In the previous chapter, we began our explanation of design arguments with the example of a walker who finds a spherically shaped rock and then later finds a rock seemingly shaped for a particular use or function. In both cases, the walker was tempted to reason from pattern or structure to the existence of an intelligent agent of patterning or structuring. We suggested that these two cases were both rudimentary examples of the kind of reasoning that goes on in arguments that appeal to design.
Of course, there is also at least one major difference in the two cases. The first case, based on the spherically shaped rock, appeals to the regularities or symmetries inherent in nature. These regularities or symmetries are the sorts of patterns one generally encounters in studying modern physics. The second case, which is based on the possible utility of the rock, appeals to function. Such functions are the sorts of structures one generally encounters in biology. This distinction is at best only a rule of thumb, for one can easily think of counterexamples to it. For example, the structures of living things sometimes also exhibit symmetries.
The distinction is useful, however, for beginning to grasp how design arguments try to make their case. In the previous chapter, we gave a rather simple overview of the sorts of “spherically shaped rocks” the contemporary physicist encounters while doing his work. We discussed the sorts of symmetries expressed in laws and the structures of atoms that, perhaps, constitute evidence of design. Now we will turn to the sort of “functional rocks” the student of biology encounters in doing his work. We will be discussing the sorts of structures evident in living organisms and ask about how to account for such structures.
The parallelism between design-type arguments in contemporary physics and those in contemporary biology is such that there is likewise a parallelism inherent in the responses that critics make against such arguments. That is, the principal response of the critics of design arguments in physics is to explain symmetrical structures through randomness and to posit randomness, ultimately, in terms of the theory of the multiverse; as we shall see, the principal response of the critics of design arguments in biology is to explain structure through randomness and to posit randomness in terms of the theory of natural selection working upon random genetic variation.
The parallelism between the two is not perfect, however. For example, the multiverse theory is still extremely speculative; hard evidence is not plentiful, at least not yet. Intelligent people on all sides of the debate seem to be aware that their claims and counterclaims are tentative and provisional, and almost everyone admits that the arguments about multiverses are still in their infancy. The debates about natural selection, Darwinism, and what has come to be termed, sometimes imprecisely, as “evolution” have been with us now for a relatively longer time; evidence is far more readily available. Still, the matter has become controversial, and the camps are dug in.
As will become clear, it is our view that the continuing controversies about “evolution” produce more heat than light; most of all they give rise to confusion, misunderstandings, and often ill will. Thus, before we can even get to the heart of this explosive matter as it pertains to questions of reason and faith, it is necessary to make some basic distinctions.
A. Two Common Meanings of “Evolution”
Let us begin with an analogy. Let us say that we were writing about the Battle of Fort Sumter on April 12, 1861, rather than about evolution. There would be at least two ways to approach the problem. We might write simply about “what happened”. If that were our task, we would write about the position of certain troops and sailors in relation to the fort just prior to the beginning of the battle. We might also describe the fort itself and then write about the chronological sequence of movements involved in the attack on the fort. We might even chronicle the noise of bombs and rifles and men shouting and screaming. We would talk about men shooting and dying.
Another way to write about the Battle of Fort Sumter would be, not in terms simply of describing “what happened”, but in terms of “why” it happened. What explains the battle? If this were our task, we would have to write about things like the invention of the cotton gin, the Dred Scott decision, the Kansas-Nebraska Act, the presidential election of 1860, and a great many matters in addition.
The two tasks are not completely unrelated, of course, but our point is that the question “What happened?” is different from the question “Why did it happen?” Just as such questions can be differentiated in history, so can they be differentiated in physics. The statement “This apple fell to the ground” is simply “what happened”. The statement “Gravity, as explained by Newton, caused the apple to be gravitationally attracted to the earth, and vice versa”, attempts to explain “why” the apple fell to the ground. The first statement describes a change; the second attempts to explain the change.
A similar distinction is necessary for understanding what is meant by the term “evolution”. In one sense, evolution simply means “what happened”. And according to the theory of evolution in this sense, what happened is that a single life form able to replicate itself changed into another life form, and that life form changed into another or branched into two or three or a great many life forms, and those changed and branched into still more and more life forms, until we eventually got to the current situation in which there is a great diversity of developed life forms. “Evolution” in this sense is the name given to a change or a great many changes. “Evolution” in this sense—the sense of “the theory of the common ancestry of all living things”—names “what happened”. “Evolution” in this sense describes a series of changes.
