Dialogue
Plantinga's Defense of Special Creation
University of Notre Dame
Notre Dame IN 46556
Christian Scholars Review XXI:1 (September 1991):
55-79.
Used by Permission
My colleague, Alvin Plantinga, bids the reader of his essay, "When faith and reason clash: Evolution and the Bible," to take his spirited defense of special creation "with a grain of salt." Perhaps he will forgive me if I take it seriously, because I think that this is how many readers would take it, in the context of the continuing controversies about "creation science."
1. Theistic science
His thesis in regard to evolution is that, for the Christian, the claim that God created mankind, as well as many kinds of plants and animals, separately and specially, is more probable than the claim of common ancestry that is central to the theory of evolution. And his larger context is that of an exhortation to Christian intellectuals to join battle against "the forces of unbelief," particularly in academia, instead of always yielding to "the word of the experts." These intellectuals must be brought to "discern the religious and ideological connections... [they must not] automatically take the word of the experts, because their word might be dead wrong from a Christian standpoint." The implication that worries me is that Christian intellectuals should ally themselves with the critics of evolution, despite the almost universal support it has among experts in the relevant fields of natural science.
The "science" these Christian intellectuals profess will not be of the usual naturalist sort. Their account of the origin of species, for instance, will be at odds with that given by Darwin, on grounds that are distinctively Christian in content. Despite the fact that claims such as these on the part of the Christian depend on what he or she knows "by faith, by way of revelation," Plantinga believes that they can appropriately be called science, and he suggests as labels for them "theistic science" or "Christian science." An important function of this broader knowledge would be revisionary. He reminds us that "Scripture can correct current science," in regard to whether or not, for example, the universe originated at a particular moment in the past.
Plantinga's "theistic science" bears some similarity to the "creation science" that has commanded the headlines in the U.S. so often in recent decades. Like creation scientists, he maintains that the best explanation of the origin of "many kinds of plants and animals" is an interruption in the ordinary course of natural process, a moment when God treats "what he has created in a way different from the way in which he ordinarily treats it." Like them, he relies on a critique of the theory of evolution, pointing to what he regards as fundamental shortcomings in the Darwinian project of explaining new species by means of natural selection, and emphasizing recent criticisms of one or other facet of the synthetic theory from within the scientific community itself. Like them, he calls for a struggle against prevailing scientific orthodoxy, one which may pit the teachers of Christian youth against the "experts."
But the differences between them are obvious.1 Most creation-scientists believe in a "young earth" dating back only a few thousand years, and attempt to undermine the many arguments that can be brought against this view. Plantinga allows "the evidence for an old earth to be strong and the warrant for the view that the Lord teaches that the earth is young to be relatively weak." The creation scientists argue for a whole series of related cosmological theses (that stars and galaxies do not change, that the history of the earth is dominated by the occurrence of catastrophe, and so forth); Plantinga focuses on the single issue of the origins of the kinds of living things, and especially of humankind. And he is in the end more concerned to combat the claims of certainty made by the evolutionists than he is to argue that the Christian is irrevocably committed against a full evolutionary account of origins. He allows (which the creation-scientists, I suspect, would not) that as evolutionary science advances, his own present estimate that special creation is more likely might have to give way.
The creation-scientists attempt to detach their arguments from any sort of reliance on Scripture, or more generally, from theological considerations, whereas Plantinga appeals explicitly to the Scriptural understanding of the manner of God's action in the world. The former make a heroic attempt to qualify their creationism as "scientific," in what they take to be the conventional sense of that term. Their effort, I think it is fair to say, was hopeless right from the start. But it may have been prompted as much by political necessity as by strength of conviction regarding the purely scientific merits of their arguments. The creationists would undoubtedly have preferred to defend a view more explicitly based on the Bible, but the exigencies of the constitutional restrictions on what may be taught in Plantinga's Defense of Special Creation the public schools of the U.S. prevented this. The scientists among them would have wanted to shore up their case with various consonances between the catastrophism of their young-earth account and the geological record. But the inspiration for their account lay, and clearly had to lie, in the Bible. Trying to fudge this, though understandable in the circumstances, proved a disastrous strategy.
Plantinga offers a far more consistent theme. True, his "theistic science" will not pass constitutional muster, so it will not serve the purposes for which creation-science was originally advanced. But that not an argument against it; it is merely a consequence of the unique situation of public education in the U.S., a situation that imposes losses as well as gains. I do not think, however, that "theistic science" should be described as science. It lacks the universality of science, as that term has been understood in the Western tradition. It also lacks the sort of warrant that has gradually come to characterize natural science, one that points to systematic observation, generalization, and the testing of explanatory hypothesis. It appeals to a specifically Christian belief, one that lays no claim to assent from a Hindu or an agnostic. It requires faith, and faith (we are told) is a gift, a grace, from God. To use the term "science" in this context seems dangerously misleading; it encourages expectations that cannot be fulfilled, in the interests of adopting a label generally regarded as honorific.
Plantinga objects to the sort of "methodological naturalism" that would deny the label "science" to any explanation of natural process that invokes the special action of God; indeed, he characterizes it, in Basil Willey's phrase, as "provisional atheism." "Is there really any compelling or even decent reason for thus restricting our study of nature?" he asks. But, of course, methodological naturalism does not restrict our study of nature; it just lays down which sort of study qualifies as scientific. If someone wants to pursue another approach to nature-and there are many others-the methodological naturalist has no reason to object. Scientists have to proceed in this way; the methodology of natural science gives no purchase on the claim that a particular event or type of event to be explained by invoking God's creative action directly. Calling this methodological naturalism is simply a way of drawing attention to the fact that it is a way of characterizing a particular methodology, no more. In particular, it is not an ontological claim about what sort of agency is or is not possible. Dubbing it "provisional atheism" seems to me objectionable; the scientist who does not include God's direct action among the alternatives he or she should test scientifically when attempting to explain some phenomenon is surely not to be accused of atheism!
Let me make myself clear. I do not object (as the concluding section of this essay will make clear) to the use of theological considerations in the service of a larger and more comprehensive world-view in which natural science is only one factor. I would be willing to use the term "knowledge" in an extended sense here (though I am well aware of some old and intricate issues about how faith and knowledge are to be related).2 But I would not be willing to use the term"science," in this context. Nor do I think it necessary to do so in order to convey the respectability of the claim being made: that theology may appropriately modulate other parts of a person's belief-system, including those deriving from science. I would be much more restrictive than Plantinga is, however, in allowing for the situation he describes as "Scripture correcting current science," But before we come to our differences, it may be worth laying out first the large areas where he and I agree.
2. Points of agreement
What really galls Plantinga. are the views of people like Dawkins and Provine who not only insist that evolution is a proven "fact," but suppose that this somehow undercuts the reasonableness of any sort of belief in a Creator. Their argument hinges on the notion of design. The role of the Creator in traditional religious belief was that of Designer; the success of the theory of evolution has shown that design is unnecessary. Hence, there is no longer any valid reason to be a theist. In a recent review of a history of the creationist debate in the U.S., Provine lays out this case, and concludes that Christian belief can be made compatible with evolutionary biology only by supposing that God "works through the laws of nature" instead of actively steering biological process by way of miraculous intervention. But this view of God, he says, is "worthless," and "equivalent to atheism."3 (On this last point, Plantinga and he might not be so far apart!) He chides scientists for publicly denying, presumably on pragmatic grounds, that evolution and Christian belief are incompatible; they must, he says, know this to be nonsense.
Plantinga puts his finger on an important point when he notes that for someone who does not believe in God, evolution in some form or other is the only possible answer to the question of origins. Prior to the publication of The Origin of Species in 1859, the argument from design was part of biological science itself. The founders of physico-theology two centuries earlier, naturalists like John Ray and William Derham, had shown the pervasive presence in Nature of means-end relationships, the apparently purposive adjusting of structure and instinctive behavior to the welfare of each kind of organism. Someone who rejected the idea of God had, therefore, to face some awkward problems in explaining some of the most obvious features of the living world; it seemed as though science itself testified to the existence of God.4
Darwin changed all this. He made it possible to reconcile atheism with biological science; from then onwards, the fortunes of atheism as a form of intellectual belief would depend upon the fortunes of the theory of evolution. No wonder, then, that evolution became a crucial "myth" (as Plantinga puts it) of our secular culture, replacing for many the Christian myth as "a shared way of understanding ourselves at the deep level of religion."5 No wonder also that an attack on the credentials of evolutionary theory would so often evoke from its defenders a reaction reminiscent in its ferocity of the response to heresy in other days.
