Thursday, July 28, 2011

Models of Embryological Development

A post by 'Evolution News and Views' - a site discussing intelligent design and evolution - which deals with a classic 'proof' of evolution: embryogenesis. Good summary of the issues, discussion might be needed to flesh out the details if anyone is interested. It is part of a series, if you're interested in reading the whole lot.


I personally left this article with a bad taste in my mouth - despite agreeing completely with all the points they made - because of some slight arrogant undertones I thought I detected. Shouldn't complain though, I often feel the same after hearing/reading myself ;) Lord help us to present the truth in love and humility, boasting only in the cross of Christ and not our own 'rightness'!







Three Flawed Evolutionary Models of Embryological Development and One Correct One


Throughout this series on PZ Myers, evolution, and embryology, we have discussed four models of vertebrate embryo development. To help further simplify this debate, these four models are illustrated below and described. Please note that the first three models are flawed in varying degrees, and that some of the descriptions adapt language from the arguments of PZ Myers and various scientific papers.


Model 1 -- Haeckelian Recapitulation: Totally Flawed


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Discussion: According to this model of embryogenesis, evolution predicts that development will conserve the evolutionary history of an organism, which is replayed as an organism develops. As Haeckel's famous dictum said, ontogeny (development) recapitulates (replays) phylogeny (evolutionary history). This model is now essentially universally discarded by evolutionary biologists. Although Haeckelian recapitulation was abandoned long ago, many people have been taught it was true over the years. ID proponents recognize this fact, which is why we point out its falsity. However, we have a lot more to say than merely critiquing Model 1.

Unfortunately, PZ Myers typically misrepresents our arguments as if we're only and always attacking Model 1, when in fact we're usually attacking Models 2 and/or 3. Our main gripe with the usage of Haeckel's ideas in the modern era is not that they are used to bolster Model 1 (after all, Model 1 is rarely promoted these days), but rather that Haeckel's inaccurate drawings, which overstate the similarities between embryos, are still used to bolster Models 2 and/or 3. In any case, Model 1 is simply wrong because vertebrate embryos do not replay their supposed evolutionary history during development. The notion that 'ontogeny recapitulates phylogeny' is wrong.


Model 2 -- Funnel-Like Model: Highly Flawed


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(From Naoki Irie & Shigeru Kuratani, "Comparative transcriptome analysis reveals vertebrate phylotypic period during organogenesis," Nature Communications, Vol. 2:248 (2011).)


Discussion: According to this model, embryos start off developing similarly but become progressively different as time goes on. The evolutionary justification often given for this model is that precise developmental processes of the earliest stages of development are critical for later stages, and thus resistant to modification by mutation and selection. Evolution thus proceeds by modifying later stages of development since earlier stages which are more resistant to change. Under this model, evolution predicts that early development will be conserved (i.e. similar), and embryos will progressively diverge from one-another as development proceeds. This model is not supported by the data since early stages of vertebrate embryo development can vary widely.


Ideas inherent in this model are still found in many textbooks, which cite early similarities among vertebrate embryos as evidence of conserved stages of development which purportedly reflect their common ancestry. This model is inaccurate because early stages of development can vary greatly and show wide variation. PZ Myers also recognizes this fact. This means that he tacitly admits that a lot of textbooks are wrong.


Model 3 -- Hourglass Model: Flawed


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(From Michael K. Richardson et al., "There is no highly conserved embryonic stage in the vertebrates: implications for current theories of evolution and development," Anatomy and Embryology, Vol. 196:91-106 (1997).)


Discussion: Under this model, vertebrate embryos start off developing differently, but then converge at the phylotypic or pharyngular stage, showing substantial conserved similarities to one another that are said to provide evidence of common descent. According to this model, the specific morphology of the phylotype represents a literal foundation upon which the rest of development proceeds, and is resistant to evolutionary change, because there are too many later events that are dependent on it.


This is the model preferred by PZ Myers and many other leading evolutionary biologists, and it is also commonly promoted in textbooks. This model recognizes that early and late stages--and to a significant extent middle stages--of development can vary greatly and show wide variation. However, it claims that vertebrates go through a highly similar stage - the pharyngular, phylotypic, or tailbud stage - midway through development. This pharyngular stage is said to reflect important developmental patterns which have been resistant to evolutionary change ("conserved"), and thus the pharyngular stage is said to reflect their common evolutionary heritage.


But in the past 15 years or so, a number of leading evolutionary biologists have recognized that the phylotypic stage is simply "assumed to be particularly resistant to the action of natural selection" and "often discussed in terms that emphasise conserved features, and ignore variable features." When biologists carefully compare embryological data, they find that there is considerable variability at the purported phylotypic stage, leading increasing numbers of biologists to question whether this pharyngular stage exists. As a paper in Nature said last year: "both the model and the concept of the phylotypic period remain controversial subjects in the literature." PZ generally refuses to address this literature, but it nonetheless calls into question the very concept that defines this model and gives PZ's Pharyngula blog its name.