Just as we can also ask about “why” the Battle of Fort Sumter occurred, however, so we can ask about “why” the great change in living organisms has occurred. “Evolution” or “the theory of evolution” in this second sense seeks to explain “evolution” in the first sense. Evolution in the second sense, as most of us learned in high school biology class, talks about principles of change such as random genetic mutations and natural selection.
Our point is simply that “what happened” is not the same as “why it happened”; nor is “a description of change” the same as “an explanation of change”. If we keep this distinction in mind, it will be possible to avoid a great deal of confusion in talking about evolution, for “evolution” is a word with at least two quite distinct meanings. Trained biologists are usually careful to keep the two meanings separate, and indeed they normally refer to “evolution” in the second sense as “natural selection”. In fact, Darwin’s famous book included “natural selection” in its very title: On the Origin of Species by Means of Natural Selection. Nonspecialists, though, often tend to run the two meanings together, and since this book is written with nonspecialists in mind, we need to be careful to consider each of the two concepts separately and in turn.
B. The “What Happened?” Question and Theistic Responses
Why does contemporary biology think that the description of the change summed up in the assertion of the common ancestry of all living species is true? By now, we hope the answer to this question is clear: it is because of the study of morphological structures that biology thinks the narrative described by the phrase “common ancestry” is true. To use a very simple example, one notices that a lynx and a mountain lion have certain features in common. One wonders whether one might have come from the other or whether both might have come from some common ancestral cat. One does not have to be Charles Darwin to begin to think about evolutionary biology!
Of course, mere similarity of morphological features does not seem to prove common ancestry. Contemporary biology can point to plenty of other evidence, though, in order to bolster the narrative it gives about the great changes that have taken place in living forms on the earth. Fossils, for example, are well-known sources of such evidence. Sometimes fossils provide evidence of an animal clearly distinct from contemporary animals and yet whose functional structures are quite similar in particular ways. Such an animal is therefore plausibly thought to be an ancestor of the currently existing species. Another, more recent source of supporting evidence for the narrative of common ancestry is the study of DNA, which has shown that there are certain sequences of DNA structure that are repeated in distinct species. This sequenced DNA structure, if sufficiently specific, suggests that the distinct species are related. If species A has a relatively specific DNA sequence that is repeated in species B, it is not hard to conclude that probably A is the ancestor of B or, more probably, that both have a common ancestry.
Isolated, single instances of shared functional structures perhaps do not provide much evidence, but contemporary biology has identified thousands upon thousands of such structures and, on the basis of such evidence, has been able to assemble a narrative about “what happened”—that is, a narrative about the evolutionary history of the earth’s living species. The totality of the structural evidence supporting this narrative has by now become so extensive that human reason, operating inductively, concludes that it is extremely likely that all living things arose from an initial organism. In other words, human reason concludes that the narrative about common ancestry is extremely likely to be true.
Let us imagine that we were standing on the beach at Fort Sumter in 1861 with a video camera in hand. We would be able to record “what happened”. Later, we could view the video and see once again what changes occurred in space and time on that day. Now let us imagine that we were present when the first life form emerged upon the earth (or within its oceans), and let us also imagine that we have lived upon the earth from that time to this, and, finally, let us imagine that we have a sort of “time-lapse” video camera that has been recording changes in life forms from the beginning to contemporary times. Presumably we could now view the video and see, visually, the changes in life forms as they emerged from antecedent species.
Such a reconstructed video of the basic contours of the evolutionary change can be derived through the study of morphological structures. (And actually, biologists tell us that we do already have a sort of “video” that plays itself out within the womb, for the development of an embryo “recapitulates” major evolutionary changes within the life of its species.) Notice, though, that the “movie” we would have recorded on the beach at Fort Sumter would not have told us why these soldiers had assembled on the beach or why the fort was being attacked by some and defended by others, and neither would our movie of the biological history of the earth tell us why one form changed into another or why two species emerged from one.
What do theists have to say about this “movie” constructed by evolutionary biology? If considering the matter on the basis of rational argumentation alone, theists would not necessarily have anything to add or to subtract from the movie. Intelligent theists and nontheists alike might argue that a scene here or there in the movie seems implausible and perhaps needs to be rewritten somewhat; contemporary biologists are themselves constantly doing this. A fossil find here or there around the world means that an episode in the movie should be altered somewhat. But theists, as theists, do not have any particular or unique criticism to make about the movie.
To be sure, theists, basing themselves on reason alone, would probably want to ask whether, given all these incredible and amazing similarities and parallels in the development of functional structures in living things, we ought not to conclude that an agent very wise and powerful must have established the natural processes that could give rise to such structures. To take the argument in that direction, though, moves us into the realm of explaining change rather than merely describing or recording it, so we will save such a question for the next part of the chapter.