Is evolution fact or theory? No other question has divided the two sides in the creation-science controversy more sharply. Plantinga notes that someone who denies the existence of a Creator is left with no other option for explaining the origin of living things than an evolutionary-type account. It thus, equivalently, becomes "fact" not just because of the strength of the scientific evidence in its favor but because for the atheist no other explanation is open. On the other side, the believer in God is going to resent this use of the word, "fact," because it seems to exclude in principle the possibility of a Divine intervention, and hence by implication, the possibility of the existence of a Creator. "Fact" seems to convey not just the assurance of a well-supported theory, but the certainty that no other explanation is open.
The debate may often, therefore, be something other than it seems. Instead of being just a disagreement about the weight to be accorded to a particularly complex scientific theory in the light of the evidence available, the debate may conceal a far more fundamental religious difference, each side appearing to the other to call into question an article of faith. To religious believers, calling the assertion of common ancestry a "fact" appears to violate good scientific usage; no matter how well-supported a theory may be (they argue), it remains a theory. To non-believers, the phrase "merely a theory" comes as a provocation, because it suggests a substantial doubt about a claim that appears to them as being beyond question, a doubt prompted furthermore in their view by an illegitimate intrusion of religious belief.
At one level, then, Plantinga's essay can be read as a plea for a more informed understanding of the real nature of the creation-science debate, and a more sympathetic appreciation of what led the proponents of creation-science to take the stand they did. Even their defense of a "young" earth (the major point of disagreement between his view and theirs) ought not (he says) be regarded as "silly or irrational." One need not be "a fanatic, or a Flat Earther, or an ignorant Fundamentalist" to hold such a view. The claim that the earth is ancient is neither obvious nor inevitable; it has to be argued for, and disagreement may, therefore, easily occur.
Plantinga is right, to my mind, to see more in the creation-science debate than evolutionary scientists (or the media) have been wont to allow. And the sort of challenge he offers to the defenders of evolution, though it is not new, could serve the purposes of science in the long run if it forced a clarification and strengthening of argument on the other side, or if it punctured the sometimes troubling smugness that experts tend to display when dealing with outsiders. Plantinga leans too far in the other direction, however. The charitable reading of creation-science that he urges could easily mislead. A claim does not have to be obvious or inevitable for its rejection to connote fanaticism or ignorance. If the indirect evidence for the great age of the earth is overwhelming (Plantinga himself allows that it is "strong"), if its denial would call into question some of the best-supported theoretical findings of an array of natural sciences (cosmology, astrophysics, geology, biology), then one is entitled to issue a severe judgment on the challenger. Perusal of works like that of Morris would lead one to suspect that no matter how strong the scientific case were in favor of an ancient earth, it would make no difference to their authors. Their implicit commitment to a literalist interpretation of Genesis is such that it blocks a genuinely rational assessment of the alternative. The term, "fanatic," is a notoriously difficult one to apply fairly, because it conveys moral, as well as epistemic, disapprobation. But I would be willing to defend its appropriateness to such expositions of creation-science as that of Morris.
What bothers Plantinga, I suspect, about the use of the term here, is that from his point of view the creation-scientist's heart is in the right place, even if perhaps his head isn't. Anyone who stands up for "sola Scriptura" in the modern world, even in contexts as unpromising as the debate about the age of the earth, ought not (he seems to suggest) simply be dismissed. Creation-scientists may be wrong in holding that the earth is only a few thousand years old, but their motivation for making this claim ought be regarded with sympathy by their fellow-Christians, I would disagree, but it is because of a deeper disagreement about the merits of the "sola Scriptura" premise and of the remaining major theses of creation-science. Though I would not be as harsh on the creation-scientist as leading evolutionists have been, I would, as a Christian, want to register disapproval of creation-science at least as strong as theirs, though for reasons that go beyond theirs. These reasons will become clear, I hope, in what I have to say about Plantinga's analysis of what happens when "faith and reason clash."
3. Galileo and Genesis
In his Letter to the Grand Duchess Christina (1615), Galileo gave the most extended account that anyone perhaps had written up to that time of how the Christian should proceed when an apparent conflict between science and Scripture arises. Aided, doubtless, by some of his theologian-friends, he drew upon Augustine, Jerome, Aquinas, and an impressive array of other authorities, in order to show that the use made of Scripture by those who opposed the Copernican theory was illegitimate.6 There may be some lessons to be drawn from this historic document in the context of the Darwinian debate, apart from the obvious one of the embarrassment that the Church would later suffer because of its ill-advised attempt to make the geocentric cosmology of the Old Testament authors a matter, equivalently, of Christian faith.
What, then, did Galileo hold about the bearing of the Scriptures on our knowledge of the natural world? It does not take long for the reader to discover that two radically different principles are proposed in different parts of the Letter, and to realize that Galileo almost certainly was not aware of the resulting incoherence.7 On the one hand, he cites Augustine in support of the traditional view that in cases of apparent conflict, the literal interpretation of Scripture is to be maintained, unless the opposing scientific claim can be demonstrated. In that case, theologians must look for an alternative reading of the Scriptural passage(s), since it is a first principle that faith and natural reason cannot really be in conflict. However, the straightforward interpretation of Scripture is to be preferred in cases where the scientific claim has something less than "necessary demonstration" in its support, because of the inherently greater authority to be attached to the word of God.8
On the other hand, Galileo also argues that one should not look to Scripture for knowledge of the natural world: the function of the Bible is to teach us how to go to heaven, not how the heavens go, in the aphorism attributed to Baronius. God has given us reason and the senses to enable us to come to understand the world around us. Attempting to teach the underlying structures of natural process would have baffled the readers of Scripture and defeated its obvious purpose. Galileo produced a number of convergent lines of argument to the effect that Scripture is simply not relevant to the concerns of the sciences to begin with.
The implications of these two quite different hermeneutic principles were, of course, altogether different for the resolution of the Copernican debate.9 But that is not my concern here. More to my purpose is to note that the first principle has one quite disastrous consequence: it sets theologians evaluating the validity of the arguments of the natural philosophers, and natural philosophers defending themselves by composing theological tracts. Either way, there will be immediate charges of trespass. The theologian challenges the force of technical scientific argument; scientists urge their own readings of Scripture or their own theories as to how Scripture, in general, should be read. In both cases, the professionals are going to respond, quite predictably: what right have you to intrude in a domain where you lack the credentials to speak with authority? The assessment of theory strength is not a simple matter of logic and rule but requires a long familiarity with the procedures, presuppositions, and prior successes of a network of connected domains, and a trained skill in the assessment of particular types of argument.
Transposing from the Galilean to the Darwinian debate demands some care, yet there are obvious morals to be drawn. Neither of Galileo's principles is entirely adequate for regulating disputes of this general kind. One ought not require that a scientific case be demonstrative before it have any standing in the face of an apparently contrary Scriptural assertion. On the other hand, one cannot (as Plantinga correctly says) simply rule out conflicts of this kind by laying down that Christian doctrine can have no implications for matters that fall under scientific jurisdiction. Galileo was right to maintain that the Bible was not intended as (in part) a manual of natural knowledge. The biblical writers simply made use of the language and the cosmological beliefs of their own day while telling the story of human salvation. But that story itself does require certain presuppositions about human nature, about freedom and moral responsibility, for example, that would clash with psychological theories affirming the unreality of our claim to freedom of moral action. So it is not as though the two domains are, in principle, so safely walled off from one another that no conflict can possibly arise.
