I should start by saying that I haven't read this book. However, I have collected many reviews by others. As "editor", I will comment that the reviews by scientists have all painted about the same picture, and they are all consistent with the discussions I've seen on Usenet's "talk.origins".
Net postings gathered onto this web page:
My understanding is that Denton's subsequent book retracts the idea that there are multiple trees of life. He now agrees with science that there was common descent with modification, via natural processes. Because of this understanding, and because of the reviews listed above, I do not plan to read "A Theory In Crisis".
The main weakness I recall was a confusion between actual lines of descent and the modern representatives of the stages along these lines. This was most obvious in his discussion of cytochrome-c analysis. He declared that evolution predicted that ( say ) fish, frogs, and birds should have successively less correlation with a common ancestor in their amino acid sequences.
This is not found, of course, since all these modern animals have been diverging for the same length of time from any common ancestor. Evolution predicts a hierarchy of groups, each of which is defined by a constant correlation with that group's common ancestor, and with the smaller more recently evolved subgroups having a higher correlation with their more recent common ancestor. The data fits this expectation very well, and this fit is rightly regarded as a brilliant confirmation of the phylogenies based on morphology.
So if an author gets something THIS fundamental THAT wrong, where does that leave him? Out in left field, I say. Nevertheless, the book is coherent enough to make for some stimulating reading. That is, it may be challenging to discover the errors of argument in each case, but be aware of the author's predilection for unsound argument. I actually saw Denton's cytochrome-c argument repeated by a creationist ( Richard Bliss ) before I saw Denton's book. I reported this on the net several years ago.
Another interesting, but spurious, argument is based on homologies of structures in the same organism. Denton states that hands obviously can not be evolved from feet, or vice versa, so that their similarities cannot be explained by descent with modification. Of course, a little consideration of the importance of segmentation in the development of individual organisms reveals the bankruptcy of this argument.
I came across the following letter in the December 1989 issue of Perspectives on Science and Christian Faith (The American Scientific Affiliation's Journal):
"I am writing in response to the recent (December 1988) and lengthy review of Michael Denton's "Evolution: A theory in crisis". The reviewer, (T.E. Woodward) presented a very favorable account of a book whose claims to scholarship or integrity are woefully deficient. The book is praised as "an intellectual and spiritual delight," a forceful critique," and a "careful historical review." Furthermore, the impression is given that informed reviews likewise share the same positive appraisal. I take serious objection to all these points.To start in reverse order, five out of seven reviews I could obtain in my university library pointed out the serious errors of logic, synedoches, direct misquotes, gross factual mistakes, and even spelling errors in Denton's book. The only slightly positive comments came from the "Parabola" - an eastern mysticism journal - and from Stephen Rose who approved the critique of the path of avian evolution of flight even though he acknowledged the serious errors and oversimplifications in the book.
Why are all these reviewers so irate? Basically, the same old creationist tactics and ill-founded objections. Consider Denton's facile explanation of why evolution - the object of critique is macroevolution - is accepted by the scientific community: the "priority paradigm." This Kuhnian notion (already problematic in Kuhn's own work) is given the sole task of founding Denton's portrayal of a theory in "crisis" which is nevertheless not abandoned.
Denton's lack of precision - he conflates natural selection with chance - and expertise is also evident in his treatment of technical disputes within biology. These include the punctuationalists' attempts to decouple macroevolution from microevolution, the cladist attack on Darwinian phylogenies, Kimura's neutralism and discussions of the paths of evolution (such as avian flight). The standard creationist tactic consists of "research by exegesis" or eisogesis in this case; quotations from opponents in some minor technical dispute are judiciously chosen to make both positions seem untenable leaving agnosticism or creationism the only remaining alternatives. Denton's mishandling of these technical disputes enables him to conclude that there is no reason to believe that evolution of the higher taxa ever occurred.
Denton unearths the typological perception of nature which was legitimately abandoned due to its lack of explanatory power. Denton proposes that all mammals are derived from a mammalian "archetype", fish from a fish archetype and so on. But how many archetypes will Denton need to account for the incredible diversity past and present species? Secondly how are these species "derived" and what are the limits to change since he allows for microevolution? Thirdly, how can this anachronistic typology account for the examples of species which are not rationally explainable in terms of types and constitute powerful evidence for the fact that evolution has occurred? Thus, whales with femurs, Archaebacteria, strange animals on Madagascar, marsupials, toothed birds, ..are either ignored or dismissed by some sleight of hand - see Denton's treatment of Archaeopteryx. The whole discontinuous/continuous argument of Denton founders on his lack of precision and his failing to take into account significant research on the transitions between species or "types".
