jeremy Campbell writes, "The lesson of information theory is that choice and constraint can coexist as partners, enabling a system, be it a living organism, a language, or a society, to follow the arrow not of entropy but of history."19
For evolution to occur information must flow in two directions, both from and to the genes. Consider first the expression of the DNA in the growing organism. The linear message of the DNA molecule produces a linear protein chain, but because there are characteristic bonding angles and folds in the chain, the result is a distinctive three-dimensional protein structure, with sites for side groups. Message leads to structure, and structure leads to function. A very complex set of genetic regulatory programs with activators and repressors switches the activity of other genes on and off, so that the right kind of cell is produced at the right place and at the right time in the growing embryo and in the continuing functioning of the organism. In this context, the DNA embodies effective information, that is, a set of instructions.
Information about the environment is also transmitted to the gene pool There is information on what has proved viable and how the organism can make its way through the world, including encoded instinctive behavioral patterns. This represents a memory capacity through which the story of life is written in the DNA. We could say that the system shows a kind of learning ability, a trial-and-error testing in a series of information gathering experiments reaching up to larger units: organisms, populations, and ecosystems. Considerable unused information is stored in the DNA, which can be called on under altered environmental conditions. Here is a cybernetic or feedback system for gaining, storing, retrieving, and using information. The action of DNA is context-dependent and requires a two-way flow of information between levels. Information, along with matter and energy, is thus a basic constituent of reality, and it is relational in character. Words convey a message only when they are read. Information is context-dependent.
Imagine a person writing a book that is organized in chapters, paragraphs, sentences, words, and letters. The choice of letters is determined by the choice of words, and the words are governed by the formulation of sentences, and so forth. The writer also assumes a whole set of encoding conventions: grammatical rules, linguistic practices, and the alphabet and vocabulary of a particular language-using community. The reader, in turn, uses the same rules to decode the message. The book can be translated into another language, or it can be read aloud, expressing the same message in another medium.
In the case of DNA, too, the meaning of the part depends on larger wholes. Control sequences (operons) regulate whole blocks of activities. Recognition codes provide responses to particular molecular structures. Developmental pathways aid the differentiation and growth of cells in particular organs. Homeostatic feedback mechanisms, such as those for temperature regulation, represent norms for the functioning of the organism as a whole. In each case the patterns among components at one level set boundary conditions for activities at lower levels, The patterns in the DNA do not violate the laws of physics and chemistry, but they could never be deduced from those laws. Information is recorded and utilized in hierarchically organized patterns. The meaning of the parts is determined relationally and contextually by their participation in larger wholes.20 A similar hierarchical ordering is present in computer programs. In that case, too, the message (software) can be distinguished from the medium (hardware). We will examine computers and the Information Revolution in the next volume.
DNA constitutes a developmental and functioning program only in conjunction with molecules in the cytoplasm, which provide a milieu and support structure. The genetic program has been preserved from the past and functions in the present because of the behavior of larger units -- including, finally, the whole interdependent ecosystem with its cycles and interactions of energy, materials, and information. Each unit achieves stability by being nested in a larger whole to whose stability and dynamism it contributes. As Wicken puts it, "Nature produces itself hierarchically -- one level establishing the ground of its own stability by utilizing mechanisms made available by lower levels, and finding functional contexts at higher levels."21
The relation among levels of order has been analyzed in systems theory, especially in hierarchy theory. Information theorist Herbert Simon asks us to imagine a watchmaker whose work is disrupted occasionally. If the watchmaker has to start over again each time, he may never finish his task. But if he assembles groups of parts in stable subassemblies, which are then combined, he will finish the task more rapidly. Living organisms have many such stable subassemblies, with differing bonding strengths, which are preserved intact and only loosely coupled to each other. The higher level of stability often arises from functions that are relatively independent of variations in the microscopic details. The collective integrated behavior can be described in a simpler way at a higher organizational level.22
Here is a clue as to how evolution can exhibit both chance and directionality. Chance is present at many levels: mutations, genetic recombination, genetic drift, climatic variations, and so forth. Evolution is an unrepeatable series of events that no one could have predicted; it can only be described historically. Yet history has seen an ascent to higher levels of organization, a trend toward greater complexity and sentience. The dice are thrown, but the dice are loaded; there are built-in constraints. In particular, modular structures are relatively stable, and so the advances are conserved. Think of a gear that can make small random rotations in either direction. If it has a ratchet that occasionally clicks in place, rotation in one direction will be favored in the long run. Another analogy is a ball on a hill with small terraces, offering "metastable states" in which the ball can rest without returning to the bottom.
There are two kinds of hierarchy. First, considered historically, is genealogical hierarchy: gene, organism, and species. The units are identified by their historical role in replication and evolutionary change. Second, considered at any point in time, is an organizational hierarchy: atom, molecule, cell, organ, organism, population, and ecosystem. Here units are identified by their relative stability and their action and interaction as integrated units. Entities at any level share many properties with other entities at that level and share relatively few properties with entities at other levels. In both hierarchies information flows between levels. In the second case, Niles Eldredge and Stanley Salthe speak of an "upward influence" when many lower-level subsystems work together as necessary conditions of a larger whole, and a "downward influence" when many subsystems are constrained by the boundary conditions set by higher-level activities.23 How are these hierarchical levels related to each other?
II. A Hierarchy of Levels
Francis Crick, the co-discoverer of the structure of DNA, has written: "Thus eventually one may hope to have the whole of biology Ďexplainedí in terms of the level below it, and so on right down to the atomic level. . . . The knowledge we have already makes it highly unlikely that there is anything that cannot be explained by physics and chemistry."24 The spectacular success of molecular biology has sometimes been taken as support for such reductionist claims. We will consider several forms of reductionism and then reply to them by defending a hierarchy of distinctive levels, both in evolutionary history and in the activity of organisms today. The discussion here is philosophical, but it involves the interpretation of biology. Theological issues are taken up in section III.
1. Three Forms of Reduction
Three forms of reduction can be distinguished:25 (1) methodological reduction as a research strategy; (2) epistemological reduction as a relation between theories; and (3) ontological reduction as a view of reality. They can be distinguished because they make different kinds of claims, though many authors shift uncritically from one to another.
1. Methodological Reduction. A Research Strategy
It is often a useful research strategy to study a complex whole by breaking it up into more manageable component units. In particular, the analysis of molecular structures and interactions has been a powerful tool in biological research. One could adopt reduction as a practical research strategy without claiming that all biological theories will be derived from chemical theories, or that nothing exists in the world except material particles.
If, however, methodological reduction is held to be the only valid research strategy, it can lead to the exclusion of synthetic or "compositionist" approaches, in which more inclusive wholes are studied. Some have feared that the bandwagon of interest in molecular biology would lead to the neglect of fields that deal with the whole organism, such as population genetics, embryology, ecology, and animal behavior. The biologist Clifford Grobstein makes a plea for multilevel analysis: "Sophisticated biological investigation thus involves a cross-feed of information between analyses proceeding at several levels."26 Another biologist, Ernst Mayr says that dissection into components is helpful because processes at different levels are in some respects independent, but it is inadequate because these processes are also interdependent.27
Alexander Rosenberg, a philosopher of science, holds that lower-level regularities are often too complex to allow the prediction of higher-level regularities. In practice, higher-level relationships must be investigated in their own terms. Biology is often organized around functions that can be identified only in relation to larger units and activities.28 Moreover, randomness at one level often has no connection with randomness at another level (for example, the pairing of mates in a population and the combination of genes from a particular pair). Methodological reduction may be accepted, then, as long as it does not lead to the neglect of research programs at a variety of levels, from molecules to ecosystems.