Model 4 -- Reality: Correct


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(From Jonathan Wells, Icons of Evolution (Regnery, 2000), Image Copyright Jody F. Sjogren 2000.)


Discussion This model simply lets the data speak for itself and does not try to force-fit some evolutionary interpretation to the data. This model acknowledges that there is wide variation in embryos at fertilization. Variation can and does occur between vertebrate embryos at every stage of development, and early and late stages -- and to a significant extent middle stages -- can and do vary greatly. Vertebrate embryos show some similarities -- but also many significant differences -- during the purported phylotypic stage. However, differences in body size, body plan, growth patterns, and growth timing show wide variation in morphology among vertebrate embryos which is difficult to reconcile with the idea of a phylogenetically-conserved stage. At best, there is a period of development where some general similarities emerge, but this looks very different than what is taught in most textbooks. These differences lead top embryologists to argue against the existence of a phylotypic stage in vertebrates. There is not a consistent pattern that is amenable to an easy evolutionary interpretation.


While there are some general hourglass-like patterns in vertebrate development, the pharyngular stage is called into question. Moreover, evolutionary biologists have struggled to explain how Darwinian processes could lead to hourglass-type patterns of development in the first place. As a 2011 paper in Nature Communications states:

One unanswered question in this field is how pharyngular stages became conserved. ... [H]ow did vertebrate embryos allow the early developmental stages to diverge while keeping the following stage essentially unchanged? For example, in spite of considerable phylogenetic divergence in the mechanisms of vertebrate germ layer formation and gastrulation among the four species we analysed, all these embryos pass through the conserved pharyngula stage.

(Naoki Irie & Shigeru Kuratani, "Comparative transcriptome analysis reveals vertebrate phylotypic period during organogenesis," Nature Communications, Vol. 2:248 (2011).)


As noted previously, from an evolutionary vantage, the evolution of vertebrate development almost appears goal-directed, where embryos if many taxa start off developing very differently but then converge on a somewhat similar stage midway. So how could Darwinian evolution preserve a midpoint of development as similar, when embryos start development so differently? The authors of this 2011 paper aren't sure, and their article grasps for an evolutionary explanation that almost hints at a goal-directed evolutionary process:

For example, in spite of considerable phylogenetic divergence in the mechanisms of vertebrate germ layer formation and gastrulation among the four species we analysed, all these embryos pass through the conserved pharyngula stage. How did vertebrates establish divergence of early embryogenesis while keeping pharyngular stages conserved? One reasonable deduction from this observation is that early vertebrate embryogenesis reduces the developmental fluctuations, which tend to occur around these stages, much like earthquake-resistant buildings that are built with the 'flexible structure'.

(Naoki Irie & Shigeru Kuratani, "Comparative transcriptome analysis reveals vertebrate phylotypic period during organogenesis," Nature Communications, Vol. 2:248 (2011).)


So early stages of development are "built" to divergently evolve in a way that reduces changes to later stages of development? And we find this same pattern of development repeated throughout many different species of vertebrates? This almost sounds like a goal-directed and non-Darwinian form of evolution, which is precisely why early differences between vertebrate embryos were not predicted or anticipated by many evolutionary biologists.


Again, the Reality Model simply lets the data speak for itself and doesn't try to force-fit some evolutionary pattern on to the data. While vertebrate embryos do show some similarities during the purported phylotypic stage, this model also reveals remarkable and significant differences at that supposed "stage." This model thus recognizes that there is wide variability and remarkable divergence at all stages of development.


Whether an evolutionary pattern can be fit to the actual data remains to be seen. But when PZ Myers is forced to say: "I wish I could get that one thought into these guys heads: evolutionary theory predicts differences as well as similarities," it seems clear that evolutionary biology is not predicting any model very well. If we just take the data at face value, the Reality Model is the most accurate model of vertebrate development.

24 comments:

  1. Hi guys! There's been a bit of discussion around this on Facebook. Thought I'd post the comments here on behalf of the participants (with their permission :) )

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  2. ‎PAUL SHOTBOLT -
    "Evolution News and Views" is a front organization for Discovery Institute schills. Author Casey Luskin fails to disclose his working relationship with Jonathan Wells, author of 'Icons of Evolution'. The criticism he is leveling at PZ Myers, lifted out of Well's book published in 2000, was explicitly refuted by PZ Myers in 2003, here: http://www.talkorigins.org​/faqs/wells/haeckel.html

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  3. ME -
    Thanks for that Paul,

    I bet you found these things on the web, right? Must be true then ;)

    Seriously though, both sites clearly advertise their connection - they are part of the same organization, essentially. And clearly Casey Luskin had a relationship with Jonathan Wells - I didn't think this needed disclosing…?