Some theists, however, basing themselves upon an appeal to the revelation found at the beginning of the Book of Genesis, have claimed that the “movie” of evolutionary change assembled by contemporary studies in biology conflicts with the “movie” offered in the Bible. To be sure, if one reads the Genesis account as a movie depicting change, it does indeed conflict with the movie produced by reason working within modern biology. And indeed, over the centuries, there have been many religious theists who have thought that faith and reason simply conflicted in this matter and who therefore veered off into fideism by rejecting biological studies or who veered off into rationalism by rejecting the revelatory nature of the Bible.
It has also been the case, however, that among the more sophisticated theistic exegetes of the Bible there have always been those who understood the Genesis account as being more than a movie. It was also a symbolic or representative account, they thought, of the principles of order in creation rather than a mere chronology of what happened during a period of six twenty-four-hour days.
Perhaps another analogy would help explain this point. Let us try to remember a time during our childhood when our mother or father read to us a book that began with the words “Once upon a time. . .” We knew immediately that a story that begins in this manner might well include talking animals, princes or princesses, fairies, unicorns, and a host of other nonexistent phantoms. We also learned that such stories might well be “true” in the sense that their point or “moral” was true, but we also knew that they were not strictly or historically or—we often say somewhat imprecisely today—“literally” true. Similarly, if we read Agatha Christie novels, we anticipate that we will encounter a character named Hercule Poirot and that this detective will prove to be extremely wise and insightful. He knows a lot of truth. But at the same time we know that Hercule Poirot is not a real person.
On the other hand, if we purchase a book on the history of the Civil War at a bookstore, we expect that what the book says will be chronologically accurate, say, about Robert E. Lee. We expect that the book will be accurate with respect to when and where the Army of Northern Virginia engaged the Union army and that, indeed, it knows what it is talking about when it says that the Battle of Gettysburg began on July i. It will give us the “literal” truth about “what happened”. The book may or may not also attempt to answer the question of “why” events in the Civil War happened, but if it does try to answer the “why” question, we will expect that it will at least give us accurate evidence as to why its explanations are probably true.
We might say, then, that fairy tales, murder mysteries, and histories of the Civil War are all different forms of writing, or different genres. All of them contain or may contain truth; all of them make claims about how things really are or were. But because their genres differ, we have to be attentive to which genre we are reading in order to know how to find the truth in each. The problem we encounter upon reading the Book of Genesis is that we are not necessarily familiar with the genre in which the writing occurs. The cycle of stories about Abraham seems to be different from the stories about the man and the woman in the garden, and both seem to be different still from the story about the seven days. The story about the seven days, moreover, seems to be in a genre far different from that of Paul’s Letter to the Galatians or the beginning of the Book of the Acts of the Apostles. Most students of the Bible in our time, and some students of the Bible in times past, have concluded that the genre in which the story of the seven days is written is not a genre like that of a Civil War history book. The events of the seven days, indeed, seem to say something about God and creation, but they are not written down in the genre in which, say, the earlier chapters of the book you are holding in your hands speaks about God and creation. This is not to say that the story of the seven days does not contain truth, but the truth of that story has to be understood within the context or the “rules” of the genre in which it is written.
Among Christian theists in our time, it is sometimes the case that less experienced readers of the Scriptures overlook the genre in which the story of the seven days is written. This is understandable, inasmuch as there are not a lot of examples of the seven-days narrative to train us, whereas there are a lot of examples of murder mysteries or fairy tales or Civil War histories. Nevertheless, in our view this misreading has led to a lot of confusion among some theists, who sometimes think they are abandoning their faith unless they interpret the story of the seven days as belonging to a genre of writing to which it does not belong.
Since many of our readers may be Roman Catholics, we will add that this tendency of reading the story of the seven days as a chronological history, while not unknown, is less prevalent among Catholics than among some other Christian groups. With respect to Darwinism in particular, the Catholic Church did not really even think it necessary to have an articulated position for many years. Finally, in order to be quite clear on the matter, in an encyclical letter of 1950 titled Humani generis, Pope Pius XII stated that Catholics were free to believe that the human body evolved from the bodies of earlier animals. If one reads the letter, one has the sense that the papal author is skeptical of the theory of the common ancestry of all living things, but he does not see that the theory of common ancestry contradicts Christian faith. The encyclical is concerned about the implications that some people draw from the theory of common ancestry, but we will take up that part of the question in the next chapter.