Nevertheless, Scripture scholars would be in a large measure of agreement today that the domain of such potential conflict is quite limited. In particular, the creation narratives of the first two chapters of Genesis are not to be read as literal history. The points they are making lie deeper and can only be reliably discerned by investigating the wider literary context of that day, on the one hand, and the later theological appropriations of those narratives, on the other.10 It is not as though the texts are to be taken literally unless and until a conclusive scientific account of origins can be constructed. Rather, no likelihood is to be attached in the first place to the literal construal of the story, say, of the separate creation of the animals. To interpret it literally or quasi-literally is to misunderstand the point hat the writers of those narratives were trying to make, the great majority of contemporary Scripture scholars would agree.11
An interesting feature of Plantinga's argument is that he explicitly brackets the reference to Genesis that one would expect to find, given the primacy he accords to Scripture. Did he originally plan to return to the text of Genesis at the end of his paper to clinch his case? ("Suppose we temporarily set to one side the evidence, whatever exactly it is, from early Genesis.") I kept waiting for him to turn finally to the biblical narratives of creation as the strongest reason for distrusting the evolutionary story. Historically, these narratives provided the main warrant for the traditional Christian belief that God intervened in a special way to bring to be the first members in the lineage of each natural kind. Those who, like Plantinga, have urged the superiority of special creation over evolution have almost always relied upon a direct appeal to Genesis, unless (as we have seen) they were prevented, as the recent creation-science advocates were, by political constraints.
Plantinga is under no such constraints, however. Since he evidently believes that a case can be made for special creation without any overt appeal to Genesis, he may have felt it better to avoid the controversies that surround the literalist approach to the Genesis text. He already has the scientists on his hands. Why open a second front and take on the theologians too? There is no rhetorical advantage to be gained by making explicit that he can expect little support for the thesis of special creation on the part of contemporary biblical scholars.
Despite his silence in regard to Genesis, I do not think that a linkage between his argument and the more traditional Genesis-based argument can be denied. Without the latter, would anyone think it a priori more likely that the God of the salvation story would intervene to originate natural kinds instead of allowing them to appear gradually and in a "natural" way? And if biblical theologians are right in holding that the cosmological references in the Old Testament ought be understood as conveying fundamental theological truths about the dependence of the natural and human worlds on their Creator, rather than explaining how exactly these worlds first took shape, then perhaps one ought be just as wary of drawing a cosmological moral from the salvation story as a whole as from the controversial passages in Genesis.
What must be disputed, to my mind, is a modern analogue of the first of Galileo's principles,12 which would, equivalently, reaffirm the presumption that the biblical text was partially intended as a cosmology, so that in cases of apparent conflict between the biblical and current scientific accounts we should evaluate the strength of the scientific account as a means of deciding which of the two "competitors" to accept. Plantinga proposes such a "balancing of likelihoods" methodology: a literalist understanding of God's making of the ancestors of the main natural kinds, he concludes, should be preferred unless and until a far stronger case can be made for the evolutionary alternative.
What I am urging is that it is potentially destructive (as the Galileo case amply shows) to treat the biblical and the scientific as competitors in the realm of cosmological explanation. The cosmological implications (if any) of the Scripture story are to be discovered by theological study, not be assessing the credentials of the supposedly competing scientific account. Even if the theory of evolution could be entirely dismissed on scientific grounds, this would not of itself give us any warrant for supposing that the biblical account of origins ought, therefore, be taken literally. It might well be that, in the absence of a plausible evolutionary account the only reasonable alternative for the Christian would be something like special creation. But even this would not warrant the supposition that special creation, in the literal sense, is what we ought properly infer from the biblical texts, whether the accounts of Creation in Genesis, or the story of Israel leading up to the coming of Christ. The interpretation of these texts is primarily a hermeneutic problem for the theologian; criticism of supposedly competing scientific theories will rarely be relevant.13
Where the theologian is unsure of the best interpretation to give a text, it is not inappropriate, of course, to take into account that some of the possible interpretations may be closed off by the findings of the natural or social sciences. But even in such a case (as Augustine's own practice might easily be made to illustrate) primary weight should be given to the hermaneutic issue as to what the disputed text was originally intended to convey and the theological issue of what the tradition has made of it. This way of handling relationships between Scripture and the sciences does not close them off from one another entirely, as we have already seen. But it encourages us to resist the temptation to construe the two as normally belonging to the same order of explanation or historical claim. As an illustration of how Scripture could "correct current science," Plantinga remarks: "If, for example, current science were to return to the view that the world has no beginning, and is infinitely old, then current science would be wrong."14 I do not believe that Scripture does prescribe that the universe has a beginning in time, in some specific technical sense of the term, "time"; the point of the Creation narratives is the dependence of the world on God's creative act, to my mind, not that it all began at a finite time in the past.15 A world that has always existed would still require a Creator.
4. The Thesis of Common Ancestry
Plantinga dismisses the evidence ordinarily presented in support of what he calls the Thesis of Common Ancestry (TCA) as inconclusive, after a rather cursory review. His conclusion: "It isn't particularly likely, given the Christian faith and the biological evidence, that God created all the flora and fauna by way of some mechanism involving common ancestry." Though my "disagreement with him centers especially on the conclusion he draws from Christian faith in regard to the antecedent likelihood of special creation, I am going to spend some time on the scientific issues first. The credentials of a thesis encompassing as much of past and present as TCA does cannot, of course, be dealt with satisfactorily in a few pages. 16 This is particularly true when these credentials are being denied, contrary to the firm conviction of the great majority of those professionally engaged in the many scientific fields involved.
Though a full-scale defence of TCA cannot be attempted here, and would in any event be beyond my competence, it may be worthwhile to indicate how in a general way such a defence might proceed.17 First, an important distinction, one alluded to by Plantinga. TCA is a historical claim that the kinds of living things originated somehow from one another. On the other hand, the various theories of evolution are an attempt to explain how that could have occurred.18 The dominant theory of evolution at the present time is the so-called "modern synthesis," associated with such figures as Simpson, Dobzhansky, and Mayr. It has its critics: Goldschmidt and Schindewolf a generation ago, for example, Gould and Kimura today. Though all of these have found fault with the Darwinism of the modern synthesis and have proposed alternatives to it, none would for a moment question TCA. Their confidence in TCA does not depend, then, on a similar degree of confidence in the explanatory adequacy of a specifically Darwinian account of the origin of species. Is it, perhaps, that they implicitly reject God's existence, and thus TCA is for them (in Plantinga's phrase) "the only game in town?" I don't think it is quite as simple as this, although the implicit setting aside of a theistic alternative obviously could play a role.
Much of the evidence for TCA functions independently of the detail of any specific evolutionary theory. Plantinga mentions three such categories of evidence, so I will confine myself to those. There is the fossil record which has already yielded innumerable sequences of extinct forms, where the development of specific anatomical features can be traced in detail through the rock-layers. Paleontologists have traced the development of eyes in no less than forty independent animal lineages ("lineages" being determined by overall morphological similarities).19 They continue to uncover stage after stage in crucial "linking" forms, such as the therapsids, for example, the forms that relate reptiles with the earliest mammals. In cases like these (and there are a lot of them), paleontologists can point to a variety of morphological features that gradually shift over time, retaining a basic likeness (a so-called Bauplan) throughout. Gould's objection regarding the rarity of transitional forms (quoted by Plantinga) has to be taken in context. Gould would not deny the morphological continuities of the fossil record; like thousands of other researchers he has given too much of his time to tracing these continuities for him to underrate their significance. What he would say (and what many defenders of the modern synthesis would now be disposed to admit) is that species often make their appearance in the record without the prior gradual sequence of modifications one would have expected from the traditional gradualist Darwinian standpoint. But this leaves untouched the implications, overall, of the fossil record for TCA. It does, of course, affect the sort of theory that could account for the sequence found in the record.20
Instead of scrutinizing the fossil record, we might look to the living forms around us, and there discover all sorts of homologies and peculiar features of geographical distribution, which are best understood in terms of TCA. The arguments here are long familiar and I will not dally on them. But there is a further category of evidence which has taken on a great deal of importance in the last twenty years. This comes from molecular biology.21 Comparison of the DNA, as well as of the proteins for which DNA codes, between different types of organisms shows that there are striking similarities in chemical composition between them. Cytochrome C, for example, found in all animals, is involved in cell respiration. It contains 104 amino-acids, in a sequence which is invariable for any given species. For humans and rhesus monkeys, the sequence is identical except in one position; for horses and donkeys the sequence also differs in only one position. But for humans and horses, the difference is 12; for monkeys and horses, the difference is 11. If instead of cytochrome C another homologous protein is chosen, similar (though not necessarily identical) results are found. These very numerous resemblances and differences between the macromolecules carrying hereditary information can be explained by supposing a very slow rate of change in the chemical sequences constituting these molecules, and thus a relationship of common descent among the organisms themselves. Thus, the "molecular" differences between any two species become (on this hypothesis) a rough indication of how long since the ancestors of these species diverged; rather more securely, one can infer the relative order of branching between three or more species; one can infer whether A branched from B before C did. What is impressive here is the coherence of the results given by examining many different macromolecules in this light.