Perhaps the best example of Denton's lack of intellectual acuity can be seen in his mishandling of molecular homologies. He confuses cousin-cousin relationships with ancestor-descendant relationships and comes up with the profound conclusion that both fish and humans are "equidistant" from lamprey. From the gross differences that both fish and mammals have from lamprey he fallaciously concludes that all vertebrate groups are equidistant from one another. The remarkable agreement of molecular data with traditional evolutionary phylogenies beggars description. There is no reason why humans need to be more closely related to chimpanzees than most other species of primates. Ironically, even Denton's diagrams of nested sets point to the hierarchical nature of taxonomy (already derived from paleontology and comparative anatomy) which is yet another line of evidence for the fact of evolution.
Denton's major flaws lie in his scholarship and integrity. Firstly, his citations of leading biologists often distort and twist their intent (his discussion on taxonomy where he makes Halstead sound like a cladist!) Secondly he ignores arguments which he cannot criticize. Thus, key evidences for the fact of biological oddities and "imperfections," some of the better fossil transitions, comparative anatomy, biogeography, and the remarkable congruence of the geologic column with evolutionary hypotheses are not even addressed.
On a personal note, I must confess to the surface persuasiveness of Denton's book. The selective treatment of evolutionary biology - focused on difficult transitions and especially abiogenesis - and the impressive if fraudulent citations belie the true nature of the book's argument. On a second and more perspicacious reading I was at first disappointed and then finally infuriated by the unsustainable attacks on evolution and the even more repulsive misuse of sources. Denton rightly belongs with other misbegotten attacks on evolution such as Ian Taylor's "In the minds of men" - their popularity is inversely proportional to the biological or historical knowledge of their readers. Unfortunately the desire to see evolution refuted often grants evolution's critics a prior claim to truth. If we should go about refuting evolution it will require sound arguments and careful scholarship; nothing less is worthy of the evangelical community.
Marvin Keuhn
48 Carling Street #1
Hamilton, Ontario L8S 1M9
Canada"
<A previous poster> said:
"According to the typological model of nature all the variation exhibited by the individual members of a particular class was merely a variation on an underlying theme or design which was fundamentally invariant or immutable" (Denton, 1985, p. 94). It is a modern resurrection of the typological perception of nature that Michael Denton seeks to advance in his book, Evolution: A Theory in Crisis. Denton charges that, while microevolution and speciation have been proven beyond a shadow of a doubt, an examination of the biological (and paleontological) data and of the nature of evolutionary mechanisms reveals that the common evolutionary descent of all lifeforms is "a highly speculative hypothesis..."
My fundamental problem with the typological model of Denton is that he must at least try to define exactly what features of "theme or design" are "fundamentally invariant or immutable". This is particularly true since he allows substantial variation within these boundaries (enough to accommodate all the breeds of dogs as well as all Brassica species). So what features of theme or design represent immutable boundaries throughout the fossil record? Not size. Not morphology. Not development. Even a good example of where to draw the impossible-to-cross boundary in, say, the lineage of hominids or equines would help, so it could be consistently applied in the case of marine mollusks. Is eohippus a horse or not? If not, why not? Is H. erectus a human or not? If not, why not? Why are these fossils found in older sediments than the modern horse? Human? How does his typological model deal with change over time as indicated by the fossil record? Is he implying multiple creations and extinctions of "themes or designs" so that, for example, H. erectus can be grouped with its immediate ancestor (H. habilis) but excluded from being grouped with its more recent cousin (H. sapiens) because the former is not a "fundamental" variation whereas the later is? What would those "fundamentally invariant or immutable themes or designs" be? It's not just a question of fuzzy lines. There are no criteria for drawing the lines other than wherever one wants in Denton's typology. That is not exactly a solid grounding for structuring the biological world.
William Harvey's book entitled "De Motu Cordis et Sanguinis in Animalibus" was published in 1628. It established beyond reasonable doubt that the blood circulates, and it overthrew the ancient physiology of Galen. So compelling were Harvey's arguments that his conclusions became the consensus among the learned community within his own lifetime, even though the passage of the blood through the capillaries had yet to be seen.
