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KRONOS Vol VIII, No. 3
THE SCIENCE OF EVOLUTION (PART I)
The frequency with which denigrators of Velikovsky are found in the ranks of vociferous evolutionists suggests the desirability of examining the current state of the art in the science of evolution. The journal Skeptical Inquirer is well known for its indiscriminate attacks on catastrophism and creationism. Less well known is the new little journal Creation/Evolution, founded by some of the very same skeptics for promotional purposes. The editorial statement introducing the first issue (Summer 1980) states that the journal is "dedicated to promoting evolutionary science".
That an established science needs unabashed "promoting" suggests that all is not well in that science whose centenary was celebrated with such fanfare in 1959. It gives one pause to learn in the pages of Creation/Evolution (Spring 1981) that professional scientific bodies feel obliged to issue evolutionary manifestoes and to organize committees of correspondence in defense of evolution. The editor, Frederick Edwords, informs us of such recent developments as:
What exactly is this "best scientific explanation of human and nonhuman biology"? In a previous article we examined Heribert Nilsson's scientific but non-evolutionary explanation (Gray 1982). In this article we will say nothing of creationism, but rather concentrate on the great range of evolutionary conceptions being currently offered by evolutionary scientists. Indeed, "range" is hardly an adequate designation for positions that are mutually contradictory.
To conceive of evolution as a science is, by and large, either to equate it with paleontology (the traditional way) or to equate it with genetics (the modern way). The widespread hostility now being directed by many evolutionists at the merely historical evidence embodied in the fossil record is treated elsewhere.(1) Inductive generalizations, based on an admittedly fragmentary sample from the past, can never result in a science comparable to physics and chemistry. Indeed, only physics and chemistry can be sciences in that sense. It is no wonder, then, that molecular genetics has come to the fore as a major candidate for the science of evolution.
The emphasis on genetics as the heart of the science of evolution is perhaps best examined in a recent book primarily devoted to genetics and actually entitled The Science of Evolution (1977). William Stansfield's book (which is published by Macmillan) is especially relevant to our purposes; not only does it come recommended by the experts, but also its treatment is strong at the two extremes of the subject and largely ignores the traditional middle ground. Evolution is treated there in terms of non-paleontological knowledge and the sociological context that gives rise to the public conflict over evolution (the two poles of his book). The recent public conflict in California over evolution taught as truth rather than hypothesis in the schools has made it expedient for this professor at California Polytechnic University to begin his advanced textbook with a sympathetic account of the Scopes trial and to conclude it with courteous gestures in the direction of anti-Darwinians Murray Eden (1967) and Norman Macbeth (1971)although neither is a biologist.
A sign of the times - an indication that the public is really listening when evolution is discussed and that scientists are now required to make at least token acknowledgement of the existence of basic criticisms of what they present as scientific orthodoxy - is the final eight pages of this 600-page book. Stansfield makes no attempt to answer the serious criticisms developed by Eden and Macbeth, but he does provide an objective summary of them. The problem with such a book (admirable though this one is for its relative open-mindedness) is that it is neither fish nor fowl - neither the elements of an unequivocal science nor a responsible presentation of a seriously contested scientific issue.
By calling his book The Science of Evolution instead of, say, The Science of Genetics, Stansfield greatly expands the potential market for his textbook but also greatly expands the legitimate scientific and social criticisms of it. And with this much of a foot in the door, those hostile to the teaching of biological evolution as a proven scientific theory at public expense are likely to be making their influence felt more strongly in future editions of such books. Stansfield does not acknowledge any pressure from the California State Board of Education, but he does discuss its 1969 guidelines on science teaching. What he does not even mention are the detailed attacks on Darwinism by European biologists.
Quite characteristic of the American tradition of evolutionary biology is its studied ignoring of European work when it runs counter to uniformitarianism and Darwinism. Before examining Stansfield's very American conception of the science of evolution, let us sample the sort of professional thinking on the subject that is filtered out for the protection of American students. Pierre Grassé's Evolution of Living Organisms (1977) is the counterpart treatment of the science of evolution.