But much more impressive is that these results conform reasonably well with the findings of both paleontology and comparative anatomy in regard to the ancestral relations between species, the postulated tree of descent that had already been worked out in some detail in these other disciplines. The fit, as one would expect, is not exact in each case in regard to the "closeness" between the species, but it is nevertheless quite good. When a single explanatory hypothesis (TCA) underlies the binding together of three domains so diverse in character, we have the sort of consilience that carries more weight with scientists than does, perhaps, any other virtue of theory.
It should be underlined that specific theories of evolution are not yet involved here. The support given TCA by these diverse types of evidence does not depend any particular explanatory account of how species-change takes place. One could reject natural selection as the primary agent of evolutionary change, for example, and still find this argument for TCA convincing.22 Of course, a satisfactory explanatory account of how evolutionary change occurred would greatly strengthen the case for TCA. But in the light of the continuing debates about the adequacy of this or that feature of the neo-Darwinian model, it is important to stress that there is a vast body of evidence for common descent that does not depend for its logical force on the further issue of how exactly the transitions from one life-form to another came about.
Plantinga raises one objection that bears on TCA directly. Does there not seem to be an "envelope of limited variability" surrounding each species, so that a deviation of more than a small amount from the central species-norm leads to reversion or sterility? Would one not expect to find evidence of new species now and then appearing in the present (or perhaps being deliberately produced) if indeed TCA is true? The first and simplest response is to note that in the plant world (in the forest, for example) new species have indeed been observed. And the production of fertile hybrids is an important part of agricultural research. The ability of populations of microorganisms to alter their structures quite basically over relatively short times under the challenge of antibiotics is all too well-known. But defenders of the modern synthesis themselves insist on the extraordinary stability of the genotype, in the animal realm particularly; this stability is essential to the maintenance of species differences, and some progress has been made toward an understanding of its molecular basis in the constellations of genes.
TCA does not require rapid change. The presumption is that the kind of species-change that would sustain TCA could take thousands of generations to accomplish. The rate of change required (as has been shown in detail in recent studies in population genetics) is far too slow for the sort of direct evidence to accumulate that Plantinga is asking for. But even more fundamentally, there are serious problems with the species concept itself, the concept underlying this objection. Ought it, for example, be based on the morphological difference (of the kind that paleontologists or comparative anatomists can attest to), or ought it be based on interbreeding boundaries (as naturalists have long preferred to maintain)?23If we were to find the fossil remains of animals as different as a St. Bernard and a Chihuahua in the rock strata, we should assuredly label them as different species. But if we adopt the biological species concept according to which "species are groups of interbreeding natural populations that are reproductively isolated from other such groups,"24 how are we to apply this to populations that are widely separated in space or time? Mayr emphasizes that such application always involves complex and indirect forms of inference.25 The moral is not that the species-concept is so ambiguous as to be unusable, but only that such notions as species-change are far more difficult to handle than at first sight they seem to be. And more specifically, the claim that an "envelope of limited variability" surrounds each species has no precise empirical foundation.
I suspect that in the end this claim simply begs the question against TCA. It asserts that the sort of change TCA would require does not occur. But this is just the issue, and this is what is challenged by the three kinds of evidence described above, all of them pointing to TCA as the most reasonable explanation. What does Plantinga make of these? He deals with them, to my mind, in a quite unsatisfactory way: "Well, what would prevent [God] from using similar structures?", referring to the argument from homologies; and: "As for the similarity in the biochemistry of all life, this is reasonably probable on the hypothesis of special creation." Any attempt to reconstruct the past on the basis of traces found in the present can, of course, always be met with the objection: but God could have disposed matters so as to make it look as though it happened that way, even though it didn't. If TCA is correct, one would expect the sort of coherences that molecular biology is now turning up in such abundance. I can see no reason whatever to suppose that the hypothesis of special creation would antecedently have led us to expect this same range of evidence. Recalling the lines of a famous debate long ago about fossils, the God of the Christian tradition is surely not one who would deceive us by strewing around what would amount to misleading clues!
Let me stress once again the criterion of consilience. Evidence from three quite disparate domains supports a single coherent view of the sequence of branchings and extinctions that underlie TCA. If TCA is false, if in fact the different kinds of organisms do not share a common ancestry, this consilience goes entirely unexplained. It is all very well to say: "but God could have...." This hypothesis leaves the consilience exhibited by TCA an extraordinary coincidence. So it is not as though allowing the theistic alternative into the range of possible explanations alters the balance of probability drastically, as Plantinga supposes. TCA is, of course, an hypothesis, as any reconstruction of the past must be. But it remains by far the best-supported response, even for the theist, to the fast-multiplying evidence available to us.
5. Theories of evolution
What about the objections to the neo-Darwinian theory of evolution, as such, as distinct from TCA? Plantinga outlines a familiar objection to any theory which relies on natural selection as the primary mechanism of evolutionary change. There is no plausible evolutionary pathway (he argues) linking an eyeless organism, say, with an organism possessing the complex structures of the mammalian eye, such that every single stage along the way can be shown to be adaptively advantageous. This is the oldest of objections to Darwin's theory; it was the primary criticism raised by Mivart in his Genesis of Species (1871). Darwin's own first response was to emphasize that his theory did not rely on natural selection alone.26
Among the other processes that he proposed, one in particular
is still emphasized: change of function, where a structure that originally
developed because of the adaptive advantage offered by one particular function
takes on (especially under the impact of change of habitat or the like) a new
function. Another process whose importance has only recently come to be
recognized is genetic drift. In the isolated and often small populations that
furnish the likeliest starting-point for the speciation-process, there can be a
sort of genetic random sampling error that eventually marks off the smaller
population from the parent population. And there can be "hitchhiker"
effects of all sorts due to genetic linkage. These processes do not operate independently of natural selection, but they can easily bring about results that the adaptive-advantage-at-every-step model of evolutionary change could not.27 Defenders of the modern synthesis are as quick as Darwin was to insist that they are not limited in their explanatory strategies to the selectionist model only.28
Nevertheless, to some critics of the modern synthesis, these concessions are not enough. Gould, for example, has criticized what he calls the "adaptationist program" for its failure to take seriously the many alternatives to trait-by-trait selection on the basis of adaptive advantage. As his own favorite alternative he notes the constraints that the integrity of the structure of the organism as a whole sets on the possible pathways of change, so that the outcome is explicable rather more by the nature of the constraints than by the application of selectionist norms to individual traits.29 Kimura has developed a controversial molecular level theory according to which most changes in gene frequencies are of no selective advantage, but are neutral. More radical challenges come from those who rely on macromutations (saltations) to bridge major discontinuities in the fossil record; theories of this sort, it is genera
Where does all this leave us? The confidence of the defenders of the modern synthesis is based on the substantial explanatory successes of their model. They have no illusions about having explained everything; in particular, they concede that the processes responsible for the origin of the main
phyla are not well understood.31 Their explanatory model has already been
substantially reshaped over the last fifty years, while retaining the original
emphasis on the transformative powers of selection operating on individual
differences. Undoubtedly, more such reshaping lies ahead. Like any other active
scientific theory, the modern synthesis is incomplete, but its exponents argue,
in great detail, that there are no in-principle barriers to its continued
successful extension to the difficult cases. A minority has proposed that a more
radical transformation is needed, one which abandons either the gradualism or
the heavy reliance on selection that have marked the Darwinian approach.32 The
most extreme view is represented by Michael Denton, who argues that all current
theories of evolution are in principle inadequate to handle macroevolution, and
that we have to await another quite different sort of theory. Where does the burden of proof lie in a matter of this sort?
