(revised May 17, 1997)
Charles Darwin's classic, On the Origin of Species by Means of Natural Selection, was a persuasive and compelling argument for the idea that minor evolutionary change could be extrapolated to account for the origin of the all of the major forms of life by purely mechanistic and materialistic processes. Writing on the origin and impact of evolutionary thought, Douglas Futuyma put it this way:
Darwin showed that material causes are a sufficient explanation not only for physical phenomena, as Descartes and Newton had shown, but also for biological phenomena with all their seeming evidence of design and purpose. By coupling undirected, purposeless variation to the blind, uncaring process of natural selection, Darwin made theological or spiritual explanations of the life processes superfluous. Together with Marx's materialistic theory of history and society and Freud's attribution of human behavior to influences over which we have little control, Darwin's theory of evolution was a crucial plank in the platform of mechanism and materialism --- of much of science, in short --- that has since been the stage of most Western thought (Futuyma 1986).
Were Darwin's extrapolations justified? Judging from the conclusions of many of the scientists attending one of the most important conferences in evolutionary biology in the past forty years, the answer is probably not.
The central question of the Chicago conference was whether the mechanisms underlying microevolution can be extrapolated to explain the phenomena of macroevolution. At the risk of doing violence to the positions of some of the people at the meeting, the answer can be given as a clear, No (Lewin 1980).
Lewin's article on the conference in the AAAS journal, Science, described some of the major conflicts between the modern neo-Darwinian theory of evolution and the empirical evidence:
Evolution, according to the Modern Synthesis, moves at a stately pace, with small changes accumulating over periods of many millions of years yielding a long heritage of steadily advancing lineages as revealed in the fossil record. However, the problem is that according to most paleontologists the principle feature of individual species within the fossil record is stasis, not change...
In a generous admission Francisco Ayala, a major figure in propounding the Modern Synthesis in the United States, said "We would not have predicted stasis from population genetics, but I am now convinced from what the paleontologists say that small changes do not accumulate" (Lewin 1980).
If small changes do not accumulate, if stasis is the principle feature of individual species in the natural history of life, if natural selection inhibits or precludes major evolutionary change, if the order of appearance in the geologic record is systematically backwards to Darwinian predictions, and if the higher taxa are as discontinuous as they appear to be, why is it that scientists don't develop theories to explain the natural limits to biological change? The answer seems to be more philosophical than empirical. Although the question would probably lead to a more accurate description of nature, it would undoubtedly undermine the pervasive secular philosophy of mechanism and materialism which has come to dominate modern science. Although the question could certainly lead to fruitful scientific research, the thought that natural processes might actually prevent major evolutionary change from occurring would be anathema to those scientists who hold to some form of philosophical naturalism or secular religion.
In a recent AAAS conference Michael Ruse, philosopher of science and noted defender of Darwinism, admitted that evolutionary theory is clearly based upon metaphysical assumptions.
"And certainly, there's no doubt about it, that in the past, and I think also in the present, for many evolutionists, evolution has functioned as something with elements which are, let us say, akin to being a secular religion ... And it seems to me very clear that at some very basic level, evolution as a scientific theory makes a commitment to a kind of naturalism, namely, that at some level one is going to exclude miracles and these sorts of things come what may." (Ruse 1993)
In other words, no matter what the evidence infers, no matter how inadequate Darwinian theory might be, only naturalistic explanations to questions of origins will be considered scientific.
If we assume science to be limited to the study of purely materialistic processes and we further assume that the origin of life and the origin of the major body plans are subject to scientific investigation, then the only truly scientific explanation of origins must be materialistic and naturalistic by definition. Under these rules of reasoning some form of Darwinism is the only possible "scientific" explanation of origins. Creation in any form, including theistic evolution, is by definition "unscientific."
Such reasoning is reflected in a booklet published by the National Academy of Sciences entitled Science and Creationism (1984). The influential National Academy of Sciences, representing the nation's most notable scientists, has argued that the concept of creation is not scientific:
...it fails to display the most basic characteristic of science: reliance upon naturalistic explanations. Instead, proponents of "creation-science" hold that the creation of the universe, the earth, living things, and man was accomplished through supernatural means inaccessible to human understanding (National Academy of Sciences, 1984).
The National Academy of Sciences simply defined away all alternatives to purely naturalistic evolution by insisting that only naturalistic explanations can be considered in answering questions of ultimate origins. By definition there is no scientific alternative to the idea that "man is the result of a purposeless and natural process that did not have him in mind" (Simpson, 1967).
Proponents of "creation-science" or advocates of "intelligent design" have never pretended to explain the mechanism by which the universe, the earth, living things, or man came into existence. For the most part, they have attempted to critique evolutionary theory and to point out areas of the theory which are either untestable or in conflict with empirical data. In so doing, they have inferred that purely mechanistic processes are insufficient to account for the order and complexity of the cosmos. This has provoked an almost religious reaction from the Academy:
"Creation-science" is thus manifestly a device designed to dilute the persuasiveness of the theory of evolution. The dualistic mode of analysis and the negative argumentation employed to accomplish this dilution is, moreover, antithetical to the scientific method (National Academy of Sciences, 1984).