    Also, from what I could understand, the criticism is against a particular concept often used by the lay evolutionist (and certain variations of it by the academia too) as proof to their worldview. I's not agasint PZ Myers (although I don't doubt a lot of petty character assassination occurred from both sides).

    I am glad you supplied this link though, its an important part of the debate. Its the reason Luskin would been silly to just focus on one particular model - the one most people (including lay evolutionists and intelligent design proponents) seem to think is relevant. Instead he discussed how subsequent 'improved' models are wrong as well, including those concluded by the article you supplied.

    If you have anything to discuss regarding these other models, let us know! :)

    P.S. Do you mind if I copy and paste (or summarize in my own words, if you prefer) the comments you make into the comments at our blog? I think they are important for people to read. Let me know...

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  4. This comment has been removed by the author.

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  5. PAUL SHOTBOLT -
    I found them in two of Jonathan Wells' books that I read, not on the web. I recognized Luskin's name immediately, because I've been following this quack and his gaggle of co-workers for quite a few years now. You're welcome to copy and paste any of my responses onto your blog if you like. I happen to have read the book by Wells that Luskin loves so much, and I refer you to Well's own statements on page 98-99 in support of the general hourglass model, that Richardson rejects: NB: In the book it is actually *Wells* arguing for the hourglass model and complaining that it somehow refutes evolution. Luskin's citation of Wells criticising Myer's "preference for the hourglass model" is characteristically schizophrenic, and is just one more example of what happens when you actually look up the sources that these charlatans pay lip service to.

    Wells, Icons of Evolution, p98-99, in support of the hourglass model:

    "Surprisingly, after developing quite differently in their early stages, vertebrate embryos become somewhat similar midway through development. It is this midway point that Haeckel chose as the «first stage for his drawings. Although he greatly exaggerated the similarities at this stage, some similarities are there. Classical embryologists called this midpoint the tailbud stage.
    In 1976 William Ballard called it the pharyngula because of the paired ridges and pouches on either side of the pharynx. Klaus Sander proposed in 1983 to call it the «phylotypic stage, since it is here that the various classes first exhibit the characteristics common to all vertebrates.

    Some developmental biologists, however, point out that the midpoint at which vertebrate embryos are most similar is spread out over several stages. The phylotypic point is neither a point nor a stage, wrote Denis Duboule in 1994, but rather, a succession of stages. And according to Michael Richardson the phylotypic stage is a misleading concept that needs to be reassessed, because «in vertebrates, body plan characters develop over a long range of different stages, not just at one stage . Nevertheless, no one doubts that vertebrate embryos start out looking very different, converge in appearance midway through development (though not at the same time), then become increasingly more different as they continue toward adulthood. Duboule uses the metaphor of a developmental egg-timer to describe this pattern, while Rudolf Raff calls it the developmental hourglass. (Figure 5-4) Although von Baer's laws do not apply to embryonic stages before the middle of the developmental hourglass, they do appear to be roughly applicable to later stages. As Raff wrote in 1996: It should be noted that von Baer's laws provide an incomplete description of development.... In fact, he was dealing only with the later half of ontogeny."

    (in case it was unclear, Wells also never makes even a slightly compelling case for why the hourglass model -nor a more broadened hourglass model- would be somehow incompatible with Darwinian evolution. Read his book and see for yourself, if you feel like subjecting yourself to some remarkably dreadful scholarship...)

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  6. PAUL SHOTBOLT -
    I'd encourage everyone to read both viewpoints and decide for themselves, but unless you're ready to compare and contrast both -and double-check citations-then reading discovery institute propaganda is not a wise investment of time. The only reason I still do it is because the DI insists on waging their battles in public schools instead of conducting or publishing any actual academic research, and campaigns to replace your high school biology textbooks with their redefinition/inversion of science, (you can google the 'wedge document' for details).

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  7. ME -
    Hi Paul, thanks for permission to post comments. I think you raise an important points about scientific models that deserves a respone :) Personal emotions and biases are clearly important in what people see, perceive, and accept when they consider models - more than we like to admit. This goes for all people, not just evolutionists or Christians, and includes the most objective scientist. One can almost see it oozing out of your own comments too ;) Now emotional responses are good if they are appropriate and based upon truth, but easily prevent us from persuing knowledge if we allow them too much control over our perceptions, etc.

    My understanding is that Wells readily admits the realities a form of the 'hourglass' model (which he calls the reality model), which he believes supports intelligent design. He is trying to break through the extremes of 'idealization' that happen (i.e. the 'hourglass model' as it is typically understood by evolutionists) when people's emotional responses dominate and they try to make reality fit their own desires (i.e. an evolutionary worldview). Obviously if such things are happening it should be discouraged.