The claim that principles of a broadly Darwinian sort are capable of explaining
the origins of the diversity of the living world rests on the successes of the
theory to date. These are very considerable; they span many fields and have
shown intricate linkages between those fields. In particular, the theory has
shown an extraordinary fertility as it has been extended into new domains; even
when it has encountered anomalies, it has shown the capacity to overcome these
in creative ways that are clearly not ad hoc.33 This is the sort of thing that
impresses those who are actually in touch with the detail of this research. And
it gives a prima facie case for supposing that the theory can be further
extended to contexts not yet successfully treated. But, of course, this cannot
in the strong sense be proved; it can only be made seem more (or less)
plausible. On the other side is the claim that theories of a Darwinian
type are in principle incapable of handling certain classes of data: gaps in the fossil record, the origin of complex organs like the eye, the origin of the
broad divisions of the living world (the phyla), or the like. Claims of this
sort are hard to establish because they cannot anticipate the trajectory that the theory itself may
follow as it is reworked in the light of new challenge. (Could the changes of the
last
century leading up to the modern synthesis have been foreseen?) This is not to say
that such claims can never be established, or at least shown to be strongly
supported. So it is not that the burden of proof falls to one side rather than the other.
Rather, it is a matter of weighing up the merits of the case on each side, and making some kind of comparative assessment, informed by parallels from the earlier
history of science, and a very detailed knowledge of the history and
contemporary situation of the various fields where the evolutionary paradigm is applied. Plantinga formulates a second sort of objection to theories of
evolution in general: they can never tell the whole story of the genetic
changes involved, the rates of mutation, the links between gene adaptation, and so
forth: "Hence we don't really know whether evolution is so much as biologically
possible." But first of all, evolutionary explanation begins at the level of the
biological individual and the population, not the gene; natural selection operates on
adaptations of whose genetic basis we may be (and usually are) entirely unaware.
And the explanation is none the less real for that. But, more important,
evolutionary explanation is of its nature historical, and historical explanation is not like
explanation in physics or chemistry. It deals with the singular and the
unrepeatable; it
is thus necessarily incomplete. One must be careful to apply the appropriate criteria when assessing
the merits of a particular explanation. An evolutionary
explanation can never be better than plausible; the real problem lies in
discriminating between different degrees of plausibility. The dangers of settling for a very
weak sort of plausibility are real (Gould's "just so" stories). But the
dangers of requiring too strong a degree of confirmation before allowing any standing to an
evolutionary explanation ("Hence we don't really know...") are just as great.
The presumed inadequacy of current theories of evolution is
part of what leads Plantinga to propose his own alternative. What exactly is it?
Is it that God brought to be in a miraculous way each of the millions of
species that have existed since life first appeared on earth? More than 99.99% of
these are now extinct. May one ask why God would have created them? The
thesis that Plantinga deems more probable than TCA is simply that "God
created mankind, as well as many kinds of plants and animals, separately and
specially." Perhaps he means that God just created the phyla (including
the ones that have gone extinct?). As we have seen, it is the manner in which
the major divisions of the living world came to be that has provided the theory
of evolution with its largest challenge. But why not all species? How is
Plantinga to decide just which thesis is more probable than TCA? Presumably by
checking to see what evolutionary theory has, in his view, been able to explain
successfully. And then whatever is left over, God is more likely to have brought
about miraculously. God of the gaps? It certainly sounds like that.
Whatever
science cannot currently explain, or, more exactly, whatever one can make a
case for holding that science could never in principle explain, is to be deemed
the "special" work of God. One is reminded of eighteenth century
natural theology. But Plantinga's intent is not apologetic, as that of natural
theology was. It is not that he is using the supposed gaps in evolutionary explanation to support belief
in the existence of a God who could plug the gaps. Rather, he considers it
antecedently probable that God would intervene in ways like this; his critique of
evolutionary theory is intended to locate the spots at which He is most likely to
have intervened. Whenever evolutionary theory is unable to explain in a totally
convincing way the origins of a particular kind, the hand of God is to be seen at
work. Plantinga claims that the Christian believer "has a
freedom not available to the naturalist," because he or she is "free to look
at the evidence ... and follow where it leads." This might be correct if he were to hold
only that the believer holds open an extra alternative that allows him or her to be
more critical of the shortcomings of the scientific theory. But he holds something
much stronger than that: there is an antecedent likelihood of "special"
intervention of this kind in cosmic process, and hence unless the scientist has a strong
case, the hypothesis of Divine intervention has to be allowed the higher likelihood.
Recall the two hermeneutic principles sketched by Galileo: the
"confrontation" principle suggests that unless a clear case can be made for the scientific
theory, the theological alternative should take preference. I am not sure that this
does in the end allow the Christian believer more freedom than the naturalist. But
whatever of that, it certainly ensures conflict; it is likely to maximize the
strain between faith and reason. 6. The integrity of God's natural world Plantinga's argument relies first and foremost on the premise
that God's "special" intervention in cosmic process is antecedently
probable. Here is where he and I really part ways. My view would be that from
the theological and philosophical standpoints, such intervention is, if
anything, antecedently improbable. Plantinga builds his case by recalling that
"according to Scripture, [God] has often intervened in the working of his
cosmos." And the examples he gives are the miracles of Scripture and the
life, death, and resurrection of Jesus Christ. I want to recall here a set of
old and valuable distinctions between nature and supernature, between the order
of nature and the order of grace, between cosmic history and salvation history.
The train of events linking Abraham to Christ is not to be considered an
analogue for God's relationship to His creation generally. The Incarnation and
what led up to it was unique in its manifestation of God's creative power and
His loving concern for His universe. To overcome the consequences of human
freedom, a different sort of action on God's part was required, a transformative
action culminating in the promise of resurrection for the children of God,
something that (despite the immortality claims of the Greek philosophers) lies
altogether outside the bounds of nature. The story of salvation is a story about men and women, about
the burden and the promise of being human. It is not about plants and animals;
it provides no warrant whatever for supposing that God would have brought the
ancestors of the various kinds of plants and animals to be outside the ordinary
order of nature. The story of salvation does bear on the origin of the first
humans. If Plantinga were merely to say that God somehow "leant" into
cosmic history at the advent of the human, Scripture would clearly be on his side. How this "leaning" is to be interpreted is, of course, another matter.34 But his claim is a much stronger one. To carry the argument a stage further: what would the eloquent
texts of Genesis, Job, Isaiah and the Psalms lead one to expect?
What have theologians made of these texts? This is obviously a theme that far
transcends
the compass of an essay such as this one. I can make a couple of simple points.
The Creator whose powers are gradually revealed in these texts is omnipotent and
all-wise, far beyond the reach of human reckoning. His Providence extends to
all His creatures; they are all part of His single plan, only a fragment
of which we know, and that darkly. Would such a Being be likely to
"intervene" in His creation in the way that Plantinga describes? (I am uncomfortable with this
language of "likelihood" in regard to God's action, as though we were somehow capable
of catching the Creator of the galactic universe in the nets of our
calculations. But let that be.) If one can use the language of antecedent probability at all
here, it surely must point in the opposite direction. St. Augustine is the most significant guide, perhaps, to the
proper theological response to this question. He was the first to weave from
biblical texts and his own best understanding of the Church's tradition the full
doctrine of creation ex nihilo, as Christians understand it today. And in the
De
Genesi ad litteram, his commentary on the very texts in Genesis where the writer
speaks of the coming to be of the plant and animal world on the fifth and sixth
"Days" of Creation, he enunciated the famous theory of the rationes
seminales, the
seed-principles which God brings into being in the first moment of creation, and out
of which the kinds of living things will, each in its own time, appear.35 The
"days," said Augustine, must be interpreted metaphorically as indefinite periods of
time. And instead of God inserting new kinds of plants and animals ready-made, as
it were, into a preexistent world, He must be thought of as creating in that very
first moment the potencies for all the kinds of living things that would come
later, including the human body itself: In the seed, then, there was
invisibly present all that would develop in time into a tree. And in this same
way we must picture the world, when God made all things together, as having had
all things which were made in it and with it when day was made. This includes
not only the heavens with sun, moon, and stars ... but also the beings which
water and earth contained in potency and in their causes, before they came forth
in the course of time.36 Augustine, for one, would not have attributed an antecedent
probability to God's "intervening" to bring the first kinds of plants
and animals abruptly to be, rather than having them develop in the gradual way
that seeds do. But what are we to make of Plantinga's objection that having
life coming gradually to be according to the normal regularities of natural
process is "semi-deistic," that it attributes too much autonomy to the
natural world? He says: God could have accomplished this creating in a thousand
different ways. It was entirely within his power to create life in a way
corresponding to the Grand Evolutionary Scenario ... to create matter ...