C. Theistic Responses to the “Why Did It Happen?” Question
Contemporary biology does not simply develop a narrative about “what happened” in the biological history of the earth, however. It does not just describe a change. It also attempts to explain that change or vast series of changes. Darwin’s Origin of Species attempts to do both tasks; it describes a narrative of change and also tries to explain it. Darwin was hardly the first person to describe a process of narrative change; his fame rests instead on the principles he offered for explaining that change. The most prominent of the explanatory strategies Darwin employed was “natural selection”, or the idea that species mutate into different genetic or morphological forms and hence cause the survival and propagation of certain members of the species but not of other members, which, if reproductive isolation eventually occurs, could result in the emergence of new species.
A contemporary biologist reading The Origin of Species might think that Darwin, while surely on the right track and indeed remarkably accurate, was not entirely successful in giving a complete explanation of evolutionary change. In particular, Darwin did not have in his intellectual possession a solid account of genetics; he thus lacked a mechanism needed to make his theory readily acceptable to all. Although he was a contemporary of Gregor Mendel (an Augustinian friar), Mendel’s pioneering work in genetics was almost completely ignored by scholars until the early twentieth century. Only then was Mendelian genetics used to explain how the variations in species depicted by Darwin could be transferred to subsequent generations. The recovery of Mendel’s ideas enabled Darwin’s theory of natural selection to become the generally accepted explanation of speciation in biology. In other words, the merging of modern genetics and Darwin’s earlier work gave rise to what is often called “neo-Darwinism”, and the neo-Darwinian explanation of evolutionary change, although refined along the way, is still the basic principle of explanation used to account for the biological history of the earth.
The theory of natural selection as the cause of evolutionary change, if simplified dramatically, goes something like this: First, we find among the members of a particular life form or species a certain range or variation of qualities and properties; some of the chipmunks, for example, are just a little different from the others. Second, usually there is a struggle for survival among the members of a species, and the members who are more likely to survive are those possessing certain variations; the giraffe with the longest neck, for example, is more likely to survive because it is better able to reach the leaves on the trees for food or because it is able to swing its heavy head more effectively during fights between males. Third, the surviving members are the ones who reproduce and pass on to their offspring through their genes the traits that enabled them to compete successfully. Stated even more briefly, the principles would seem to be (a) variation; (b) survival of the best adapted; (c) successful reproduction, and hence genetic fitness.
Now, what should a theist think about natural selection? Sometimes theists have been skeptical about the theory of natural selection, but not for reasons that have anything to do with theism. Thus, both theists and nontheists have pointed out that there seem to be aspects of biological change that the theory of natural selection does not explain very well. For example, it has been argued that the theory does not seem to be able to explain very well how life first arose. It assumes that there was something antecedent from which something subsequent was selected; but how can we account for the first life form? If it arose through a natural process, why does that process not repeat itself all the time? The answer is usually thought to have to do with changing conditions on the earth. Presumably the earth was far warmer at an earlier point, and thus biologists are very interested in the simple life forms that survive in “heat vents” in the ocean floor or in geysers in places like Yellowstone Park. But so far, at least, no completely satisfying explanation of the origin of life seems to have emerged from this research. Of course, it is not clear that this objection would really tell against the theory of natural selection itself, for Darwin’s point was about the emergence of different species from a first one or from a first cell; he was not making claims about the emergence of the first cell from nonliving elements. Still, it might seem to some that Darwin’s theory assumes some sort of starting point that no one has been able to explain well—so far, at least.
Another criticism that has been made of the theory of natural selection is that it perhaps does not explain very well the frequent changes in the rate of species development in biological history. That is, if the theory of natural selection were true, one might anticipate, the criticism says, that the development of species upon the earth would be consistently gradual. Perhaps we should expect, the criticism says, that there would be a lot of transitional forms in the fossil record, but in fact what one finds there is rather rapid movement from one stable species to another stable species. The Cambrian period in the earth’s history witnessed, it is thought, a dramatic “explosion” in the rate of evolutionary change, whereas the theory of natural selection would seem, perhaps, to predict a rather stable rate of biological change.
Rational people, therefore, have thought that there are possibly problems here or there within the theory of natural selection; however, these critics may be theists or not. In other words, while they may criticize the theory, they are not necessarily doing so because it is contrary to theism. Such critics of the theory, moreover, generally accept the theory on the whole; they just think that further developments and refinements are necessary before the theory can provide the complete explanation to which it aspires. And, of course, biologists are themselves constantly attempting to provide those refinements to the theory. For example, the notion of “punctuated” evolutionary change has been developed to attempt to explain the changes of the rate of biological change that were mentioned above. The development of punctuated evolutionary accounts is deemed very successful by most biologists working today.
