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Denton, Still a Theory in Crisis, Part 3

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This is the third of a series of posts reviewing Michael Denton’s new book Evolution: Still a Theory in Crisis.

This is a good time in our discussion to note that the title of Denton’s book has resulted in considerable unnecessary confusion, because far from believing that “evolution” as such is a theory in crisis, as we have seen, Denton is a firm believer in evolution defined as descent with modification.  Denton believes that the specific evolutionary theory of Neo-Darwinism is in crisis, and he wanted to title his book “Neo-Darwinism: A Theory in Crisis,” but his publisher prevailed upon him to use the more widely used, but far less accurate, term.

In Chapter 3 Denton notes that everyone agrees that all living things (whether currently existing or extinct) can be grouped within taxa that form nested hierarchies.  Prior to Darwin most biologists believed that these taxa were immutable natural “types.”  These pre-Darwinian typologists have been roundly criticized for allowing their metaphysics to color their views.  After Darwin everyone knows organisms are infinitely mutable, and only a credulous rube held in thrall to superstition would believe otherwise.  Denton begs to differ.  The existence of fixed types is not a metaphysical position; it is an empirical position based on taking the data at face value:

Today, 150 years after Darwin, [Richard] Owen’s “biological atoms” are still as distinct as ever.  The vast majority of all organisms can be assigned to distinct and unique classes based on their possession of particular defining homologs or novelties which are not led up to via Darwin’s “innumerable transitional forms.”

Homology is the relationship between biological structures or sequences that are derived from an assumed common ancestor.  A homologous trait is often called a homolog.  Taxa are defined by “suites of homologs.”  For example, the human body exhibits homologs that group it in (in descending taxonomic order): tetrapod (all terrestrial vertebrates); amniotic membrane (all higher vertebrates); diaphragm (all mammals), etc.

Denton discusses several taxa-defining homologs, including the pentadactyl limb that is shared by all extant terrestrial vertebrates; the feather shared by all modern birds; the insect body plan shared by all insects; and the flower, which is shared by all higher angiosperms (eudicots).  Denton notes that these “types,” if you will, exist and there is simply no long series of adaptive transitional forms between them and their taxonomic neighbors.

Instead, the record is largely one of DISCONTINUITY between the taxonomic types, and that record is exactly the opposite of what Darwinism predicts.

Denton comes back to this theme again and again.  If Darwinism were the whole story, suites of taxa-defining homologs not led up to by a long series of transitional forms should not exist.  Yet this is seen over and over.  Denton emphasizes that this is not a “creationist” view.  He quotes Rupert Riedl, a convinced evolutionist, a world authority on marine invertebrates, and one of the foremost biological theorists in the last quarter of the twentieth century:

Although such fixation [the invariance of the taxa-defining traits] may not be self-evident to some of my colleagues, I must emphasize that in accepting the evolutionary history of taxonomic groups the fixation of homologues is a logical necessity.  Thus for example, the chorda remains a chorda in all chordates from ascidians to man; the backbone remains a backbone in all vertebrates, from frog to python; and a particular digit remains the same digit in all tetrapods from horses to bats.

Denton then gets to the point of all of this:

 

Ironically, as Riedl argues, it is only because organisms can be classified into distinct groups on the basis of their possession of invariant unique homologs that descent with modification can be inferred in the first place. If it was not for the invariance of the homologs and the Types they define, the very notion of the common descent of all the members of a particular clade from a common ancestor would be in serious doubt. The living realm would conform to a chaotic network rather than an orderly branching tree.