together with laws for its behavior, in such a way that the inevitable37 outcome
of matter's working according to these laws would be first, life's coming into
existence three or four billion years ago, and then the various higher forms of
life, culminating as we like to think, in humankind. This is a semi-deistic view
of God and his workings. He contrasts this alternative with the one he favors: Perhaps these laws are not such that given enough time, life
would automatically emerge. Perhaps he did something different and special in
the creation of life. Perhaps he did something different and special in creating
the various kinds of animals and plants. His characterization of the first alternative as
"semi-deistic" is intended to validate the second alternative as the
appropriate one for the Christian to choose. But why should the first
alternative be regarded as semi-deistic? He allows that it was within God's
power to bring about cosmic evolution, but then asserts that to say He did in
fact fashion the world in this way would be semi-deistic. This is puzzling. It
would be semi-deistic in an extended sense perhaps, if we already knew that God
had intervened in bringing to be some kinds of plants and animals, in which case
the "Grand Evolutionary scenario" would attribute a greater degree of
autonomy to the natural world than would be warranted. But this is exactly what
we don't know. And to assume that we do know it would beg the question. The problem may lie in the use of the label,
"semi-deistic." A semi-deist, Plantinga remarks, could go so far as to
allow that God "starts everything off," and "constantly sustains
the world in existence," and even maintain that "any given causal
transaction in the universe requires specific divine concurrent activity."
All this would, apparently, not be enough to make such a view orthodox from the
Christian standpoint. What more could be needed? Defining God's relationship
with the natural order in terms of creation, conservation, and concursus, has
after all been standard among Christian theologians since the Middle Ages.
Perhaps what still needs to be made explicit is that God could also, if He so chose, relate to His creation in a different way, in the
dramatic mode of a grace that overcomes nature and of wonders that draw attention to His covenant
with Israel and ultimately to the person of Jesus. The
possibility of such an "intrusion" on God's part into human history, of a
mode of action that lies beyond nature, must not be excluded in advance, must indeed be
affirmed. I take it that the denial that such a mode of action is possible on the part
of the Being who creates and may even also conserve and concur is what
constitutes semi-deism, in Plantinga's sense of that term. But someone who asserts that the evolutionary account of
origins is the best supported one is not necessarily a semi-deist in this sense.
Some defenders of evolution-notably those who deny the existence of a Creator
and are, therefore, not deists of any sort-would, of course, exclude special
creation in this in-principle way. But there is no intrinsic connection whatever
between the claim that God did, in fact, choose to work through evolutionary
means and the far stronger claim that He could not have done otherwise. Nor, of
course, is there any reason why someone who defends the evolutionary account of
origin should go on to deny that God might intervene in the later human story
in the way that Christians believe Him to have done. In sum, then, at least four alternatives would have to be
taken into account here. There are those who defend the evolutionary account of
origins, and, rejecting the existence of God, would (if pressed) say that
life could not possibly have come to be except through evolution. There may be those
who maintain that God created, conserves, and concurs in the activity of the
universe, but that He could not "intervene" in its history to bring new
kinds of animals and plants to be, for example. These (if there are any such) are the
semi-deists
Plantinga describes. Then there are those who prefer the evolutionary account of
origins on the grounds of evidence that this is in fact most probably the way
it happened, but are perfectly willing to allow that it was within the
Creator's
power to speed up the story by special creation of ancestral kinds of plants and
animals, even though (in their view) this was not what He did. This is a view that a
great many Christians from Darwin's day to our own have defended; it is the view I
am proposing here. It is not semi-deistic. And finally, there is the option of
special creation: that God did, in fact, intervene by bringing various kinds of living things suddenly to be. When Plantinga presents two alternatives only, the second
being that God might "perhaps" have intervened as defenders of
special creation believe He did, he must be supposing that the other alternative, the
"Grand Evolutionary scenario," is one that excludes such a "perhaps,"
i.e., that excludes, in principle, the possibility that God could have intervened in the natural
order. What I am challenging is this supposition. The Thesis of Common Ancestry
can claim, as we have seen, an impressive body of evidence in its own right. It
need not rely on, nor does it entail any in-principle claim about what God could or
could not do.38 So, finally, how should the Christian regard this thesis? Perhaps
better, since there are evidently "distinctive threads in the tapestry of
Christianity," in Plantinga's evocative metaphor, how might someone respond who sees
in the Christian doctrine of creation an affirmation of the integrity of the natural
order? TCA implies a cousinship extending across the entire living world, the sort of
coherence (as Leibniz once argued) that one might expect in the work of an all-powerful and all-wise Creator. The "seeds," in Augustine's happy metaphor, have been there from
the beginning; the universe has in itself the capacity to become what God destined it from the beginning to be as a human abode, and for all we know much else. When Augustine proposed a developmental cosmology long ago,
there was little in the natural science of his day to support such a venture. Now that has changed.
What was speculative and not quite coherent has been transformed, thanks to the labors of
countless workers in a variety of different scientific fields. TCA allows the Christian
to fill out the metaphysics of creation in a way that (I am persuaded) Augustine and
Aquinas would have welcomed. No longer need one suppose that God added plants here and
animals there. Though He could have done so, the evidence is mounting that the resources
of His original creation were sufficient for the generation of the successive orders of complexity that make up our worId. Thus, common ancestry gives a meaning to the history of life that
it previously lacked. In another perspective, this history now appears as preparation.
The uncountable species that flourished and vanished have left a
trace of themselves in us. The vast stretches of evolutionary time no longer
seem quite so terrifying. Scripture traces the preparation for the coming of
Christ back through Abraham to Adam. Is it too fanciful to suggest that natural
science now allows us to extend the story indefinitely further back? When Christ
took on human nature, the DNA that made him son of Mary may have linked him to a
more ancient heritage stretching far beyond Adam to the shallows of unimaginably ancient seas. And so, in the Incarnation, it would not have been just
human nature that was joined to the Divine, but in a less direct but no less
real sense all those myriad organisms that had unknowingly over the eons shaped
the way for the coming of the human.39 Anthropocentric? But of course: the story of the Incarnation
is anthropocentric. Reconcilable with the evolutionary story as that is told in
terms of chance events and blind alleys? I believe so, but to argue it would
require another essay. Unique? Quite possibly not: other stories may be
unfolding in very different ways in other parts of this capacious universe of
ours. Terminal? Not necessarily: we have no idea what lies ahead for humankind.