Berkeley law professor, Phillip E. Johnson, in his book, Darwin On Trial, concludes:
The Academy thus defined "science" in such a way that advocates of supernatural creation may neither argue for their own position nor dispute the claims of the scientific establishment. That may be one way to win an argument, but it is not satisfying to anyone who thinks it possible that God really did have something to do with creating mankind, or that some of the claims that scientists make under the heading of "evolution" may be false (Johnson, 1991).
Must scientists and science educators continue to operate under the assumption that God had nothing to do with the origin and diversity of life on earth? Despite the fact that all other explanations of origins fail to meet the Academy's definition of science, the answer can be given as a clear, No. It is clearly beyond the realm of science to make such a religious assumption. Science must remain agnostic on the matter. God may have created or God may not have created. If He created, then the cosmos may exhibit an evolutionary or developmental continuity. It may just as well exhibit natural discontinuities. If He did not create, then the cosmos must exhibit an evolutionary or developmental continuity.
What is so ironic is that a theistic worldview is open to a wider range of empirical and historical possibilities than an atheistic worldview is. If theism can accommodate a continuous cosmos but atheism cannot tolerate a discontinuous one, then why would any scientist begin with atheistic assumptions? It is obviously far better to assume that God did create and ask how to best model the creation than it is to assume that He played no role whatsoever in the history of life on Earth. At the very least, all scientists need to be honest agnostics. The bottom line is the same. Scientists need to be open to the empirical possibility that nature is fundamentally discontinuous.
Philosophical naturalism requires that nature be fully continuous. The history of life must be represented by a tree. All life must have a common ancestor. All genetic change must ultimately be the result of purely unguided, materialistic processes. Theism, on the other hand, is much less restraining. Life may be either continuous or discontinuous. It follows that life may be modeled as a either a tree or a forest. (It should be noted that a forest of life accommodates continuity among the lower taxa and discontinuity among the higher taxa.)
Under a theistic or agnostic worldview it is incumbent upon the scientist to actually do more science. It is not sufficient to simply assume common ancestry. Scientific tests must be developed which may reject the hypothesis of common ancestry for the higher taxa and instead reveal the presence of natural discontinuities. The hypothesis of a random origin of genetic information must also be put to the test. The origin of 40-50 phyla within the five to ten million year window of the Cambrian explosion, for example, must be shown to be mathematically and biologically plausible if chance is to be invoked as the designer. If nature is discontinuous then there may even be natural processes which inhibit major evolutionary change from occurring and which explain the pervasive patterns of natural history and higher taxon-level stasis.
Although Michael Denton believes nature to be continuous, his account of the transformation of the scientific community from a discontinuous model of nature to a continuous one after 1859 is well worth reviewing. Whether nature turns out to be continuous or discontinuous is not the point. The point is that a discontinuous model is no less scientific than a continuous one. The ultimate question is which model most accurately represents the data?
Biology in the early decades of the nineteeth century was dominated by the idea that the organic world was a fundamentally discontinuous system in which all the major groups of organisms were unique and isolated and unlinked by transitional forms. ... Where there was variation, it was only trivial variation within the clearly defined limits of the species or type. Thus to the naturalists of the nineteenth century the basic order of nature was static and discontinuous, very different from the dynamic continuous model which was later to become axiomatic for most biologists after 1859. (Denton, 1985, p. 18)
Before 1859 it was fashionable and intellectually respectable to view the organic world as a discontinuous system. -- the result of successive creation interventions in the history of the world. After 1859 it became intellectually respectable to view life as the natural product of purely natural processes operating over long periods of time. Changing one's interpretation of the world is not, however, the same as establishing a new fact. The facts were the same in 1850 as they were in 1870, only the perception of them had changed. (Denton, 1985, p. 73)
The so-called typological model of nature adhered to by biologists early in the (19th) century was not without a considerable degree of empirical support. ... [T]he work of the great nineteenth century comparative anatomists such as Cuvier and, later, Owen had shown that the living world could be considered divided into distinct types or phyla and that organisms clearly intermediate between different classes were virtually unknown.
Comparative anatomy had also revealed that organisms were integrated wholes in which all the components were coadapted to function together; and this seemed to many to preclude any sort of major evolutionary transformation. As William Coleman, an authority on Georges Cuvier, points out:
The organism, being a functionally integrated whole each part of which stood in close relation to every other part, could not, under pain of almost immediate extinction, depart significantly from the norms established for the species by the first anatomical rule.