Charles Darwin's book entitled "On The Origin of Species by Means of Natural Selection" was published in 1859. It established beyond reasonable doubt that organisms of different species are united by common descent, and overthrew the traditional view that they had come into being through supernatural acts. So compelling were Darwin's arguments that the evolutionary conception of the living world became the consensus among the learned community within ten years, even though the sort of fossil record that would have been all the more convincing was not yet available.
Harvey's idea that the heart is a pump and provides the main driving force behind the circulation remains a fundamental principle in cardiac physiology. So too with Darwin's principle of selection, without which so much of biology would be utterly unintelligible. Indeed, we owe much of our present understanding of the heart and blood to the fact that anatomists and physiologists know that such things evolve.
All this is common knowledge, or at least it ought to be. No properly educated person would entrust his own life, or that of his child, to a physician who did not know that the blood circulates and why it does. If a medical practitioner claimed that the blood does not circulate his intellectual credentials and professional integrity would be questioned. So we would look very carefully at his claims, admitting perhaps that all sorts of things are possible and we would not pre-judge the issues. If we found that his premise were false and his logic formally invalid, we would consider him discredited; and if we found him marketing such notions to a gullible public we would denounce him as a quack.
The same applies to scientific matters in general, including those from which modern cardiac physiology derives its legitimacy. If somebody said that the circulation of the blood is "just a theory, not a fact," we would take it as an insult to our intelligence. That the blood circulates is a fact, in the sense that the blood does in truth circulate. The theory presented in Harvey's book makes the structure of the blood intelligible in the light of the fact that the blood circulates. By the same token there is no contradiction in speaking of evolutionary theory on the one hand, and the fact that evolution has occurred on the other. One does not have to be a professional logician, or to know the technical term for it in formal logic to recognize such a flagrant instance of the fallacy of false disjunction. But the general public, having little acquaintance with theories anyway, is apt to be misled if such matters are not clearly explained in terms they can understand. And fallacious reasoning can be subtle. Logical fallacy becomes all the more pernicious when coupled with false premises of the sort that only an expert can identify as such.
A book by an author who is obviously incompetent, dishonest, or both -- and it may be very hard to decide which is the case -- ordinarily is not worth the attention of a professional scholar. If, however, the deficiencies are not apt to be recognized by the audience to whom a work is addressed, warning potential readers might be a valuable service. And discussing some examples of fallacious and false premises can sometimes be a useful exercise.
Michael Denton attempts to convince his readers that something is wrong with evolutionary biology. This he does primarily by attempting to resurrect one of the positions that evolutionary biology rendered untenable in the first place, namely the typological interpretation of biological classification systems (or taxonomy). A typologist would have us believe that organisms exist in nature as members of discrete classes, in the sense that everything clearly falls under one head or another. Hence each and every group can be rigidly defined, and there can be no overlap or intermediates between them. If this be so, then it would appear that either the groups in question have not evolved, or that if they have evolved, they have done so by large and discontinuous steps -- by "saltation." Because the current version of evolutionary theory rejects genuine saltations, there would seem to be something problematic about it.
Contemporary philosophy of taxonomy has a ready answer to Denton's argument. The groups, or taxa as they are called, are not classes in Denton's sense at all. They are lineages, or branches of genealogical trees. Therefore we should not expect to "define" them at all, in the sense that an organism simply must have a given property to occupy some position on a tree. The mischief comes from efforts to translate the branching diagram into a hierarchical arrangements of groups within groups.
Denton claims that organisms always possess the diagnostic features that purportedly "define" each group. If he understands why this is so, he does not tell his readers. Of course, if you go out in the wild, and find an animal with hair, you can be reasonably sure that it is a mammal -- though perhaps you might have trouble, say, with the "hair" on a tarantula. Why should this be? For the simple reason that whenever taxonomists find a group, they go through a great deal of material, looking for characters that happen to be present in all specimens of the group. These they treat as diagnostic -- which means that they are useful in identification, like the symptoms in a doctor's diagnosis of an illness. If they later find a specimen that belongs to the group, but does not have the diagnostic feature, they decide that the feature is not diagnostic after all, and perhaps look for other ones. The whole argument is circular, as Darwin clearly explained in 1859.