2. Epistemological Reduction: A Relation Between Theories
Here the claim is that the theories or laws of one level can be derived from those of another level. For examples the laws relating the volume, pressure, and temperature of a sample of gas can be derived from the mechanical laws governing the motion of molecules (if temperature is identified with the average kinetic energy of the molecules). According to the philosopher Ernest Nagel, there are two conditions for the reduction of one theory to another: (1) the connectability of all concepts in the two theories, and (2) the derivability of one set of theoretical statements from the other. Nagel shows that many biological concepts cannot be defined in chemical terms.29 In the same vein, another philosopher, Morton Beckner, maintains that there are distinctive biological concepts, referring to the functioning of higher-level units, that cannot be translated into the concepts of physics and chemistry. Integrative functions are not specifiable by terms referring to the parts alone.30
Biologists have also upheld the distinctiveness of biological concepts. Francisco Ayala lists fitness, adaptation, predator, organ, heterozygosity, and sexuality among the biological concepts that cannot be translated into statements about molecules. Mayr claims that the uniqueness and unpredictability of evolutionary events can be described only by historical narrative, not by any set of lawful regularities. Genetic information can be accounted for only historically; particular sequences of DNA cannot be deduced from chemical laws. Moreover, the description and explanation of the behavior of organisms in terms of teleological categories (goals and purposes) will always be useful because there are diverse means to reach a particular goal.31
Looking at the history of modern biology, Lindley Darden and Nancy Maull argue that interlevel theories were introduced as new hypotheses that could not have been derived from the theories of either field. They describe a field of inquiry as a set of distinctive theories, problems, techniques, and vocabularies. The connections between the vocabularies of differing fields were first advanced as imaginative hypotheses. For example, in 1904 it was postulated that genes (unobserved theoretical entities by which geneticists accounted for observed hereditary variations) are located in the chromosomes (dark-stained filaments observed by cytologists in the study of cell nuclei). In the 1950s, the genes of genetic theory were identified with DNA structures (molecular configurations studied by biochemists) through the hypothesis that DNA controls developmental growth Jacob and Monodís operon theory of regulatory genes (1961) and subsequent research on the role of enzymes in protein synthesis elaborated on this hypothesis. The research was a response to questions that could not be answered in either genetics or molecular biology alone, and it led to concepts different from those in either field at the time. Darden and Maull suggest that the unity of science is an important goal, but it is not achieved by theory reduction:
An interfield theory, in explaining relations between two fields, does not eliminate a theory or field or domain. The fields retain their separate identities, even though new lines of research closely coordinate the fields. . . . It becomes natural to view the unity of science, not as a hierarchical series of reductions between theories, but rather as the bridging of fields by interfield theories.32
3. Ontological Reduction: A View of Reality
Here an assertion is made, not about research strategies or the relation between theories, but about the kinds of things that exist in the world. When it is stated that organisms consist of "nothing but atoms," a metaphysics of materialism and atomism is asserted. It is assumed that the true nature of an entity is manifest at its lowest level.
Materialism among modern biologists is partly a reaction to vitalism, in which life was held to be a special nonmaterial principle or agency. In the 1930s, Driesch interpreted experiments in embryology as evidence of a vital agent within the developing embryo, a purposeful "entelechy" which adjusts processes to achieve a future goal in spite of obstacles (for example, a newt can grow a new limb after an amputation). But the idea was vague and offered no testable hypotheses for particular cases, so it has been scientifically useless. Moreover, there is no clear line between living and nonliving forms (viruses, for instance, share characteristics with both). Vitalism has almost no advocates today, but the desire to avoid it has swayed many biologists toward a materialistic metaphysics.
Organicism seems to be a compromise between materialism and vitalism, but at crucial points it differs from both. Here life is understood as a type of organization and activity, not a separate nonmaterial entity or substance. There is no impassable gulf between the living and the nonliving (either in evolutionary history or among present forms), but rather a continuity of interdependent levels. Organicists oppose epistemological reductionism and defend the distinctiveness of biological concepts, but they go further in asserting that organismic concepts refer to aspects of the real world. If an organism is an integral whole with a hierarchy of levels of organization and activity, one can defend the distinctiveness of biological processes. Processes at one level are not fully determined by those at lower levels, and yet there is no violation of the laws governing processes at lower levels.
2. Levels, Emergence, and Wholes
We must look further at the distinction between levels of analysis (an epistemological concept) and levels of organization and activity (ontological concepts).
1. Levels of Analysis
Every field of inquiry is limited by its conceptual tools. Any set of concepts is abstractive and selective, representing a particular way of simplifying complex phenomena. Complementary models may sometimes be helpful in analyzing phenomena at a given level. Diverse models are employed on differing levels, and noneí gives an exhaustive account. Higher-level theories are heuristically useful in correlating features of the integrated behavior of larger wholes, even when interlevel theories have been developed. Instrumentalists would uphold the value of theories at a variety of levels without making claims about the existence of levels in nature.
2. Levels of Organization and Activity
The philosopher William Wimsatt holds that nonreducible concepts with many links to observations should be given an ontological but revisable status as "candidates for reality." Differing levels of analysis reflect real structures in the world, though in a limited and partial way.33 The critical realism that I defended in earlier chapters would allow for ontological as well as epistemological levels, that is, a multileveled view of reality. Organicism postulates significant differences among levels but without the sharp breaks and dualistic contrasts portrayed by vitalism. Nature consists of relatively stable strata within a continuous spectrum of complexity. Levels of organization specify structural relationships. Levels of activity specify events and processes.
A hierarchy of functional processes is always closely correlated and integrated with a hierarchy of structural parts. In a systems framework, the parts are identified, conceptualized, and related to one another through their roles in functionally construed processes. On the other hand, the functions are fulfilled through the interaction of the parts. These are complementary rather than competing ways of describing the same system. Stephen Toulmin writes, "Indeed, the very organization of organisms -- the organization that is sometimes described as though it simply involved a Ďhierarchyí of progressively larger structures -- can better be viewed as involving a ladder of progressively more complex systems. All these systems, whatever their level of complexity, need to be analyzed and understood both in terms of the functions they serve and also of the mechanisms they call into play."34
Evolutionary history has seen the emergence of novel forms of order and activity that could not have been predicted from previous forms. The evolutionary account is inescapably historical rather than deductive in character because there is both chance and emergence in nature. When, successively, molecules, cells, and organisms appeared, they brought new properties and kinds of behavior. New forms of purposive behavior and mental life finally blossomed into consciousness and then self-consciousness.
A two-way interaction of wholes and parts occurs at many levels. We saw the importance of wholes already at the quantum level, as evident in the Pauli Exclusion Principle and the Bellís Theorem experiments. The atom must be viewed as a total vibratory system; the electron is more like a state of the system than a separate individual entity. In an ecological view of living things, every entity is considered within a hierarchy of more inclusive wholes. Interlevel theories often describe the behavior of parts in forming wholes. In process philosophy, relationships are constitutive of every entity; relations are internal rather than only external to its being.
Wholes of diverse types are conveniently represented by the flexible term societies. The process philosopher Charles Hartshorne calls an organism "a society of cells." In some societies (for example, a pile of sand grains) all members are of the same grade and there is almost no overall structure; the whole has less unity than each of its parts. Other societies consist of loose aggregates (for example, a sponge or even a tree) whose parts are relatively independent. An ant colony has some coordination and division of labor but no central agent. Other societies are well-unified wholes with radically dominant members and complex internal organization. Even in a human being, however, each cell has considerable independence; various organs and subsystems (heart, endocrine system, and so forth) function apart from any conscious control. Only with the growth of the nervous system is the unification of the experience of the whole organism achieved.35
The degree of subordination of part to whole thus varies widely. In the hierarchy of levels, the organism is the unit of reproduction and usually has a more complex integrative organization than levels above or below it. But there is great diversity in the kinds of integration that can occur at any of these levels. Consequently, there are variations in the extent to which a part preserves or loses its autonomy when it contributes to a larger whole. In general, an activity at any level is influenced by patterns of activity at both higher and lower levels. In this sense one can say that part and whole mutually influence each other, without implying that the whole is somehow an entity existing independently of the parts.