Grassé was for many years professor of evolutionary biology at the Sorbonne, and he continues as the general editor of the monumental Traité de Zoologie, which is still going strong after dozens of volumes. Furthermore, he is a geneticist of importance in his own right. He serves as our representative of evolutionary tradition, which is "paleontology, the only true science of evolution" (p. 4). Nonetheless, the subtitle of his version of the science of evolution is Evidence for a New Theory of Transformation. Grassé is no conservative, no voice out of the past, no debunker of evolution, but he is certainly an outspoken critic of Darwinism and an outspoken advocate of the fundamentally historical nature of evolution. Grassé is shocked at the glib means by which professional consensus, especially in the Anglo-American world, has created a dogma out of what should be an open scientific question.
The European tradition of non-Darwinian biology includes not just the evolutionism of Grassé but also the anti-evolutionism of Nilsson (1953). However, both rely heavily on fossils as the record of unique events. In addition to conflicting conceptions of what constitutes the scientific study of evolution (for example, Grassé versus Stansfield) is a conception of the historical geological record so clearly and repeatedly catastrophic as to render improbable the continuity of highly developed life from era to era. The weakness of traditional catastrophism is the lack of a unified theory, but it never loses sight of the geological facts. As emphasized by another European, the leading historian of the battle between catastrophism and uniformitarianism: "Catastrophism held that interpretation ought to be adapted to geological facts; Uniformitarianism tended to interpret data in conformity with the assumption of the immutability in kind and degree of all geological causes" (Hooykaas 1970: 50). The battle is still far from decided, and the geological facts - mere empirical data from the past though they may be - are still the stumbling block to all uniformitarian assumptions.
A useful way to begin our analysis of paleontology as the science of evolution is to quote from a review of the original French edition of Grassé, L'Evolution du vivant (1973), written by a leading Darwinian - Theodosius Dobzhansky. First is Dobzhansky's concise and accurate characterization of the book and its purpose:
Then follows a judicious appraisal of the author's distinguished professional standing:
Lest this possibly be taken as damning with faint praise - as making Grassé out to be simply a walking encyclopedia full of interesting facts - we might add that Grassé is quite accustomed to putting himself on the line with bold hypotheses. Between the original edition and the English translation (1977), Grassé's prediction about overlapping genes was independently confirmed. This is another big step away from the particulate assumptions of classical Mendelian genetics, but it is also a big step away from the genetic "code" assumptions of what has come to be referred to as the "central dogma" of DNA genetics:
Piano keys are certainly a long way from the unmoved mover.(2)
Geneticist though he is, Grassé has never deviated from his oft stated conviction that paleontology is the only true science of evolution. In contrast to the science of evolution - of change - is the science of heredity - of preservation: "genetics is the science of 'heredity,' of the preservation of the specific gene pool; its relationships to evolution are known only through theories" (p. 5). Evolution is history, and history is much more a matter of empirical facts than of speculation. Grassé has a more flexible conception of how empirical data of fossils should be interpreted than does Nilsson, but he has a more exact conception than does "the English or American reader schooled in orthodox Darwinism" (p. x).
For Grassé, as for Nilsson, exact means that "Facts must come first and theories must follow" (p. 8). For these European holdouts against the Darwinian "myth", there is no need for a Popperian revival; the old-fashioned concept of fact is quite sufficient to reveal the falsity of what theoreticians lay down as established truth. Such a position is most naturally formulated in rhetorical-legalistic terms. Grassé stresses that
A court is no substitute for a laboratory for making scientific discoveries, but it is the natural setting for debates that seek to refute pseudoscientific claims championed from sectarian positions. And Grasse does call Darwinism a pseudoscience. Perhaps erroneous science is usually eliminated in the normal course of scientific experimentation without wide-open debate, but sometimes pseudoscience may take root in a field: "Through use and abuse of hidden postulates, of bold, often ill-founded extrapolations, a pseudoscience has been created. It is taking root in the very heart of biology ..." (p. 6).