By the same token, Denton tells us that as a rule taxonomic groups are separated from one another by gaps, with few intermediates between them. Of course. One traditional practice among taxonomists has been to delimit groups at precisely those places where the gaps , for whatever reason, occur. They sometimes get filled in, as when expeditions are sent to previously unexplored areas, and the gaps get de-emphasized in the new systems of classification.
Denton alleges that few if any intermediates have been found between taxonomic groups. But he gerrymanders the evidence so as to rule out the kind of intermediate that most of us would consider a decent example. Consider the following diagram, which represents a genealogy among objects denoted by letters:
E D C
\ \ /
\ \ /
\ B
\ /
\ /
A
|
|
According to one not unreasonable usage, the lineage BD is "intermediate" between AE and C. So D in a sense would fall between E and C. (Invertebrate chordates such as sea-squirts and Amphioxus, which have notochords but not vertebrae, would thus be intermediate between vertebrates and other invertebrates.) Of course, E, D, and C do not represent a direct, ancestor-descendant relationship. A, B, and C do, and this is the only sense of an intermediate that Denton will accept. When dealing with extant creatures, we would only expect a certain amount of change to have occurred between, say, B and D. Furthermore, if we found a fossil specimen of B, we might have trouble deciding whether it really was a specimen of B, in the sense of occupying the exact point of bifurcation, or whether it was located along AB or BC, or perhaps some minor branch not shown on the diagram. Furthermore, if we look at a fossil such as B, we find that it has some properties present in C and D, but not in A -- Archaeopteryx, as close an intermediate as one could wish between birds and dinosaurs, is a good example. But all this is precisely what we would expect, given the fact that the objects are united by descent with modification.
So these arguments turn out to be flagrant instances of the fallacy of irrelevant conclusion: they do not bear upon the question of whether we have been able to document intermediate conditions such as must have existed if evolution has in fact occurred. We have. The question that was asked in the first place gets begged as well. Darwin suggested that the fossil record was far less complete than people thought. If so, then further research should lead to an increasing number of items lying close to A or B, and it has. Therefore the argument from lack of intermediates can be turned on its head, and made to show that evolution has in fact occurred, merely by adducing a few of them.
To refute the proposition that no intermediates occur, we need only show that one does occur: it is a formally valid test for universal negative proposition. (To refute "All men are immortal" it suffices to kill just one of them.) In the above example, B would suffice. But Denton accepts the creationists' version of logic, and insists that we find not just B, but A, and every other object in the universe analogous to it. In other words, he insists that we verify a universal affirmative. What this means is clear if we let the letters in our diagram stand for languages. Let B stand for Latin, C for French, D for Portuguese, E for Russian. In B, we do have a well documented common ancestor. But what about A? Unless I am mistaken, we have no documents of the common ancestor of the Slavic and Romance languages. And even if we did, the creationists would simply ask for the common ancestor of Nahuatl and Basque.
Such is the logic, if we may dignify fallacious reasoning with such an epithet, upon which "creation science" rests. That logic is inseparable from its content, for the movement has presented us with one long series of excuses for evading the canons of scientific evidence, in order to suppress truths that some people find objectionable. Insofar as special creation has been treated as a scientific hypothesis, it was decisively refuted in 1859. The only way to get around that fact is to repudiate not just some particular findings of science, but its very foundations in logic itself. But if logic -- and that means everything from higher mathematics to common sense -- has to be repudiated, then rational judgment of every kind loses its validity. That is precisely what the creationists want. If they can degrade your child's intellect enough, perhaps he will become one of them.
Denton's book may be read as an able piece of propaganda. As such it has many fine qualities. The rhetoric is by no means as bad as the logic. Except in a few places the author maintains a reasonable and earnest tone. The liberal use of end-notes suggests that a considerable amount of work has been done, and the reader unaware of what should have been cited but was not may have some difficulty distinguishing the reality of scholarship from mere appearances. The occasional use of creationist cliches tips off only the more perceptive reader to what motivates the author. The creationists need a book that is not overtly creationist at all, but purports to be motivated by purely scientific interests. So I do recommend the book, but only as an example of how reason is getting abused these days.
Denton's interpretation of percent divergence of protein sequences is wrong. He believes that it provides strong evidence against evolution, but it doesn't. He trys to show how different classes are isolated on a molecular level.