Michael Polanyi points out that a machineís design imposes boundary conditions on chemical and physical processes. The laws of physics and chemistry are not violated, but they are harnessed for organized functions. He suggests that the morphology and structure of an organism similarly constitutes boundary conditions that are not required by biochemical laws but are compatible with such laws.36 In the case of the machine, of course, it is the human designer who "harnesses" the laws, and the behavior of the whole machine is similar in character to that of the parts, so the analogy is rather limited. Donald Campbell gives a more complex analysis of the downward causation through which processes at lower levels are constrained by relationships at higher levels. For example, the huge jaws of the soldier termite are the developmental product of its DNA, but the DNA is itself the product of the selection of the whole organism in its dependence on the termite colony. (The jaws are so large, in fact, that it cannot feed itself and has to be fed by worker termites.)37 In the world of organisms a complex interaction takes place among levels.
3. Sentience and Purposiveness
The sentience of simple organisms is a minimal responsiveness to the environment but sentience takes increasingly complex forms. Perception is the selective transmission of information about the environment. Even elementary sense organs can detect features of the environment relevant to the organismís life. Perception is an active process in which patterns important to its survival are picked out and organized. Responsive action is possible because sensations derive from an external environment and are taken to refer to it. A one-celled paramecium has a crude nervous system and a rudimentary form of memory. If it finds no food at one location it will not persist there but will use its coordinated oarlike hairs to move to another location. Short-term memory requires a new way of storing and recalling information, different from storage in the genes.
Sentience also seems to involve an internal dimension, a center of perception and action, some sort of elementary awareness and feeling. By the time a central nervous system appeared, there was a coordinating network and a new level of integration of experience, which developed eventually into consciousness and finally self-consciousness. We can try to imagine the awareness in higher animals and perhaps even that in lower vertebrates, but we can hardly imagine the rudimentary experience of invertebrates.
Sentience at even low levels seems to imply at least an elementary capacity for pain and pleasure. When a neural system is present, pain serves as an alarm system and an energizing force by which harm can be avoided. The capacities for both pain and pleasure were presumably selected for their high survival value. The behavior of animals gives evidence that they can suffer intensely. It seems likely that there is suffering in lower creatures, but with much less intensity.38
Some forms of goal-directedness can occur in the inanimate world. A simple sensor and activator (such as a thermostat and furnace) can be connected as a control system, a self-regulating feedback mechanism that compensates for deviations from a steady state. A self-guiding missile "seeks its target" by modifying its flight in response to reflected radar signals; it has a limited flexibility of response to changing external conditions. But many organisms show much greater flexibility in actions to achieve a goal under varying conditions. This goes beyond the cybernetic model of a goal as a source of guiding signals. An animal may seek food when there is none and may do so in ways not previously attempted. Memory of past sequences and their outcomes leads to the anticipation of future occurrences, which serve as goals of present behavior. Animals and birds can devise novel and circuitous means of achieving an end, indicating an orientation toward the future and showing imagination in devising new ways of circumventing obstacles.39
Various forms of animal and insect behavior suggest the presence of purposiveness and anticipation. Some foresight is evident even amid largely instinctive actions. If a wasp encounters difficulties in building a nest, it will show limited ingenuity in devising new sequences of actions to complete the task. A rat deciding between two paths, in one of which it will receive an electric shock, hesitates as if imaginatively anticipating future consequences. Donald Griffin, Stephen Walker, and others have written about animal awareness. They have portrayed the evolutionary continuity of mental experience, the survival value of consciousness, and the development of higher levels of perception, memory, intelligence, and communication.40
How far down the scale of life can such concepts be extended? W. E. Agar and Bernhard Rensch suggest that all organisms should be considered as feeling, experiencing subjects, even at a rudimentary level.41 The biologist Sewall Wright argues that in the spectrum of behavior from higher to lower organisms there is no discontinuity; since we cannot draw a line at any point, we must assume the universal presence of something akin to mind. There is no discontinuity in the development of minds from simpler structures in either the history of the world (evolution) or of the individual (embryology). "The emergence of even the simplest mind from no mind seems to me utterly incomprehensible." Wright concludes that at all organic levels an entity is mind to itself and matter as viewed by others. The unique creativity of each individual event and its essential nature as will or mind inevitably escapes the scientist, who deals only with regularities and sees only the external side of things.42 I am dubious about such attribution of mind to low-level organisms but I will argue for the attribution of elementary forms of experience.
In discussing process philosophy (chapter 8), I will suggest that unified entities at all levels should be considered as experiencing subjects, with at least rudimentary sentience, memory, and purposiveness. This will require reference to levels of experience as well as levels of activity. I will argue that we must recognize the emergence of distinctive forms of activity and experience at higher levels; mind and consciousness appear only at higher levels, and a developed self-consciousness only in human beings.
III. Theological Implications
As we turn to the theological implications of evolution, we ask first about the relation of chance to design. Some models of continuing creation are then explored. Finally, several kinds of theological response are considered.
1. Chance and Design
Is evolution a directional process? History indeed shows a general trend toward greater complexity, responsiveness, and awareness. However, when viewed locally and over shorter periods there seem to be many directions of change rather than a uniform stream. Short-term opportunism fills temporarily unoccupied ecological niches, which may turn out to be blind alleys when conditions change. There is no evidence of foresight in looking to future needs. Gould gives examples in which a structure originally filling one function was adapted for another function in a makeshift way. For instance, the pandaís thumb developed from a bone and muscles in the wrist, a far from perfect design.43 In some cases we see retrogression, as when a formerly independent organism becomes a parasite. And, of course, by far the majority of species have ended in extinction.
We have seen the pervasive role of chance in evolution, from mutation and genetic combination to unpredictable changes in environments. Evolutionary history is irreversible and unrepeatable. Potentialities that were present at one point were permanently excluded by particular lines of development. Most mutations are harmful to the organism, or even lethal. Monod believes that the prevalence of "blind chance" shows that the existence of all organisms is accidental and not the product of design. It is a meaningless universe in which we alone arbitrarily introduce any meaning in human life.44
Fred Hoyle and Chandra Wickramasinghe, on the other hand, argue that the origination of any particular protein molecule by chance is inconceivably improbable. If there are twenty different amino acids and one wants to construct a protein chain of one hundred amino acids, the number of possible combinations is enormous. If you shuffled them at random a billion times a second, it would take many times the history of the universe to run through all the combinations.45 The argument is dubious, however, because there are specific attractive forces, and the various combinations are not equally probable or equally stable. As we said, the dice are loaded. As larger structures are formed, metastable states are likely to persist. Complexity comes into being by hierarchical stages, not in one gigantic lottery. Once there is reproduction, natural selection is an antichance agency, preserving highly improbable combinations through successive generations. Evolution shows a subtle interplay of chance and law.
In evolution we have to look at chance, law, and history. In a roulette wheel or a kaleidoscope, law and chance are both present in ever-changing patterns, but there is no historical memory, and the past is irrelevant to the future. But in natural history, earlier achievements get folded into the developmental levels of later organisms because they have left a record in the genes. The memory of the past contributes to the present and the future. Evolutionary historicity involves unpredictability, irreversibility, and memory. Even the general trends cannot be predicted from scientific laws but can only be described in historical narratives. John Maynard-Smith writes, "There is nothing in neo-Darwinism which enables us to predict a long-term increase in complexity."46 Gould states, "Natural selection is a theory of local adaptation to changing environments. It proposes no perfecting principles, no guarantee of general improvement."