If refutation is to play a central role in science, counter-arguments must be given their day in open court, but what all too often happens is that opposition is simply dismissed. The standard justification is that there is so much nonsense coming from the Yahoos and the lunatic fringe that "scientists would be paralyzed if they constantly had to question hypotheses that lie deeply embedded in the structure of their disciplines" (Nelkin 1977). This implies that fully certified experts in a discipline necessarily share the deeply embedded hypotheses and that these are so fundamental to the group psyche as to be almost myths. As far as evolutionary biology is concerned, all that is shared across the Atlantic is "myth" as a common accusation. To judge by what the experts say, the amount of myth in the field is overwhelming. And this is not just a conflict of Darwinism versus non-Darwinism.
On the one hand, Grasse is out "to destroy the myth of evolution" by strict recourse to paleontological data:
On the other hand, Darwinian cladists Niles Eldredge and Joel Cracraft claim that "the myth persists among paleontologists (and also quite a few of our neontological colleagues) that fossils somehow afford the best, if not the only, means of reconstructing phylogenetic history" (1979:1).
We cannot even attempt here to explain Willi Hennig's alleged cladistic revolution in evolutionary biology (which is anti-paleontological without being genetic). We simply note that according to Darwinian non-cladist Michael Ghiselin, who reviews the Eldredge and Cracraft collection as "an artfully biased sample of recent phylogenetic opinion" and as "an ideological document only intelligible in metascientific terms", "The contributors admit what everybody ought to know: that a great deal of what is said about science and its history is propaganda and myth. They fail to consider the implications of how they themselves might be managing the truth" (1981).
To dissociate Grassé somewhat from this mythological context, we might offer - as the best test of a commitment to truth - the classical Socratic acknowledgement of ignorance. At his best, this is what Karl Popper champions, and so does Grassé. "Science, which does not accept any credo, or in any case should not, acknowledges its ignorance ..." (p. 2).
By and large, Grassé is one of the best examples of evolutionary humility - of a frank admission by an expert on biological evolution of how little is actually known about the rise and fall of species. Yet paradoxically, Dobzhansky's basic criticism of him is that Grassé claims to know what is not known: "not even a biologist of Grassé's experience can judge reliably which 'characters' are useful, neutral, or harmful in a given species." This is a legitimate criticism, but it cuts both ways: against the deficiency of Darwinism as well as against the presumption of anti-Darwinism. Macbeth found the deficiency alarming: "If men of this caliber cannot tell whether a trait is beneficial, neutral, or deleterious, the situation is very disconcerting indeed" (1979). In claiming that he can indeed determine this, Grassé is also claiming that, notwithstanding the Darwinian requirement that no animal shall actively develop a harmful structure, some organisms do actively develop them. Grassé's explanation for this evolutionary phenomenon is the concept of "idiomorphon". Whatever this is, it is not chance. Dobzhansky's summary is quite to the point:
A central irony of evolutionary biology is that Darwinians argue for usefulness arising by chance and non-Darwinians argue for harm arising by design. Neither side can prove its case, so the result is a stalemate over burden of proof. On the one hand, when Grassé, the non-Darwinian, says that "It is absolutely impossible to see what role selection can have played in the acquisition of such unlikely characteristics" (p. 128), Dobzhansky counters that this negativism is not acceptable: "not even a biologist of Grassé's experience can judge reliably which 'characters' are useful." On the other hand, when Dobzhansky, the Darwinian, says that "Natural selection has no plan, no foresight, no intention", Grassé counters that this negativism is not acceptable: "To say that natural selection is not directed because you cannot see anyone or anything directing it is not an acceptable objection" (p. 128). Darwinian evolutionists force the burden of proof upon those who claim that the Irish elk developed harmful antlers to demonstrate that these were of no use. Non-Darwinian evolutionists force the burden of proof on those who claim that the Irish elk did not develop harmful antlers to demonstrate how the acquisition was useful.