Denton looks at the % similarity between cytochrome c sequences of current organisms and claims that they all fall into "typological" groups, with nothing in between major groups. Thus, the various mammals all appear roughly equidistant from say, turtles, and all the reptiles all seem roughly equidistant from yeasts. Therefore he concludes that all organisms fall into their own distinct hierarchical categories with no obvious connection. His idea: Animals that look similar should require a similar genome.
Along the way he downplays the embarrassing fact that species of frogs, which can look pretty much alike, can display more sequence diversity than say whales and bats, who are morphologically quite distinct. This runs counter to his claim about morphological and sequence similarity.
Let's see more deeply with an example:
If Denton sees differences in cytochrome-c proteins between bacteria-shark and between bacteria-human is 85% then he falsely concludes that no evolution trees can be constructed. Denton claim that only following distinct hierarchical category can be made.
.........................................
. ........................ .
. ........ . ........ ........ . .
. . Bact . . .Shark . .Human . . .
. ........ . ........ ........ . .
. ........................ .
.........................................
(I'm not sure but I think Denton says "No trees can be seen..".)
BUT that is a very big mistake.
1) Computer scientists know that the picture above is really a tree! In Knuth,D.E.: Fundamental Algorithms, The Art of the Computer Programming, 2nd ed.,1981, p.307,309, picture 20 can be seen to be exactly same kind of picture as above. It is so called Venn's diagram, one of many ways to establish unambiguously a tree's structure !
O
. .
. O
. . .
Bact Shark Human
2) Differences or "distances" along tree are equal between Bact-Shark and Bact-Human. (Look: 5 dot's + 2 O's along tree in above picture.) So that's what is measured in protein level also. No contradiction with evolution tree ! In fact it proves evolution unlike Denton likes to show.
So what went wrong with Denton ? Denton's mistake is to imagine evolution to be in old aristotle-like style:
Bact
.
Shark
.
Human
(Or Bact -> Shark -> Human)
Denton also believes that nowadays bacteria is same stable archaea-bacteria as 3-4 billion years ago. And so on.
So Denton created aristotle-like building, painted slogan "Evolution" on it. Then he crushed it and now claims: "Evolution is crushed".
Well, after all the talk here, I finally went out and borrowed the thing to read. I'm about 1/3 through it and am going to quit. So far, it's a mishmash of evolutionary strawmen, out of context quotes, poor reasoning and worse analogies, and IMHO an example of intellectual dishonesty (possibly [likely?] unintentional) that it is not worth my time to finish it.
In the preface (third paragraph) we get "According to Darwin, all the design, order and complexity of life" [how's that for a judgment free description] "and the eerie purposefulness" [even worse] "of living systems were the result of a simple blind random process - natural selection." [It seems to me that we've sen this scarecrow before]. He repeats the 'blind random process=natural selection' several more times in the early chapters and then (p 85), after conceding that speciation and the process of natural selection are true, "Moreover, although there are some areas of disagreement among students of evolution as to the relative significance of natural selection as opposed to purely random processes such as genetic drift in the process of speciation, ...". So he knows that natural selection is not a purely random process yet he continuously equates it to such a process.
From chapter two, page 61:
"Darwin himself was often prone to self doubt over the sheer enormity of his own claims:".
Followed by the traditional creationist quote out of context concerning the eye including the traditional ellipsis.
He honestly describes the inherent difficulties in obtaining direct evidence (eye witness) for the largely historical parts of the theory of evolution, but then points to the dearth of such evidence as a telling blow against it.
He concedes microevolution (he's not stupid) but early in the book that appears to mean evolution within a species (as I understand it, the correct definition) but later, after he concedes speciation due to evolution, he equates it to evolution between "types". "Types" appears to be a non-religious code word for the biblical "kind". The definition boils down to 'we know what the bird kind^H^H^H^Htype is and we know what the cat type is and the boundaries are very definite. So I assert.'
Then there is the English sentence as an analogy for the (I guess) phenotype (but maybe genotype). Single letter changes while maintaining perfect spelling and grammar are allowed but any deviation from that is fatal. I suppose if misspellings, deletions, and inversions where meaning eb gleaned from context might be a reasonable analogy, but as stated, it is terrible. So too the 'watch with an extra gear' analogy. Sure the extra gear scews up a watch, but we know that gene duplication is common without being detrimental (in many cases it is a 'good thing')
I could go on, but it is a waste on top of the waste I've already invested.