Traditionally, design was equated with a detailed preexisting blueprint in the mind of God. Theologians since the church fathers were influenced by the Platonic view of an eternal order of ideas behind the material world. God was said to have a foreordained plan, which was carried out in creation. In this framework, chance is the antithesis of design. But evolution suggests another understanding of design in which there are general directions but no detailed plan. There could be a long-range strategy combined with short-range opportunism arising from feedback and adjustment. In this strategy, order grows by the use of chaos rather than by its elimination. There is improvement but not perfection. There is increasing order and information but no predictable final state.48 Robert Russell urges us not to equate disorder (entropy) with evil, or order with the good, for disorder is sometimes a precondition for the emergence of new forms of order. He cites Prigogineís work on systems far from equilibrium as an example of disorder that leads to novel structures. More generally, new life is possible only because of the death of the old. Pain, suffering, and the challenge of crises can contribute to growth.49
D. J. Bartholomew points out that human beings can use chance to further their purposes. We toss a coin in the interest of fairness, and we seek random samples in making representative surveys. Many games combine skill and chance; by shuffling cards we generate variety, surprise, and excitement. In evolution, he says, variety is a source of flexibility and adaptability. Varied populations can respond to changing circumstances better than monocultures, and of course genetic variation is essential for evolutionary change. Chance and law are complementary rather than conflicting features of nature. Random events at one level may lead to statistical regularities at a higher level of aggregation. Redundancy and thresholds may limit the effects of random events on integrated systems. On this reading, chance would be part of the design and not incompatible with it.50
Thus three theological responses to chance are possible.
1. God controls events that appear to be random. Perhaps events are determined by God, though to us there seems to be an element of chance. This would be like Einsteinís view that quantum uncertainties are merely a reflection of human ignorance; but here it would be a hidden divine action rather than hidden natural causes that exactly determines every event. We looked earlier at Pollardís suggestion that God controls all subatomic indeterminacies. Pollard extends the idea to the claim that apparently chance events in evolution are predestined by God. The "accidental" or "coincidental" intersection of two unrelated causal chains may also have been providentially arranged.51 Donald MacKay and Peter Geach similarly maintain that every microevent is divinely directed, without violation of the long-run statistical laws which science has discerned.52
But this view seems vulnerable to the objections of Gould and others that it is hard to imagine that every detail of evolutionary history is the product of deliberate intelligent design. There have been too many blind alleys and extinct species and too much waste, suffering, and evil to attribute every event to Godís specific will. Another objection to this view is that it is implicitly reductionistic in assuming that God enters mainly at the lowest level (in atomic or molecular uncertainties). In Pollardís view, God acts on larger wholes and higher levels "from the bottom up" rather than "from the top down."
2. God designed a system of law and chance. This was Darwinís view in the letter quoted earlier. Earlier in this century, several authors portrayed design, not in particular biological phenomena, but in the systematic conditions that made life and consciousness possible. L. J. Henderson described the many chemical and physical properties that are favorable for the existence of life. Carbon, for example, has a unique place in the organic world because of its variety of multiple bonds. Henderson combined a teleological view of nature as a whole with a mechanistic view of its processes.53 F. R. Tennant elaborated a "wider teleological argument" based on the conditions of distinctively human existence and the interconnectedness of matter, life, and human personality.54 The arguments here are like those of the Anthropic Principle in relation to the early universe, but they deal more specifically with organic and human life. We have seen that the structures of DNA and proteins are dependent on incredibly complex combinations of inter-atomic forces and bonding angles. There is no reason to think that just any combination of forces would have led to life and consciousness. Design is identified with the lawful structures of the world, which make higher-level activities possible.
Recent authors point to both chance and law as expressions of Godís overall design of the universe. Thus Polkinghorne writes, "The actual balance between chance and necessity, contingency and potentiality which we perceive seems to me to be consistent with the will of a patient and subtle Creator, content to achieve his purposes through the unfolding of process and accepting thereby a measure of the vulnerability and precariousness which always characterize the gift of freedom by love." For Polkinghorne, God is "the ground of physical process, not a participant in it." Here the problems of waste, suffering, and human freedom are less acute, for only the general system and not the details of particular events are expressions of Godís will. Insofar as chance is really present, the predestination of every event cannot be accepted. God designed a system whereby law and chance could lead to life and mind and the diverse dimensions of human experience. God does not interfere with the system. But the theologian may object that in this interpretation Godís role is limited to originating and sustaining the natural process. We have a world that is more complex and unpredictable than the Newtonian world machine, but we still seem to end with an inactive God like that in deism.
3. God influences events without controlling them. This resembles the second view in rejecting predestination and acknowledging genuine chance in the world. But it resembles the first view in giving God a continuing active role, though a limited one. Chance, lawful causes, and God enter the constitution of each event. Godís purposes are expressed not only in the unchanging structural conditions of life, but more specifically in relation to changing situations and patterns. Continuing creation, in this view, is a trial-and-error experiment, always building on what is already there. Evolutionary history has involved suffering and waste throughout, but it has resulted in the appearance of varied and valuable forms of experience. There are risks that the experiment might fail on this planet. Human folly may yet lead to a nuclear holocaust in which civilization, and perhaps the human species itself, does not survive.
The zoologist Charles Birch maintains that evolutionary history resembles a vast experiment. It is an unfinished universe, a world in birth, a dynamic process of trial and error. Struggle and suffering, accident and chance, uncertainty and risk are never absent. He holds that we must imagine a continuous and flexible creativity in the process, not an omnipotent designer executing a preconceived plan. For Birch this suggests the Whiteheadian God of persuasive love rather than coercive power, a God who influences and is influenced by the world, who allows freedom in humanity and spontaneity in nature, and who is involved in the world and participates in its slow growth. Birch adopts Whiteheadís view that all entities have an inner aspect; every entity is considered a center of at least rudimentary experience.56
2. Models of Creation
Before looking at some doctrines that theologians have discussed in relation to evolution, let us consider some theological models. Models, I suggested earlier, are less conceptually precise than doctrines but more powerful in personal religious life and communal liturgy.
The Bible itself includes a variety of models of God as Creator. Some of these were indicated in the previous chapter. In Genesis, God is a purposeful designer imposing order on chaos. Godís command is powerful and the divine Word is effective. Other biblical images picture a potter forming an object (Jer. 18:6, Isa. 64:8) or an architect laying out the foundations of a building (Job 38:4). God is Lord and King, ruling the universe to bring about intended purposes. The world is a manifestation of Godís Word and an expression of divine Wisdom, which communicates meaning. In the New Testament, God creates through the Word (John 1), a term that, we have seen, brings together the Hebrew concept of divine Word active in the world and the Greek concept of Word (logos) as rational principle. The purpose of creation is made known in Christ, the Word incarnate. Here is a rich diversity of models, each a partial and limited analogy, highlighting imaginatively a particular way of looking at Godís relation to the world.
The potter and craftsman analogies assume the production of a completed, static product. They seem less helpful in thinking about an ongoing, dynamic process. The image of God as gardener is more promising, though it occurs rarely in the Bible (for example, Gen. 2:8), perhaps because the Israelites wanted to distance themselves from the nature gods of surrounding cultures. The analogies of God as King and Ruler were emphasized in medieval and Calvinist thought. But the doctrines of omnipotence and predestination to which they led are difficult to reconcile with the current scientific view of nature.