Denton notes that again, his view that taxa-defining homologs define real “types” is well within the mainstream of evolutionary biology.  He quotes Gareth Nelson and Norman Platnick:

Since the advent of the so-called new Systematics, it has become popular to deprecate as “essentialistic” or “typological” the notions that species (and hence groups of them) have defining characters, and that it is the business of systematics to find them… The rationale for this deprecation seems to be that if evolution occurs, the characters of species (and hence groups) may change in the future; therefore, species and groups of species cannot be permanently characterized by means of a single character or set of characters such that the character or set is necessary and sufficient for membership in the species or group. The argument seems to rest on the misleading use of character states: it assumes that when a species is modified, and acquires a new apomorphic character (state), it is no longer recognizable as having, the original plesiomorphic character (state). In other words, according to this argument, we cannot use characters (such as fins) to define groups (such as Vertebrata), because some members of those groups (such as tetrapods) may acquire apomorphies (such as limbs). If one accepts the validity of ontogeny or outgroup comparison (i.e., Parsimony) or any other possible test of hypotheses about character transformation, the argument is obviated. In this sense, systematists always have been, are, will be, and should be typologists.

 

Gareth Nelson and Norman Platnick, Systematics and Biogeography (New York: Columbia University Press, 1981), 328, emphasis added.

More irony.  Foaming at the mouth Darwinian cladists like Nick Matzke unwittingly support the structuralist paradigm over the Darwinian functionalist paradigm by the very nature of what they do.  Denton writes:

The cladistics enterprise would be impossible if different groups were not unambiguously defined by synapomorphies (homologs unique to those particular groups). Indeed, current evolutionary literature is replete with thousands of cladograms to illustrate the phylogeny of various groups of organisms and the sequence in which the various defining traits of the subgroups were acquired.

Which brings us back to where we began.  Denton is not a creationist.  He is not even an ID proponent, if ID is defined in a narrowly interventionist way.  He firmly believes in the tree of life and common descent.  If Denton does not believe the “types” arose though Darwinian processes and he does not believe they arose through interventionist acts of a designer, what does he believe?  He believes the types were “prefigured into the order of things from the beginning.”  From this I surmise he is a front-loading ID proponent.  He summarizes his position as follows:

Although I think the evidence is consistent with most of the novelties being achieved in a relatively saltational manner typology does not demand absolute saltation, just that the Types (or more properly the homologs which define them) are a special set of robust natural forms or stable material systems, part of nature’s order from the moment of creation, to which the paths of evolution were inevitably drawn.

 