One point about which the theory of natural selection and theism are thought by some really to be in tension concerns the possible role played by randomness within natural selection. We indicated above that the theory of natural selection could be (greatly) simplified into three basic “steps”: variation within species, survival of the fittest of the variants, and genetic transferal through reproduction. A theist looking at this natural process called “natural selection” might be inclined to see in it the makings of a design argument. After all, the sorts of organic structures biologists uncover in their studies of living organisms are much more complex than the sorts of structures physicists uncover, and we noted in the previous chapter that at least some reasonable theists think that a respectable design argument can be based on those physical structures. Why not investigate, then, whether natural selection might be an indication of design? Since it is a natural process that gives rise to extremely complex structures, why not think, a theist might ask, that natural selection is even an instrument of divine providence?
William Provine, a historian of biology, has pointed out that prior to the merging of Mendelian genetics with Darwin’s theory of natural selection, many scholars did interpret natural selection as “God’s way” of providing for the development of life in the world. More recently, though, neo-Darwinians have sometimes claimed that the first “step” in the process of natural selection, the step involving variations within species, is the result of purely random genetic mutations that cannot be linked to anything larger than themselves. According to this view, the process of natural selection has no purposive function. It creates structure but does not have structure in view. Complex biological structures that suffice to meet complex biological needs are merely accidents produced randomly. Since the first “step” in the process is based on randomness, their argument claims, the process as a whole is not purposive or designed.
The claim that the natural selection process begins with randomness is the majority view among professional biologists at present, but explanations that appeal to randomness are always suspect, at least if they base themselves on randomness alone. To say that they are “suspect” is not to say that they are false, of course, but only to say that they have a hard time establishing themselves rationally. And so it is not surprising that criticisms of the view that natural selection is random have been forthcoming from both theists and even nontheists.
It would be our view that the matter requires further investigation, and in fact such investigation is proceeding. It is not uncommon for what seems to us to be randomness to play a role in natural processes, so it would not be surprising if there are always aspects of the natural process of natural selection that seem purely random to human beings. Still, usually natural processes contain many elements or aspects that are not purely random, so it would seem possible that natural selection will eventually come to be viewed as something more than a purely random process too.
In the meantime, we have to limit ourselves to thinking hypothetically about this issue. Let us say that the view insisting upon randomness alone turns out to be the correct one; what follows? Some atheists think that this randomness means that natural selection gives us structure without design and that therefore nature as a whole is without purpose and that therefore God does not exist, and, therefore, human life has no ultimate meaning. Provine himself reaches such a conclusion. Of course, none of these conclusions follows necessarily. From the fact that there is some randomness within nature—at least from the human side of things—it does not follow that there is no design in nature. Indeed, even if it should turn out that randomness is a primary factor in the emergence of species, one still has to account for all the apparent indications of design that we discussed with respect to physics in the previous chapter. All the evidence would have to be taken into account, not simply one piece, even if that piece is a significant one.
And what follows if it should turn out that natural selection is not based solely on randomness? Well, it seems that that could turn out to be one more piece of evidence in favor of the design argument—one would have to consider the evidence itself to know. Coupled with other pieces of evidence, evolutionary theory would possibly strengthen design claims by theists. Theistic arguments appealing to design are ultimately inductive arguments, not deductive proofs, as we have already said. Their relative strength or weakness is advanced or reduced by each piece of evidence. It is not clear whether natural selection will advance or restrict the design argument in the end, but if it turns out to be like other natural processes studied by contemporary natural science, it may turn out to do the former.
D. Conclusion: The One Real Point of Conflict
The last three chapters have attempted to sift through the implications of the study of living and nonliving nature for the question of the relationship of reason and faith. In chapter 16, we suggested that the rise of Big Bang cosmology actually supports theism more than its predecessor, the Newtonian theory of gravity, does. In chapter 17, we suggested that the study of the structures of our physical universe may provide increased evidence for a theistic interpretation of nature along the lines of a design argument. And in this chapter, we have suggested that the study of biological structures leaves us with questions still to be determined. On the whole, then, the claims about a “war” between modern natural science and theistic faith appear to be great exaggerations, and, indeed, the movement is toward the coherence and even, to some extent, the integration of the two.
With respect to some interpretations of neo-Darwinism, however, there is an argument that has emerged about human nature that really does put faith and reason on a potential collision course. Some people think that one of the implications of Darwin’s thoughts on evolution is that human beings are neither free nor intelligent beings—a conclusion that would surely conflict with the description of humanity offered in the Sacred Scriptures, not to mention our direct experience. It is to this conflict that the following chapter will turn.