In the Bible, the model of father is used for Godís relation to persons, but there is also a fatherly care for nature (for example, the birds and lilies of Matt. 6:26). God as mother was a rare image in a patriarchal society, but it appears occasionally (for example, Isa. 49:15 and 66:13). The parental analogy is usually drawn from a parent nurturing a growing child rather than from procreation and birth. This seems a particularly appropriate image of Godís relation to the world; the wise parent allows for an increasing independence in the child while offering encouragement and love. Such an image can maintain a balance between what our culture thinks of as masculine and feminine qualities, in contrast to the heavily "masculine" monarchical model of omnipotence and sovereignty.
The biblical image of God as Spirit seems to me particularly helpful. Here the analogy is the distinctive vitality, creativity, and mystery of the human spirit. The human spirit is the active person as a rational, feeling, willing self responding to other persons and to God. In the previous chapter, I pointed out the reference to the Spirit in creation (Gen. 1:2) and in the continuous creation of the creatures: "When thou sendest forth thy Spirit, they are created" (Ps. 104:30). The Spirit also represents Godís activity in the worshiping community and in the inspiration of the prophets. I will propose in the next chapter that we can think of Christ as having been inspired by the Spirit. The idea of the Spirit allows us to bring together our understanding of God as Creator and as Redeemer.
Among contemporary theologians, Conrad Hyers has asked what models of creation are compatible with a world of order and chance. He suggests that the combination of intention and unpredictability in an artistís interaction with a medium provides an apt analogy. Again, God is like a poet or dramatist in whose work there is both plan and surprise, or like the writer of a novel whose plot shows both coherent unity and the novelty of the unexpected.57
Arthur Peacocke has written extensively about models of God in an evolutionary world. Of classical models he find Spirit and logos most suitable for expressing immanent divine creativity. God is the communicator, conveying meaning through the patterns of nature as well as through the person of Christ. Peacocke also uses many striking new images, some of which are systematically developed as models. One is the mind/body relation as an analogy for Godís relation to the world. The world might be thought of as Godís body, he suggests, and God as the worldís mind. We can look on cosmic history as the action of an agent expressing intentions,58 This is indeed a promising model, but it raises several questions. Does the analogy presuppose a mind/body dualism? Does the world have as much unity and coordination as the body of an organism? Can the mind/body model represent the pluralism and partial independence of individual beings in the world?
Peacocke also mentions briefly the alternative model of a pregnant mother bringing a baby into being within her body.59 This seems to represent a degree of unity intermediate between that of a motherís relation to her own body, on the one hand, and that of her relation to a growing child after birth, on the other. I am inclined to favor the growing child analogy. I will suggest that the social model of process thought is able to preserve the separate identity of both God and individual creatures, along with a recognition of their interdependence and relatedness.
Noting the unpredictability of evolutionary history, Peacocke says God is like the choreographer of an ongoing dance or the composer of a still-unfinished symphony, experimenting, improvising, and expanding on a theme and variations. Peacocke uses other analogies that assign a positive role to chance. Chance is Godís radar beam sweeping through the diverse potentialities that are invisibly present in each configuration in the world.
Chance is a way of exploring the range of potential forms of matter.60 God has endowed the stuff of the world with creative potentialities, which are successively disclosed. The actualization of these potentialities can occur only when suitable conditions are present. Events occur not according to a predetermined plan but with unpredictable novelty. God is experimenting and improvising in an open-ended process of continuing creation. Peacocke rejects the idea of omnipotence and speaks of the self-limitation of a God who suffers with the world.
Peacocke writes that "the natural causal creative nexus of events is itself Godís creative action." He holds that processes of nature are inherently creative. This might be interpreted as a version of the second option outlined above: God initially designed a system of law and chance, through which higher forms of life slowly came into being. This would be a sophisticated form of deism. But Peacocke also says that God is "at work continuously creating in and through the stuff of the world he had endowed with those very potentialities."61 The images of an improvising choreographer or composer imply an active, continuing relationship with the world. Peacocke specifically defends the idea of continuing creation. This would put him closer to the third option above, but he does not develop a systematic metaphysics to describe this ongoing interaction between God and the world.
3. Creation and Evolution: Three Views
We can make an interim assessment of some theological positions concerning creation and evolution, using the basic classification scheme of chapter 1: Conflict, Independence, and Dialogue. The fourth option, Integration, is discussed in the concluding section.
1. Conflict Between Creation and Evolution
The first version is scientific materialism, In chapter 1, I cited Monod and Wilson and criticized the reductionism and materialism of their metaphysics. A more recent example is Richard Dawkinsís The Blind Watchmaker, which has the subtitle Why the Evidence of Evolution Reveals a Universe without Design. Much of the book is a clear and forceful presentation of current evolutionary theory and a defense of orthodox neo-Darwinism against its scientific critics. He also replies to the argument that the various parts of the eye could not be products of separate chance variations because one part would be useless without all the other parts. Dawkins shows how the eye and other organs could have arisen from many independent small improvements. A light-sensitive cell or a very simple eye is better than nothing. He provides a lucid discussion of the collaboration of genes in embryonic development.
But Dawkins also makes some rather dogmatic philosophical and religious statements without careful discussion. He accepts epistemological reductionism: "The hierarchical reductionist believes that carburetors are explained in terms of smaller units . . . which are explained in terms of smaller units . . . which are ultimately explained in terms of the smallest of fundamental particles. . . . My task is to explain elephants, and the world of complex things, in terms of the simple things that physicists either understand, or are working on." 62
Actually, few pages of the book make any reference to physics, though there are some interesting analogies between DNA and computer programs. Dawkinsís wider claim is stated at the outset: "All appearance to the contrary, the only watchmaker in nature is the blind forces of physics, albeit deployed in a very special way."63 He asserts that natural selection is the only conceivable source of complexity. This leads him in the conclusion to a "disproof" of the existence of God:
The whole book has been dominated by the idea of chance, by the astronomically long odds against the spontaneous arising of order, complexity and apparent design. . . . The same applies to the odds against the spontaneous existence of any fully fashioned perfect and whole beings, including -- I see no way of avoiding the conclusion -- deities.64
Since chance and natural selection are the only source of complexity, Dawkins says, a complex God could not exist. It would have been helpful if he had distinguished more clearly between scientific evidence and philosophical speculation.
Biblical literalism is the second version of Conflict. We have seen some of the overwhelming evidence from diverse disciplines for the occurrence of a long evolutionary history spanning millions of years. The scientific critics of the Modern Synthesis offer absolutely no support to those creationists who say that there is scientific evidence for creation in a few days or a few thousand years. On the other hand, creationists could rightly object if an atheistic philosophy, such as that of Dawkins, were taught in the biology classroom. Both the scientific materialist and the scientific creationist have failed to respect the proper boundaries of science. The former makes statements about religion as if they were part of science. The latter makes statements about science that are dictated by religious beliefs.
2. The Independence of Creation and Evolution.
Neo-orthodoxy has no difficulty accepting the findings of evolutionary biology because science and religion are assigned to separate spheres. God acts in human history, primarily in the person of Christ, and not in the natural world. The argument from design and all forms of natural theology are suspect because they rely on human reason rather than on divine revelation. The doctrine of creation is not a theory about beginnings or about subsequent natural processes; it is an affirmation of dependence on God and the essential goodness and orderliness of the world.
In the previous chapter I indicated my sympathy with many aspects of neo-orthodoxy, particularly its conviction that scripture should be taken seriously but not literally and its characterization of the main theological content of the doctrine of creation ex nihilo. However, its strong emphasis on transcendence leads to a gulf between God and nature and a neglect of divine immanence. Moreover, the absolute dichotomy between humanity and nonhuman nature appears dubious today, along with the body/soul dualism often used to support such a dichotomy. Neo-orthodoxy can express the theological themes of the ex nihilo tradition, once it is divorced from a beginning of time, but it can do little with the continuing creation tradition.