Grassé thinks he knows why the Irish elk had such monstrously self-defeating antlers. They were the working out of a common pattern implicit in the various species of deer, the family Cervidae. According to him, species evolve in various parallel lineages directed by largely unknown laws, but laws whose manifestation in specific lineages is too obvious to be rationally denied. The central conflict in the biological realm is not, then, the competitive struggle between organisms but the struggle within an organism either to remain as it is and reproduce itself as such or to evolve in the general direction demanded of its line:
Biological evolution is, for Grassé, an historical "fact and not a hypothesis' (p. 3). What biologists mean when they refer to the fact of evolution is the obvious sequential order of development discerned in the rocks and less clearly discerned in embryos - that is, various manifestations of general patterns. But the theory of evolution is something else again, something requiring as a bare minimum precise knowledge of the mechanism, or principle, or rules whose operating explains the cause of the empirical patterns. But the difficulty of advancing beyond the empirical data to the rules that presumably are operating is almost insurmountable: "We rarely discover these rules because they are highly complex; they are not easily expressed in mathematical terms because the number of parameters they involve is so great" (p. 2). Thanks to the fossil record, we can see that "biological evolution never ceased proceeding from the simple to the complex along definite lines" (p. 11). Increasing growth, complexity, and intelligence ("psychism") is in general much more in accord with the evidence from the past than is chance variation leading to enhanced ad hoc adaptation. And on this basis, we can formulate, abstract, typify and finally classify - these lines. Biological evolution is an historical, irreversible, goal-oriented progression that operates at any given time with whole suites of integrated characters:
Idiomorphons can be discerned at every level from genus to phylum, but phyla are the heart of the matter: "The formation of the phyla, or basic structural plans, constitutes the most important and, perhaps, the essential part of evolution. Each phylum offers great novelties and its structural plan guides the destiny of the secondary lines" (p. 27).
Although Grassé is thoroughly convinced of the monogenesis of life - "biogenesis did not repeat itself" (p. 90) - he admits that the origins of individual phyla are unknown and probably unknowable:
Monogenesis plays no significant part in Grassé's conception of evolution except to emphasize the historical nature of it. Paradoxically, Grassé slights historical evidence for repeated biogenesis in the past as part of his effort to demonstrate historicity. However, it is one thing to say that "The historicity of biological evolution is proved by the present complete interruption of all forms of spontaneous generation of living beings from inert materials" (p. 89). It is quite another thing to say that "Spontaneous generation occurred once and only once" (p. 88).
So important to Grassé's conception are the various Idiomorphons, one is tempted to say that separate origin at least at the level of phyla and perhaps also at the level of classes would serve him much better. Yet despite quite candid admissions - "There is no evidence of a continuity between unicellular algae and multicellular algae" (p. 2), "In spite of extensive study, the origin of the Metazoa is still unknown" (p. 13), "paleontology does not shed any light on the genesis of the phyla" (p. 27) - Grassé insists that "In the current status of biology everything supports the idea that the transformation of the schizophyte into a cell took place only once and that all existing uni- and multicellular creatures are products of it. The historicity of evolution is affirmed by the fact of a unique 'creation' ..." (p. 179).
What exactly this "everything" is, Grassé does not explain; what he does provide definitely undermines monogenesis. Take, for example, the mammals. Unlike cladistic taxonomists, Grassé is not committed to a strict phylogenetic classification. Thus he can readily acknowledge the evidence for polyphyly of the class Mammalia. However, Grassé is at best inconsistent about what he means by polyphyly. As one committed in theory to a single origin of all life, Grassé should be referring only to the taxonomic realm. But when he repeatedly speaks of the "genesis" and "creation" of individual phyla and classes, polyphyly would have to refer to the phylogenetic realm. In one way or another, Grassé is also a creationist - a much more guarded one than Nilsson - but definitely a believer in multiple origins that are inexplicable in phylogenetic terms:
What defines a higher taxonomic group (class, subphylum, phylum) cannot be common origin, because this is not known. It is rather an idiomorphon - an abstraction, an essence. There seem to be only a limited number of viable possibilities for biological complexity, and these seem to have been exhausted long ago. After the origin of the mammal and bird Idiomorphons, the "heyday" of evolution was over: "no broad organizational plan has appeared for several hundred million years, and for an equally long time numerous species, animal as well as plant, have ceased evolving" (p. 84).