The transformations that made us what we are may not yet be ended. Antecedently
probable from a Christian perspective? I will have to leave that to the reader. Notes 1 The most obvious difference
scarcely needs be stated. Plantinga is one of the most highly respected
philosophers in the U.S., justly renowned for the quality of his scholarship and
the care and rigor of his arguments. I bracket him here with the
creation-science group, incongruous as such an association
may seem, only because of the broad similarity of their theses
in regard to special creation. I very much fear that this similarity may be
sufficient to encourage creation-scientists to co-opt his
essay to their own purposes. 2 For a taxonomy of the ways in
which faith and knowledge havebeen related by different Christian thinkers, see
James Kellenberger, Religious Discovery, Faith, and Knowledge, Englewood
Cliffs N.J.: Prentice-Hall, 1972, chap. 10. 3 William B. Provine, review of Trial and Error: The American Controversy over Creation and Evolution,
Academe, 73 (1),1987, pp. 50-52. 4 See McMullin, "The Rise and Fall of Physico-theology,"
section 4 of "Natural Science and Belief in a
Creator", in Physics, Philosophy, and Theology, ed. R. J. Russell et al., Rome: Vatican Observatory Press, 1988, pp. 63-67. 5 Plantinga is using the term "myth" here in a technical sense, he reminds us, one that should
not of itself be made to connote falsity or fiction. 6 Maurice Finocchiaro provides a new translation of the Letter in his The Galileo Affair, Berkeley: University of California Press, 1989, pp. 87-118. 7 Galileo introduces one further way of dealing with tensions
between Scripture and natural science, suggesting that the biblical authors
accommodated themselves to their hearers. This does not, in practice, reduce to
either of the principles above. The notion of accommodation had already been
hinted at by theologians as diverse as Thomas Aquinas and John Calvin. But this
is not the place for an exhaustive analysis of the logical complexities of the
famous Letter. See my "Galileo as a Theologian," Fremantle Lecture,
Oxford, 1983 (unpublished), and Jean Dietz Moss, "Galileo's Letter to
Christina: Some Rhetorical Considerations," Renaissance Quarterly, 36,1983, 547-576. 8 Finocchiaro, The Galileo Affair, p. 94. 9 See my Introduction to Galileo, Man of Science, New York: Basic Books, 1967, pp. 33-35. 10 There is an abundant literature on this topic. See, for
example, Robert Clifford S.J., "Creation in the Hebrew Bible," in Physics,
Philosophy, and Theology: A Common Quest for Understanding, ed. R. J. Russell,
W. R. Stoeger and G. V. Coyne S.J., Notre Dame: University of Notre Dame Press,
1988, pp. 151-170; Dianne Bergant CSA and Carroll Stuhlmueller CP, "Creation
according to the Old Testament," in Evolution and Creation, ed. E.
McMullin, Notre Dame: University of Notre Dame Press, 1985, pp. 153-175; Bernhard W.
Anderson, "The Earth is the Lord's: An Essay on the Biblical Doctrine of
Creation," in Is God a Creationist? ed. R. M. Frye, New York: Scribner,
1983, pp. 176-196. 11 There is a larger issue here of deciding on the proper
approach to Scripture generally. Plantinga characterizes the Reformed Christian
as one who takes "Scripture to be a special revelation from God
himself." Thus, for example, the story of Abraham, including the details of
where he lived and journeyed and how he came to father a son, becomes a matter
for history in the modem sense of that term, to be construed (in Plantinga's
view) as having the standing of science. There is an implicit literalist
presumption here that an Unreformed Christian like myself, someone
unsympathetic, that is, to the constraints of the "Sola scriptura"
maxim, would surely question. But to debate this would lead us far afield
indeed. 12 I am reluctant to label it "Augustinian," despite its obvious basis in the text of Augustine's De Genesi ad litteram. Augustine himself was not bound by it in practice. He did not require a conclusive demonstration over against the literal reading of the Six Days before abandoning such a reading and espousing a highly metaphorical one. And he stressed the importance of literary norms in general in the understanding of the import of the biblical text. The presumption in favor of literalism that we have seen to be the main source of conflict ("the text is to be interpreted literally unless a contrary reading can be established from an extrinsic source such as natural science") would be much more characteristic of later theology, notably the post-Reformation theology of Galileo's own day.
13 In his Letter to Christina, Galileo cited Augustine to warn
against the dangers of opposing "unbelievers" (read: experts) on the
basis of inadequate scientific knowledge (Finocchiaro, The Galileo Affair, p.
112). I suppose that this is what worries me most about the strategy Plantinga
urges on his Christian readers. Though he stresses the importance of scholarship
and the patient effort to understand, the reader who proceeds on his advice to
do battle with defenders of evolution all too easily risks causing the sort of
"laughter" that Augustine deplores, because of its negative effects on
the credibility of the Christian message generally. 14 As an illustration of how complex the notion of temporal
beginnings has become, the Hawking model does not imply that the universe is
infinitely old (as that phrase would ordinarily be understood) but rather that
as we trace time backwards to the Big Bang, the normal concept of time may break
down as we approach the initial singularity some fifteen billion years ago. The history of "real time" (as
Hawking calls it) would still be finite in the same terms as before, as he
explicitly points out (A Brief History of Time, New York: Bantam Books, 1988, p. 138). 15 The question of whether or not the time elapsed in cosmic
history is finite or infinite depends, in part, on the choice of physical
process on which to base the time-scale, particularly on whether it is cyclic or
continuous. The question of the finitude or infinity of past time, so much
debated by medieval philosophers and theologians, cannot straightforwardly be
answered in absolute terms. The notion of time-measurement is far more complex
and theory-dependent than earlier discussions allowed. But the theological point
of the biblical account of creation remains untouched by technical developments
such as this. See McMullin, "How Should Cosmology Relate to Theology?"
in The Sciences and Theology in the Twentieth Century, ed. A. R. Peacocke, Notre Dame: University of Notre Dame Press, 1981, p. 35. 16 As Plantinga himself recognizes: "There isn't the space
here for more than the merest hand waving... " But when the stakes are as
high as they become by the end of his essay, one may fairly question whether
hand waving is likely to be enough. 17 I would like to acknowledge my debt to the many who in
discussion have helped me overcome the bafflement that evolutionary theory
induces in the non-expert. In particular, my thanks go to Phil Sloan, Bill
Charlesworth, Francisco Ayala, Bob Richards, and John Beatty. 18 Plantinga distinguishes between the Thesis of Common
Ancestry and the attempt to explain common ancestry by some mechanism or other.
But he calls the latter "Darwinism," which might confuse, since non-Darwinian explanations of common ancestry have, of course, also been proposed. And he says that "TCA is what one most naturally thinks of as the Theory of Evolution." What he may mean here is that TCA is theoretical and it implicitly involves evolution in some guise. But it is preferable, I would suggest, not to equate TCA and "the Theory of Evolution" because for most readers "the" theory of evolution is Darwin's. 19 See L. von Salvini-Plawen and E.