The second version of the Independence thesis is existentialism, which also makes an absolute separation of spheres. God is encountered only in the immediacy of personal involvement, decision, and commitment. God acts only in personal life, not in the impersonal arena of nature. Most existentialists have contrasted the freedom of personal life with the determinism of the laws of nature. Even if determinism is abandoned in recognition of the role of chance, law and chance are equally impersonal. What matters religiously is the transformation of oneís own life in a new understanding of authentic personal existence, which has no connection with theories about mutations and natural selection. The doctrine of creation is an acknowledgment of oneís personal dependence on God and gratitude for oneís life as a gift.
Existentialism offers important insights concerning the character of religious faith. But once again, Godís relation to nonhuman nature gets short shrift. Nature is merely the impersonal setting for the drama of personal existence and individual redemption. The sharp separation of human and nonhuman life does not accord with the evolutionary-view. If the ecological understanding of our participation in the wider web of life is ignored, the door to the exploitation of the environment is left wide open.
The third version of Independence is linguistic analysis. Human life encompasses various self-contained language systems, each with its distinctive rules and functions. Religious language expresses a way of life through the rituals, stories, and practices of a religious community. Creation stories, in particular, provide a cosmic framework of meaning and practical guidance for living. Science, on the other hand, asks strictly delimited questions in the interest of prediction and control. Toulminís early writings suggest that it is an illegitimate mixing of languages when evolution is extrapolated to support either atheism or theism.65
I acknowledge these functions of creation stories in human life, but I do not think that religious beliefs can be ignored. The linguists accept an instrumentalist account of both science and religion; there can be no conflict because neither makes truth claims. As a critical realist, I hold that both fields make statements about reality, though these statements are selective and partial and always revisable. We cannot exclude the possibility that particular statements about creation and about evolution could conflict or support each other. At some points we need to modify traditional religious doctrines in the light of biological evidence. Our goal is a coherent interpretation of all experience, not a collage of unrelated "language games."
3. Dialogue About Creation and Evolution
In the last chapter I suggested that there are no direct inferences in either direction between physical cosmology and the doctrine of creation, but there are some illuminating parallels. I proposed that the contingency of existence and of boundary conditions is consistent with the meaning of ex nihilo, while the contingency of laws and of events is consistent with the idea of continuing creation. Theism does provide grounds for the combination of contingent order and intelligibility that the scientific enterprise presupposes, though these are limit-questions that do not arise in the daily work of the scientist.
Evolutionary biology offers many examples of a fantastically complex order, which evokes our wonder. The intricate structures of DNA and protein molecules are dependent on a myriad of interatomic forces. Molecular structures, in turn, contribute to the higher levels of organization, which lead to the emergence of sentience, purposiveness, consciousness, and self-consciousness. In nature, information-is as important as matter and energy. Perhaps there is some parallel in the theological concept of Word or logos, which can be thought of as a form of information, the communication of meaning and message when correctly interpreted. But if nature is a message from God, it is not easily decoded.
One way of encouraging a second-order dialogue between theologians and scientists, while maintaining the integrity of each enterprise, is to pursue the neo-Thomist distinction between primary and secondary causality. God as primary cause works through the secondary causes, which science describes. There are no gaps in the scientific account, which is complete on its own level. But God sustains the whole natural sequence. Primary causes represent a totally different order of explanation. As McMullin puts it, "He works equally in all parts of His creation." 66 Usually this position assumes the classical doctrines of divine omnipotence and predestination. This would require that God control the indeterminacies that appear to us as chance.
The neo-Thomist position is appealing because it shows great respect for science while maintaining many of the doctrines of classical theism. It tries to avoid deism by asserting that God has a continuing role in sustaining the natural order. It can be supplemented by the belief that occasional acts of miraculous divine intervention occur. But it is difficult to reconcile with the biblical idea that God has a more active continuing role in nature and history. In chapter 9, I will argue that the assumption of predestination encounters problems in dealing with freedom, chance, and evil in the world.
4. The Integration of Creation and Evolution
In trying to relate creation and evolution, can we go further than a dialogue regarding limit questions? In chapter 1, I outlined three kinds of Integration: natural theology; a theology of nature; and systematic synthesis.
1. Natural Theology
Here the claim is that theistic conclusions can be drawn directly from the evolutionary evidence. Unlike the creationists, these authors are well read in contemporary biology and accept a long evolutionary history. However, they sometimes seem to misinterpret the scientific evidence in describing the alleged shortcomings of evolutionary theory. Leconte DuNouy writes, "Chance alone is radically incapable of explaining an irreversible evolutive phenomenon."67 But we have seen that we are not dealing with "chance alone"; we have chance plus stable structures plus natural selection. Charles Raven argues that many coordinated changes would have to have occurred simultaneously for a complex organ like the eye to appear. An eye lens is useless, he says, without a retina, and vice versa.68 But this is a dubious claim; there is in nature a wide diversity of organs of vision, some simple and some complex, some with lenses and some without.
Hugh Montefiore has recently argued that neo-Darwinian explanations of evolutionary change are inadequate and that a theistic explanation is far more probable. He accepts the claims of Raven and others that complex organs and behaviors would require the coordination of many mutations, and thus "some other force seems to be at work here." Chance and natural selection do not explain all these phenomena, so there must be a directive force, and God is "by far the most probable explanation."69 Montefiore is cautious in his claims, but he bases his case on the inadequacies of current scientific explanations, which seems to be a sophisticated form of the "God of the gaps" position. It is vulnerable insofar as these gaps in the scientific account have been or will be filled in.
Such objections from the scientific side cannot be made against the wider teleological argument in which design is built into the laws and processes that science describes. The wider argument does not rely on any particular gaps in the scientific account, and at this point it resembles the scheme of primary and secondary causes. However, teleological arguments have a limited role in theology. There are probably few people whose belief in God was actually reached by such routes. Philosophical reflection without personal involvement or participation in a religious community is far from the actual religious life of humankind. At most, natural theology might have a preliminary or supportive function in theological reflection.
2. A Theology of Nature
Instead of a natural theology, we can have a theology of nature, which is based primarily on religious experience and the life of the religious community, but which includes some reformulation of traditional doctrines in the light of science. Theological doctrines start as human interpretations of individual and communal experience and are therefore subject to revision. Our understanding of Godís relation to nature always reflects our view of nature. In particular, articulation of the continuing creation theme today must take into account the new view of nature as a dynamic, interdependent, evolutionary process of which humanity is a part. Peacockeís writing is a fine example of such doctrinal reformulation, based on thorough familiarity with both evolutionary science and the Christian tradition. He presents continuing creation as a slow and painful travail, an experimental yet purposeful activity, which can be imagined through a variety of analogies and models.
Some interpreters view Teilhard de Chardinís The Phenomenon of Man as a form of natural theology. In the preface he says he will argue from scientific evidence alone (though he grants that consideration of the total human phenomenon goes beyond any of the sciences). But I maintain that the book, seen in the context of Teilhardís writings as a whole, is more appropriately viewed as a theology of nature. His unifying vision is indebted to both evolutionary biology and the Christian tradition, and this vision informs all his writing.70
On the scientific side, Teilhard describes in detail the historical evolution from matter to life, mind, and society. He discusses mutations and chance at several points and speaks of "the billion-fold trial-and-error of mechanical forces."71 He rejects the Lamarckian idea that acquired characteristics can be inherited. But he agrees with Lamarck in assigning a major role to the organismís own efforts and interior life -- the rudimentary forms of sentience and purposiveness which he calls "the within of things." These internal forces are said to use chance variations. Chance is seized and used by a principle of internal self-organization."72 There is slow progress toward greater complexity and consciousness, but not a simple straight-line development. Teilhard does not introduce divine intervention to account for particular gaps in the scientific account. Teleology is displayed in the whole process, not in the design of particular structures.