This is a convincing reason for emphasizing that evolution is fundamentally historical, that there can be no general law such as natural selection. Year in and year out over the millennia there is no one evolutionary process constantly at work doing by and large today what it was doing several hundred million years ago. The biological present is not the key to the evolutionary past in any lawful sense. There was no heyday of gravitation, but there was a heyday of creative evolution: "Creative stages ended long ago, except in birds and mammals, which became individualized at the beginning of the Tertiary and specialized during that era. Now their evolution is also confined to speciation" (p. 82).
Mammals are probably not monogenetic, according to Grassé, but whether they are or not has little bearing on his conception of oriented evolution. Orientation is a matter of final causes as well as of physical causes - of what proves to be a viable end product as well as what unknown archaic stock provided the generalized gene pool:
This is definitely Aristotelian, and Grassé does not disavow the tradition. About all that he does disavow is the term orthogenesis.
When George Gaylord Simpson describes the evolution of horses in terms of steadily increasing size and specialization through thousands of generations, his vigorous denial of orthogenesis does not prevent his critics from claiming orthogenesis or Grassé from citing this approvingly as an example of an idiomorphon. Grassé must, on the one hand, criticize Darwinians' rejection of oriented evolution, which they do as orthogenesis. He must, on the other hand, praise the evolutionary studies done by Darwinians when they seem to demonstrate large trends not explicable in terms of ad hoc natural selection. Not just the evolution of horses but also the parallel evolution of new and old world horses is a case in point:
The horses are not a conspicuous example of an idiomorphon relentlessly developing toward extinction, but there are plenty of these from molluscs that finally sealed themselves into their shells to dinosaurs that outgrew their environment. The antlers of the Irish elk are a very minor manifestation of a seemingly widespread kind of problem:
Grassé is something of a catastrophist, but wherever possible he sees extinction not as evidence of external causes but of internal causes. In this respect, he is the opposite of Nilsson, who did not recognize the evolution of long lines of species and thus could not accept relentless over-development culminating in a monstrous descendent that sometimes literally collapsed under its own weight.
Oriented evolution, whether heading for success or failure, is the positive side of Grassé's case. The negative side he shares with Nilsson - the failure of experimental biology to demonstrate the accumulation of micro mutations into new macro groups capable of surviving in nature: "The fruitfly (Drosophila melanogaster), the favorite pet insect of the geneticists, whose geographical, biotopical, urban, and rural genotypes are now known inside and out, seems not to have changed since the remotest times" (p. 130). It was no surprise that Dobzhansky was given the opportunity to review Grassé's book, because Grassé (like Nilsson) specifically attacks Dobzhansky and his fruitflies. For these two anti-Darwinians, mutations are not evidence for evolution but evidence against it:
Reviews of books by opponents are quite common and usually quite irresponsible. Dobzhansky has been more judicious here than most. But he is out to blur Grassé's case against classical genetics and the neo-Darwinian synthesis. Central to Grasse's case is his oft repeated assertion that "The entire evolutionary process has nothing to do with mutations" (p. 42). Yet according to Dobzhansky, "Grassé says that the occurrence of mutations does not necessarily result in evolution."
Grassé's "New Theory of Transformation" requires this either/or stand; otherwise it will be sucked into the vague neo-Darwinian synthesis and lost. What this theory is can be better explained after we examine Stansfield's genetic conception, which is orthodoxly neo-Darwinian.
... to be continued.
1. In my forthcoming Evolution and the Revolution that Failed: The Semiotics of Taxonomy, from which the present article is largely taken.
2. For a semiotic analysis of the metaphoric superstructure of the latest "revolution" in biology - "deciphering the genetic code", "understanding the language of the cell" see Gray 1981.