Comments
CancelStephenB
February 22, 2016
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I find the discussions about Naturalistic views and assumptions kind of interesting insofar as they bring their baggage to the table. You know what they are going to say most of the time before they say it. I actually changed my mind about interpreting the fossil record as time went by as I became more acquainted with the facts. I just wanted to know what was true and how it fit together. Darwinism was in crisis from the publishing of Origins and it was mostly scientists who said it was nonsense. They knew the fossil record didn't show what Darwin's hypothesis said what "it would eventually as the record is poor and incomplete". It still pretty much that way. Yet some Christians believe in evolution. The person, B.B. Warfield, the Lion of Princeton was the one who wrote the essay on the inerrancy of the Bible and most Evangelicals use his argument still. Most do not know that it came from Benjamin Breckenridge Warfield. Funny thing about him was he leaned towards evolution, but some argue that he didn't, but he did. Note I didn't say he embraced it, but he didn't think it was that important. His successor John Gresham Machen thought Warfield was one of the greatest Christian minds, but he had to struggle with the church after Warfield died as he wrote his most well known work Christianity and Liberalism. He would start the Presbyterian Orthodox Church (now Presbyterian Church of America, PCA) and open Westminster Seminary. They were theologians and in Machen's case something of a societal reformer as he thought the church should be the conscience of society. They just didn't think much about evolution and in Machen's case it wasn't in much esteem in his short life. He died at 54 fighting the influence of the liberal church and it's low view of Scripture and the Confessions. I have met many Christians who claim to have a high view of the Bible and they do not know many major doctrines. I met a young lady who grew up in the church and she didn't know that Jesus was God incarnate. The ignorance of so many I have met in the Church shows a lack of teaching and a lot of majoring in minors and minoring in majors. Scientists nowadays are trying to be philosophers and it is obvious they haven't taken Philosophy 101, the art of critical thinking. They really should. When Philip Johnson, a lawyer writes a book that I still reference, Darwin On Trial and it is still causing ripples in the biological sciences. What Science is will depend on the philosophical assumptions of the person you ask. Sometimes you get a fairly accurate answer, but the rush to get rid of the falsification requirement will spell the end of any respect that Science still retains. Depending upon the subject I'm reading about I have to read carefully as the presuppositions of the writer will too often influence the facts he presents and the data he ignores. A book could be written about most Science along the lines of liberal and true science. Look at the politicization of Climate Change. The solutions they are putting forth are a guarantee that they won't be believed. That is a lot of Science nowadays.jimmontg
February 20, 2016
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Barry says:
He believes the types were “prefigured into the order of things from the beginning.” From this I surmise he is a front-loading ID proponent.
Being prefigured into the order of things is the core tenet of Theistic Evolution, Evolutionary Creationism: https://en.wikipedia.org/wiki/Theistic_evolution http://biologos.org/common-questions/christianity-and-science/biologos-id-creationism/ Michael Denton:
Although I think the evidence is consistent with most of the novelties being achieved in a relatively saltational manner typology does not demand absolute saltation, just that the Types (or more properly the homologs which define them) are a special set of robust natural forms or stable material systems, part of nature’s order from the moment of creation, to which the paths of evolution were inevitably drawn.
Charles Darwin:
There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone circling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.
GaryGaulin
February 18, 2016
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Denton comes back to this theme again and again.
So far Denton has only one thing to say. He is a one note Samba. It is
It could not have happened by Neo Darwinian means.
But Darwin's ideas updated with genetics and genomes are not that sacred. What is sacred is a naturalistic process that led to all the taxa/species/novelites. If one could be found that did not involve Darwin's ideas, Darwin would be abandoned in a second, no a nano second. He would be a Kuhnian example of how theories change with new information. Darwin would still be revered as is Newton who as revered as he was, was replaced by Einstein. But no one has a credible theory that explains anything, so Darwin is still the darling of the faithful. Along comes Denton who is ostensibly no different from the many others opposing Darwinian gradualism but has nothing else to offer than stating the obvious. What are we to make of him. Will the later chapters provide anything. I haven't read them yet, but based on the lack of noise, I expect the Samba to continue playing till the end and we are back where we were before but with more ammunition that Darwin is toast and there is no other theory. Maybe this is Denton's way of pointing to a designer as the obvious explanation.jerry
February 18, 2016
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Taking homology seriously inevitably leads one to a mode of thinking that was out of favor during most of the twentieth century ... typology naturally emerged from the facts of evolutionary developmental biology and it would be seriously problematic to try to avoid it. – Gunter P. Wagner
Mung
February 18, 2016
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Have you noticed the word "creation" in the last sentence of the quote?? Uuuhhmmmmm ... What could that mean?Anaxagoras
February 18, 2016
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This is a good time in our discussion to note that the title of Denton’s book has resulted in considerable unnecessary confusion, because far from believing that “evolution” as such is a theory in crisis, as we have seen, Denton is a firm believer in evolution defined as descent with modification.
I was anxiously awaiting your discovery of this minor detail.GaryGaulin
February 18, 2016
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Don't give credence to the anti-ID crackpots who will say anything and everything about what Denton writes or believes without having read his book. And Denton is not alone. http://onlinelibrary.wiley.com/doi/10.1111/bij.12458/pdf https://sysbio.oxfordjournals.org/content/64/2/365.extractMung
February 18, 2016
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Dentons book is good for its well made attacks on big ideas in modern evolution. YEC does not see the nests or need to. A common design explains better all. Again also there should not in biological discussions be any talk of fossils. The fossils say nothing about biology except presumptions of desposition. Without the geology concepts there is no biology to be gleaned from fossils. sO this means there is no biology in the fossils. No biology process are shown by fossils!! Evolutionists got away with this for centuries and ID/YEC must not do it too. Its not scientific. biology hypothesis and knocking same out must be on biology. You can't ket this go even with the good guys. Lets be scientific and only stick to biology evidences for processes and results. No rocks with pictures of static movements.Robert Byers
February 17, 2016
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