But the scientific side of the book is subject to several criticisms. He identifies chance with neo-Darwinism and identifies directionality with the operation of "the within." This neglects the extent to which natural selection itself exerts a directional influence. Many scientists object to the way that Teilhard extends scientific terms metaphorically without indicating that he is doing so (radial energy and psychic temperature, for example). He does not distinguish between accepted scientific ideas and more speculative philosophical proposals. In the last two chapters he pictures the "convergence of evolution" and introduces a concept of God as Omega, "the principle we needed to explain the persistent march of things toward greater consciousness." Some scientists dismiss Teilhard as a poet and mystic, but this neglects the seriousness with which he took the scientific data. However, let us grant that he was giving an interpretation of science, not a strictly scientific account.
Teilhardís Christian convictions undoubtedly influenced his portrayal of the directionality of cosmic history and the significance of human personality. These convictions are more explicitly stated in the epilogue of The Phenomenon of Man and are developed in his theological writings. But he does not simply draw on inherited traditional beliefs, for he proposes extensive doctrinal reformulation in the light of the idea of evolution, which he says is "a condition for all thought today." Teilhard defends a divine creativity immanent in the whole natural order. He objects to the separation of sacred and secular realms. Christ is presented not as an intrusion into the world but as the continuation and fulfillment of a long cosmic preparation. According to Teilhard, the purpose of the incarnation was not primarily the "remedial" work of atoning for human sin, but the "constructive" work of uniting all reality and bringing it to union with God. Redemption, then, is social and cosmic as well as individual; creation and redemption form a single process. Sin and evil, which in a static world are difficult to reconcile with the goodness of God, are now seen to be inescapable by-products of a slow creative process.73 Teilhardís theological ideas, in short, are indebted to both evolutionary biology and the Christian tradition. He gives us an evolutionary theology of nature from which we can learn much, despite the problems in his style of writing.
3. Systematic Synthesis
A final version of Integration is the synthesis of evolution and creation within an inclusive metaphysical system. Metaphysics is the search for a coherent set of basic categories applicable to all types of human experience and all events in the world. As such, it must draw from other fields beside science and religion, but it must include the insights of these two areas of human life.
An evolutionary metaphysics will give an important place to temporality and change in its characterization of all entities. It will express the interdependence of all beings in an ecological understanding of the web of life. It will presuppose the continuity of human and nonhuman life, though it can also acknowledge unique characteristics of human existence. It will deal with the distinctive nature of mental life without assuming a mind/body dualism. One way of allowing for both continuity and discontinuity in evolution is the articulation of a metaphysics of levels, in which there are characteristics common to all levels, but novel kinds of organization and activity emerge at higher levels.
Teilhard de Chardinís writing incorporated a partially developed set of evolutionary metaphysical categories. Teilhard rejected much of the Thomistic metaphysics to which he had been exposed in his training as a Jesuit. In place of the Thomistic categories of being and substance, he took becoming and process as the basic characteristics of reality. Instead of identifying perfection with the timeless, he held that time, change, and relatedness are attributes of all beings, including God. Instead of a sharp line between human and nonhuman, or between mind and matter, he held that there is a mental side in all beings. But Teilhardís competence and training were greater in science and in theology than in philosophy. He had greater gifts of poetic imagination and of spiritual intensity than of philosophical reasoning. So we must turn to others for the systematic metaphysical categories in which to express a unified evolutionary and religious vision.
The process philosophy of Whitehead and his followers is the most promising metaphysical system in which evolution and continuing creation can be integrated. We will examine it in chapter 8, after we have carried the evolutionary story a stage further in chapter 7 by considering the evolution of human life.
1. Charles Darwin, letters to Asa Gray (May 22 and Nov. 26, 1860), in Francis Darwin, Life and Letters of Charles Darwin (London: John Murray), 11:312, 378.
2. For example, Gaylord G. Simpson, The Meaning of Evolution (New Haven: Yale University Press, 1949). A good summary of the Modern Synthesis is given in Michael Ruse, Darwinism Defended: A Guide to the Evolution Controversies (Reading, MA: Addison-Wesley, 1982).
3. Hoimar von Ditfurth, The Origins of Life: Evolution as Creation (San Francisco: Harper & Row, 1982).
4. C. H. Waddington, Time Strategy of the Genes (New York: Macmillan, 1957).
5. Alister Hardy, The Living Stream (London: Collins, 1965), chap. 6.
6. R. Goldschmidt, Theoretical Genetics (Berkeley: University of California Press, 1955).
7. S. J. Gould and N. Eldredge, "Punctuated Equilibria," Paleobiology 3 (1977): 115-51.
8. G. Ledyard Stebbins and Francisco Ayala, "The Evolution of Darwinism," Scientific American 253 (July 1985): 72-85; F. Ayala, "The Theory of Evolution: Recent Successes and Challenges," in Evolution and Creation, ed. Ernan McMullin (Notre Dame: University of Notre Dame Press, 1985).
9. Stephen Jay Gould, "Darwinism and the Expansion of Evolutionary Theory," Science 216 (1982): 384.
10. J. L. King and T. L. Jukes, "Non-Darwinian Evolution," Science 164 (1969): 788-98; Motoo Kimura, "The Neutral Theory of Molecular Evolution," Scientific American 241 (Nov. 1979): 98-126.
11. David L. Hull, "A Matter of Individuality," Philosophy of Science 45 (1978): 355-60; Anthony Arnold and Kurt Fristrup, "A Theory of Natural Selection: A Hierarchical Expansion," in Genes, Organisms, Populations: Controversies over the Units of Selection, eds. R. N. Brandon and R. Burian (Cambridge, MA: MIT Press, 1984).
12. John Campbell, "An Organizational Interpretation of Evolution," in Evolution at the Crossroads, eds. David Depew and Bruce Weber (Cambridge, MA: MIT Press, 1985); also "Autonomy in Evolution," in Perspectives on Evolutions, ed. Roger Milkman (Sunderland, MA: Sinauer Associates, 1982).
13. Stuart Kaufman, "Self-Organization, Selective Adaptation, and Its Limits: A New Pattern of Inference in Evolution and Development," in Evolution at the Crossroads, eds. Depew and Weber. See also Marjorie Grene, ed., Dimensions of Darwinism (Cambridge: Cambridge University Press, 1984).
14. Mae-Wah Hoh and P. T. Saunders, eds., Beyond Neo-Darwinism: An Introduction to the New Evolutionary Paradigm (New York: Harcourt, Brace, Jovanovich, 1984).
15. S. Miller and L. Orgel, The Origins of Life on the Earth (Englewood Cliffs, NJ: Prentice-Hall, 1974); C. Folsome, The Origin of Life (San Francisco: W. H. Freeman, 1979).
16. A. G. Cairns-Smith, Seven Clues to the Origin of Life (Cambridge: Cambridge University Press, 1985), and "The First Organisms," Scientific American 252 (June 1985): 90.
17. Manfred Eigen et al., "The Origin of Genetic Material," Scientific American 244 (April 1981): 88-118.
18. Jeffrey Wicken, Evolution, Thermodynamics, and Information (New York and Oxford: Oxford University Press, 1987).
19. Jeremy Campbell, Grammatical Man: Information, Entropy, Language, and Life (London: Penguin Books, 1982), p. 265.
20. David Wilcox, "Of Messages and Molecules" (Paper presented at Princeton Center for Theological Inquiry, Oct. 23, 1988).