Mayr, "On the Evolution of Photo-receptors and Eyes,"
Evolutionary Biology, 10, 1977, 207-263. 20 In his most recent discussion of the relation between microevolution and macroevolution, Mayr writes: "Almost every careful analysis of fossil
sequences has revealed that a multiplication of species does not take place through a gradual splitting of single lineages into two and their subsequent divergence but rather through the sudden appearance of a new species. Early paleontologists interpreted this as evidence
for instantaneous sympatric speciation [speciation over a single area], but it
is now rather generally recognized that the new species had originated somewhere
in a peripheral isolate and had subsequently spread to the area where it is
suddenly found in the fossil record. The parental species which had budded off
the neospecies showed virtually no change during this period. The punctuation is
thus caused by a localized event in an isolated founder population, while the
main species displays no significant change" (Toward a New Philosophy of
Biology, Cambridge, Mass.: Harvard University Press, 1988, p. 415). This theory
of allopatric speciation (speciation involving a second-in this case a
geographically isolated but adjoining-territory) allows Mayr to modify the
gradualism of the original Darwinian proposal, while retaining the basic
Darwinian mode of explanation and avoiding the (to him) objectionable
"punctual" events of the Gould-Eldredge scenario. But the debate is by
no means closed. 21For a brief review of this evidence, see Francisco Ayala,
"The Theory of Evolution: Recent Successes," in Evolution and
Creation, ed. E. McMullin, pp. 59-90. 22 In this regard, the position adopted by Michael Denton, perhaps
the most sweeping critic of evolutionary theory now writing, is quite puzzling. On
the one hand, he finds the sort of consilience described above altogether remarkable: "It became increasingly apparent as more and more sequences accumulated that the differences between organisms at a molecular level corresponded to a large extent with their differences at a morphological level; and that all the classes traditionally identified by morphological criteria could also be detected by comparing their protein sequences.... The divisions turned out to be more mathematically perfect than even the most die-hard typologists would have predicted" (Evolution: A Theory
in Crisis, Bethesda, Md.: Adler and Adler, 1986, pp. 276, 278). But the
distances between the molecular sequences characteristic of different species can
only be explained (he argues) by postulating a remarkably uniform "molecular
clock" marking the rate of change in the constituents of particular kinds of
molecules (and varying from one kind to another), and such a "clock" (he
maintains) is impossible to understand on neo-Darwinian principles. What would seem,
at best, to follow from this is that neo-Darwinian theory can't explain the
uniformity of the postulated "clock." But he assumes that he has also
refuted TCA, while providing no hint himself as to how the correspondences he finds so remarkable might be explained by something other than common ancestry. 23 These are only two of the many possibilities. There is an enormous literature on this topic. See, for example, the papers gathered in Section VII of Conceptual Issues in Evolutionary Biology, ed. Elliott Sober, Cambridge, Mass.: MIT Press, 1984, and E. Mayr, Animal Species and Evolution,
Cambridge, Mass.: Harvard University Press, 1963, pp. 400-423. 24 Mayr, Toward A New Philosophy of Biology (TNPB), p. 318. 25 A further problem is suggested by the notion of a
"natural" population. Reproductive isolation in the animal world is
due, in the first instance, to behavioral barriers, which are the main isolating
mechanisms (Mayr, TNPB, p. 320). Under artificial circumstances, such barriers
can be overcome, but this will not necessarily give rise to new biological
species. Likewise, deliberate interbreeding to produce new varieties of domestic
dog, for example, will not produce a natural population with its own behavioral
barriers to outbreeding. 26 Indeed, he showed some uncharacteristic indignation in his
comment in the last edition of the Origin of Species (1872): "As my
conclusions have lately been much misrepresented, and it has been stated that I
attribute the modification of species exclusively to natural selection, I may be
permitted to remark that in the first edition of that work, and subsequently, I
placed in a most conspicuous position-namely, at the close of the
Introduction-the following words: 'I am convinced that natural selection has
been the main but not exclusive means of modification.' This has been of no
avail. Great is the power of misrepresentation" (p. 395). 27 For a useful review, from the point of view of the modern
synthesis, see E. Mayr, "The Emergence of Evolutionary Novelties," in
Evolution after Darwin, vol. 1: The Evolution of Life, ed. Sol Tax, Chicago:
University of Chicago Press, 1960, pp. 349-380. 28 Mayr, for instance, repudiates what he calls "selectionist
extremism," and says that much of the phenotype is a by-product of the
evolutionary past, tolerated by natural selection but not necessarily
produced
under current conditions.... The mere fact of the vast reproductive surplus in
each generation, together with the genetic uniqueness of each individual in
sexually reproducing species, makes the importance of selection inescapable.
This conclusion, however, does not in the least exclude the probability that
random events also affect chances of survival and of the successful
reproduction of an individual. The modern theory thus permits the inclusion of
random events among the causes of evolutionary change. Such a pluralistic
approach is surely more realistic than any one-sided extremism" (TNPB, pp.
136,140). Still, he also wants to say that the modern synthesis for which he is
perhaps the leading spokesman "was a reaffirmation of the Darwinian
formulation that all adaptive evolutionary change is due to the directing force
of natural selection on abundantly available variation" (TNPB, p. 527;
emphasis mine). 29 See S. J. Gould and R. Lewontin, "The Spandrels of San
Marco and the Panglossian Paradigm: A Critique of the Adaptationist
Programme," Proc. Royal Society London, B205, 1979, 581-598. 30 0ne such problem is that a mutation affecting the phenotype
in a major way would require co-ordinated change in hundreds of genes; another
is that a macro-mutation in a single individual would not be enough, in a
sexually reproducing species, to establish a new kind right away. The role of
mutations in evolutionary change is much less dramatic than is often conveyed in
popular accounts; they serve mainly to augment the stock of variations in a
population upon which recombination can work. (Recombination is the blending of
fraternal and maternal DNA in each new biological individual in a sexually
reproducing species; it is responsible for the fact that each such individual is
different from all others.) 31 In the early stages of life's development on earth, sixty or
seventy different phyla (morphological types) developed, most of which became
extinct. Not a single new phylum has originated since the Cambrian period, more
than four hundred million years ago. It would seem that the genetic structures
of this early period were not as fixed as they later became. Selection may thus
have had fewer constraints then than later on when highly cohesive genotypes
developed; the rate of species-change might thus have been quite rapid, lowering
the chances of an adequate fossil record of the changes. 32 The differences between the "punctuated
equilibrium" model of Gould and Eldredge and the standard one of the modern
synthesis are not nearly as great as was originally claimed. In particular,
Gould's original assertion that only a "non-Darwinian" theory could
handle the evidence from the fossil record was quite clearly based on a very
narrow construal of what ought to count as "Darwinian." Mayr has to my
mind convincingly shown that Gould's own model is compatible with Darwinian
principles (TNPB, chapter 26). 33 Denton's comparison of the modern synthesis to late
Ptolemaic astronomy with its profusion of epicycles, and his conclusion that it
is a paradigm in crisis (Evolution, chapter 15) cannot, I think, be sustained.
The crucial disagreement between us would be as to what constitutes an ad hoc
modification (what he, oddly, calls a "tautology"). 34 "God fashioned man from the dust of the earth and
breathed into his nostrils the breath of life" (Genesis 2, 7). The "fashioning" here
could be that of a billion years of evolutionary preparation of that "dust" to form a being that for
the first time could freely affirm or freely deny his Maker. Pius XII in his encyclical Humani Generis
(1951) allowed that such an evolutionary origin of the human body was an acceptable
reading of the Genesis text. But he added that the human soul could not be so understood; it had
to be specially "infused" by God, presumably not just in the case of the first humans, but
all humans since. Many theologians today would find the Platonic-sounding dualism
underlying this assertion troubling. The uniqueness of God's covenant with men and women
and of the promise of resurrection does not require that there be a naturally
immortal soul, distinct in its genesis and history from its "attendant" body. But it is
unnecessary to develop this issue here, since Plantinga's challenge extends to the evolutionary account of
the plant and animal worlds, and not simply of the human.
36 The Literal Meaning of Genesis, 2 vols., translated by J. H. Taylor, New York: Newman, 1982, V, 23; p. 175 (Translation slightly modified.).
37 "Inevitable" is a word that defenders of evolution, whether theists or not, would be uneasy with. It suggests that the evolutionary process is at least in a general way deterministic or predictable. But this is just what nearly all theorists of evolution would deny.
38 There is one further perspective on this matter of
semi-deism that I have deliberately set aside above. The occasionalists of the fourteenth century maintained that God is the only cause, strictly speaking, of what happens in the world. What appears to be causal action within the world is for them no more than temporal succession. Things do not have natures that specify their actions; rather, the fact that they act according to certain norms must be directly attributed to God's intentions. There is no reason why God should not, for example, suddenly make new kinds of plants and animals appear, if He so wishes; since there is no order of nature, God is committed only to the reasonable stability of (more or less) regular succession on which human life depends. The issue that separated the nominalists from the Aristotelian defenders of real causation in nature is brought out very well in the essay by Alfred Freddoso cited by Plantinga: "Medieval Aristotelianism and the Case against Secondary Causation in Nature," in Divine and Human Action<
In this perspective, the issue of "special creation" comes to be posed in a quite different way. Any view which affirms the sufficiency of the natural order for bringing out the origins of life might be dubbed by the occasionalist as "semi-deist." When I read the paragraph in which Plantinga says that someone who maintains that God creates, conserves, and concurs in the activity of the universe is "semi-deistic," my first reaction was to assume that this committed him to occasionalism, since it is only from the occasionalist perspective that this view of God's relationship with the natural order would be classed as "semi-deist." But Plantinga is quite evidently not an occasionalist; his treatment of natural science implies that he believes in the operation of secondary causation in nature. Thus, I have assumed in the discussion above that Plantinga must have had something else in mind, namely, th
39Though the alert reader will have caught echoes of the
theology (not the biology; see section 5 above) of Teilhard de Chardin, the
affinities with the Christology of Karl Rahner are more immediate perhaps. See,
for example, his "Christology within an Evolutionary View of the
World," Theological Investigations, Baltimore: Helicon, vol. 5, pp. 157-191