A major change, for example, a sharp increase in the heart beat or the diminution by half of the kidney and thus a reduction in renal secretion, would by itself have wrought havoc with the general constitution of the animal. In order that an animal might persist after a change of this magnitude it would be necessry that the other organs of the body be also proportionally modified. In other words, an organism must change en bloc or not at all. Only saltatory modification could occur, and this idea was to Cuvier, as it is to most modern zoologists, but for very different reasons, unverified and basically absurd. Transmutation by the accumulation of alterations, great or small, would thus be impossible.
Coleman, W. (1964)
Georges Cuvier: Zoologist
Harvard University Press
Cambridge, Mass, pp 172-73(Denton, 1985, p. 18)
When the appeal of the scientific paradigm and the natural desire of the scientific community to extend the range of scientific explanation are taken in conjunction with all the various intellectual trends and fashions of the later Victorian era, it is in retrospect perfectly easy to understand how Darwin's theory proved irresistible even though, as Darwin himself admitted, the actual empirical evidence was insufficient, and there was absolutely no evidence that any of the major divisions of nature had been crossed in a gradual manner. If nature was to be explained by natural processes, she had to be continuous. (Denton, 1985, p. 73)
As the years passed after the Darwinian revolution, and as evolution became more and more consolidated into dogma, the gestalt of continuity imposed itself on every facet of biology. The discontinuities of nature could no longer be perceived. (Denton, 1985, p. 74)
Given the morphological discontinuities among the higher taxa, the discontinuous appearance of the phyla in the Cambrian explosion, the reverse order of geological succession, the examples of irreducible complexity found at the molecular level of life (Behe, 1996), and the problem of homoplasy (functional or developmental homologies that cannot easily be explained by common descent) it is incumbent upon scientists to revise a pre-Darwinian model of nature, incorporating neo-Darwinian microevolution, speciation, punctuated equilibria, and other mechanisms which can account for the continuity and diversity of the lower taxa.
Beyond that, scientists will need to gain a much greater understanding of the processes underlying stasis. Species stasis commonly continues for millions of years, periods of time for which environmental constancy does not seem possible. Indeed, species stasis often appears to persist despite evidence for environmental change. Natural selection is obviously only a part of the whole picture. Internal genetic and developmental mechanisms may play an even greater role in maintaining higher taxon-level stasis by inhibiting transitional forms from developing in the first place.
If Mivart was correct in concluding that natural selection is incompetent to account for the incipient stages of useful structures, we can only criticize him for not taking his idea far enough. He could have developed a theory of "macrostasis" and established natural selection as a key mechanism underlying the phenomenon of morphological stability and the mechanism which explains the lack of transitional forms in the fossil record. Had he done so, we might have emerged from the nineteenth century with two major theories of biological change: one accounting for minor evolutionary change and the common ancestry of the lower taxa and another accounting for the stability of the higher taxa. More importantly, we would have entered the twentieth century with theories which more accurately reflected the empirical data.
As we enter the twenty-first century we should pause and re-examine our presuppositions as well as our data. We must be careful not to slip into scientism and must constantly strive to most accurately describe nature even if it means discarding some of our most cherished beliefs. As Pierre-Paul Grasse', past President of the French Academie des Sciences and editor of the 35 volume Traite' de Zoologie, expressed it:
Today our duty is to destroy the myth of evolution, considered as a simple, understood, and explained phenomenon which keeps rapidly unfolding before us. Biologists must be encouraged to think about the weaknesses and extrapolations that theoreticians put forward or lay down as established truths. The deceit is sometimes unconscious, but not always, since some people, owing to their sectarianism, purposely overlook reality and refuse to acknowledge the inadequacies and falsity of their beliefs (Grasse, 1977).
We must bear in mind that just because neo-Darwinian evolution is the most plausible naturalistic explanation of origins, we should not assume that it is necessarily true. Likewise, just because creation involves processes which are non-natural, we should not assume that creation events -- whether sudden or gradual -- have not occurred. It would be unreasonable to assume so. Nature may turn out to be discontinuous after all. Creation events may not be subject to scientific investigation, but stasis most definitely is. "Stasis is data."
In retrospect, it seems as though Darwinists have been less concerned with the scientific question of accurately explaining the empirical data of natural history and more concerned with the religious or philosophical question of explaining the design found in nature without a designer. Darwin's general theory of evolution may, in the final analysis, be little more than an unwarranted extrapolation from microevolution based more upon philosophy than fact. The problem is that Darwinism continues to distort natural science.
If it turns out that natural selection plays a more dominant role in the phenomenon of higher taxon-level stasis than it does in major evolutionary change, the irony will be that Darwin himself may have predicted this opposite conclusion over 130 years ago.
"I am well aware that there is scarcely a single point discussed in this volume on which facts cannot be adduced, often apparently leading to conclusions directly opposite to those at which I have arrived. A fair result could be obtained only by fully stating and balancing the facts on both sides of each question, and this cannot possibly be done here." (Charles Darwin,The Origin of Species, 1859)