21. Wicken, Evolution, p. 177.
22. Herbert Simon, "The Organization of Complex Systems," in Hierarchy Theory, ed. Howard Patee (New York: George Braziller, 1973).
23. Niles Eldredge and Stanley Salthe, "Hierarchy and Evolution," in Oxford. Surveys of Evolutionary Biology 1984, ed. Richard Dawkins (Oxford: Oxford University Press, 1985); Stanley Salthe, Evolving Hierarchical Systems (New York: Columbia University Press, 1985); F. H. Allen and Thomas B. Starr, Hierarchy: Perspectives on Biological Complexity (Chicago: University of Chicago Press, 1982). See also Marjorie Grene, "Hierarchies in Biology," American Scientist 75 (1987): 504-10.
24. Francis Crick, Of Molecules and Men (Seattle: University of Washington Press, 1966), pp. 14 and 98.
25. See Barbour, Issues in Science and Religion, pp. 327-37; Francisco Ayala, "Introduction," in The Problem of Reduction, eds. F. Ayala and T. Dobzhansky (Berkeley and Los Angeles: University of California Press, 1974);íArthur Peacocke, God and the New Biology (London: J. M. Dent and Sons, 1986), chaps. 1 and 2.
26. Clifford Grobstein, "Levels and Ontogeny," American Scientist 50 (1962): 52.
27. Ernst Mayr, The Growth of. Biological Thought (Cambridge: Harvard University Press, 1982), chap. 2.
28. Alexander Rosenberg, The Structure of Biological Science (Cambridge: Cambridge University Press, 1985), chaps. 2, 4, and 8.
29. Ernest Nagel, The Structure of Science (New York: Harcourt Brace, 1961), chap. 11.
30. Morton Beckner, The Biological Way of Thought (New York: Columbia University Press, 1959), chap. 6; also "Reduction, Hierarchies and Organicism," in The Problem of Reduction, eds. Ayala and Dobzhansky.
31. Francisco Ayala, "Reduction in Biology: A Recent Challenge," and Ernst Mayr, "How Biology Differs from the Physical Sciences," in Evolution at the Crossroads, eds. Depew and Weber.
32. Lindley Darden and Nancy Maull, "Interfield Theories," Philosophy of Science 44 (1977): 60 and 61.
33. William Wimsatt, "Reductionism, Levels of Organization, and the Mind-Body Problem," in Consciousness and the Brain, eds. G. Globus, G. Maxwell, and I. Savodnik (New York: Plenum, 1976); also "Reduction and Reductionism," in Current Issues in Philosophy of Science, eds. P. D. Asquith and H. Kyberg (New York: Philosophy of Science Association, 1978).
34. Stephen Toulmin, "Concepts of Function and Mechanism in Medicine and Medical Science," in Evaluation and Explanation in the Biomedical Sciences, eds. H. T. Engelhardt and S. Spicker (Boston: D. Reidel, 1975), p. 53.
35. Charles Hartshorne, Reality as Social Process (Glencoe, IL: Free Press, 1953), chap. 1; The Logic of Perfection (LaSalle, IL: Open Court, 1962), chap. 7.
36. Michael Polanyi, "Lifeís Irreducible Structures," Science 160 (1968): 1308-12.
37. Donald Campbell, "ĎDownward Causationí in Hierarchically Organized Biological Systems," in The Problem of Reduction, eds. Ayala and Dobzhansky.
38. Holmes Rolston, Science amid Religion: A Critical Survey (New York: Random House, 1987), pp. 286-89.
39. Barbour, Issues in Science amid Religion, pp. 337-44.
40. Stephen Walker, Animal Thought (London: Routledge & Kegan Paul, 1983); Donald R. Griffin, Animal Thinking (Cambridge: Harvard University Press, 1984).
41. W. E. Agar, A Contribution to the Theory of the Living Organism, 2d ed. (Melbourne, Australia: Melbourne University Press, 1951); Bernhard Rensch, "Arguments for Panpsychistic Identism," in Mind in Nature, eds. J. B. Cobb, Jr. and D. Griffin (Washington, DC: University Press of America, 1977).
42. Sewall Wright, "Gene and Organism," American Naturalist 87 (1953): 14; also "Panpsychism and Science," in Mind and Nature, eds. Cobb and Griffin.
43. Stephen Jay Gould, The Pandaís Thumb (New York: Penguin Books, 1980), chap. 1.
44. Jacques Monod, Chance and Necessity (New York: Vintage Books, 1972).
45. Fred Hoyle and Chandra Wickramasinghe, Evolution from Space (London: Dent, 1981).
46. John Maynard-Smith, On Evolution (Edinburgh: University of Edinburgh Press, 1972), p. 89.
47. Stephen Jay Gould, Ever Since Darwin (New York: W. W. Norton, 1977), p. 45.
48. John Bowker, "Did God Create This Universe?" in The Sciences amid Theology in the Twentieth Century, ed. Arthur Peacocke (Notre Dame: University of Notre Dame Press, 1981).
49. Robert John Russell, "Entropy and Evil," Zygon 19 (1984): 449-68.
50. D. J. Bartholomew, God amid Chance (London: SCM Press, 1984).
51. William Pollard, Chance amid Providence (New York: Charles Scribners Sons, 1958), chap. 3.
52. Donald MacKay, Science, Chance, and Providence (Oxford: Oxford University Press, 1978); Peter T. Geach, Providence and Evil (Cambridge: Cambridge University Press, 1977). See also Barrie Britten, "Evolution by Blind Chance," Scottish Journal of Theology 39 (1986): 341-60.
53. L. J. Henderson, The Fitness of the Environment. (New York: Macmillan, 1913).
54. F. R. Tennant, Philosophical Theology, vol. 2 (Cambridge: Cambridge University Press, 1930).
55. John Polkinghorne, One World: The Interaction of Science and Theology (Princeton: Princeton University Press, 1987), p. 69.
56. L. Charles Birch, "Creation and Creator," Journal of Religion 37 (1957): 85, and Nature and God (London: SCM Press, 1965).
57. Conrad Hyers, The Meaning of Creation (Atlanta: John Knox, 1984), chap. 8.
58. Peacocke, Creation amid the World of Science, pp. 131-38; Intimations of Reality, p. 76.
59. Peacocke, Creation, pp. 142-43; Intimations, p. 64.
60. Peacocke, Creation, p. 95.
61. Peacocke, Intimations, p. 66.
62. Richard Dawkins, The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe without Design (New York: W. W. Norton, 1987), pp. 13 and 15.
63. Ibid., p. 5.
64. Ibid., p. 317.
65: Stephen Toulmin, "Metaphysical Beliefs," in Metaphysical Beliefs, ed. A. Macintyre (London: SCM Press, 1957).
66. Ernan McMullin, "Natural Science and Belief in a Creator," 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).
67. Leconte DuNouy, Human Destiny (New York: Longmanís, Green, 1947), p. 82.
68. Charles E. Raven, Natural Religion amid Christian Theology (Cambridge: Cambridge University Press, 1953), 2:183.
69. Hugh Montefiore, The Probability of God (London: SCM Press, 1985), chap. 10.
70. Ian G. Barbour, "Five Ways of Reading Teilhard," Soundings 51 (1968): 115-45.
71. Pierre Teilhard de Chardin, The Phenomenon of Man (New York: Harper & Row, 1959), p. 302.
72. Teilhard, Manís Place in Nature (New York: Harper & Brothers, 1966), p. 108.
73. Teilhard, Christianity and Evolution (New York: Harcourt Brace Jovanovich, 1971).