    I'm not saying Wells doesn't do the same thing. Rather we should careful to avoid falling into the same trap. Look at the article based on its own merits - most people DO misunderstand the realities of embryogenesis and how it fits into evolution/intelligent design paradigms. The hourglass model IS overly idealized most of the time. And it IS difficult (but not impossible) to provide an evolutionary explanation.

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  8. PAUL SHOTBOLT -
    "And it IS difficult (but not impossible) to provide an evolutionary explanation." It sure is, because Wells and Luskin can't even seem to keep track of whether "the hourglass model is appropriate and can't be explained by those meany evolutionists' or 'the hourglass model is what the evolutionists like PZ Myers support but it doesn't fit reality.' The truth of the matter is, they just don't care. They don't care because they are not arguing in good faith. They are not interested in reading articles honestly or charitably because they are not interested in the possibility that they could be wrong, and so they are not interested in identifying and eliminating their biases- something which you -thankfully- still seem to care about.

    But they don't care about that, which is is why you find yourself reading articles about evolutionary biology by Luskin who is a Lawyer with a degree in Earth Sciences. SC Meyers is an Earth Scientist. Johnson -who started ID- is a Lawyer. Jonathan Wells began his (relevant!) biology degree with the express purpose of attacking evolution under dictate of Sun Myung Moon (ie that was a conclusion he decided before even educating himself about the facts). Behe (the only other DI schill with an actual relevant qualification) accepts common descent, whereas Wells doesn't, which you might think would be incredibly alarming for the Discovery Institute if it was honestly concerned about forming a cohesive alternative theory rather than spouting propaganda and FUD.

    All of these hacks are employed by the same institution to create incestuous articles that prop each other up like a house of cards, and Joshua if you are remotely interested in honest debate you will read each of these idiots, and what they cite, identify enough instances of wilful misquotation and dishonesty to realise they are not at all interested in dialogue, and you will reject them as I did when I was still a Creationist. For a good while afterwards I counted myself as a Creationist who sadly realised he had no author of integrity and respect still championing my cause. Because it is not about the conclusions we reach, but whether we approach competing hypotheses with honesty and integrity and the humility to try and understand where we might be mistaken. You won't find a single DI fellow with these qualities, and their dishonest actions are an embarrassment to honest Christians everywhere. Maybe Hugh Ross at R2B might be, but there isn’t an honest man to be found among the DI, and I feel entitled to make such a claim only after reading their books (not before).

    Lastly, Luskin’s clear intent with his article (regardless of his self-contradictory content) is to make it look like there is sufficient disparity between biologists ideas of embryological development versus the actual data (photographs etc) to throw evolutionary theorists into some sort of crisis. Richardson, the author published the 1997 paper arguing that the pharyngula stage is an oversimplification -the paper central to Luskin’s plea- finds that claim quite laughable:

    http://www.talkorigins.org​/faqs/wells/iconob.html#ha​eckel-embryo

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  9. ME -
    I'm not nearly as interested in the personal character of the authors (or the evolutionists they are attacking, or yourself), as I am in the words on the page I posted. I can see flaws in everyone's character if I wanted to (including myself), and it especially saddens me if I see those who take the name of Christ, not maintain control over their own emotions to be more Christlike. But my responsibility is toward my own character - I do not want to make these mistakes. I want to seek truth and have appropriate responses to that truth (sometimes, the appropriate response IS strong emotion). But your comments have been quite distracting from this aim, so far (for me, anyway)…

    The words on the page I posted are interesting and thought provoking and mostly true (I think - when taken at face value). And realize too that these people change terms all the time like poorly trained debaters, while their actual points may not change - I think Wells and Luskin have consistently argued that a less-simplified hourglass model (the reality model) is appropriate and supports ID better than evolution. The motivations, foundation, and implications that the AUTHORS may have for this might be completely wrong. But am completely able to accept and reject the motivations, implications, foundations, and the idea itself - all independently.

    I'm interested that you agreed that it is difficult to provide an evolutionary explanation for a 'non-idealized' (i.e. realistic) hourglass model. I agree ;) but I'm not sure if I understood you correctly - what exactly do you mean?

    I'm also interested to hear you talk more favorably about RTB and Hugh Ross - can you describe what it is about them that makes your feel differently?

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  10. PAUL SHOTBOLT -
    As far as I'm concerned the difference between Hugh Ross and these guys is that I have read a great deal of the DI's work over the last 6 years, and I haven't read nearly as much of Dr. Ross's. I'm not going to attack Dr. Ross's honesty just because I don't agree with his conclusions; I am attacking the credibility of the DI fellows because I've read enough of their work to have a meaningful sense of whether their scholarship is honest or dishonest.

    What you have just told me by dismissing this is that you're not interested in the credibility of your expert testimony- this is an utter abdication of responsibility. A first year paper in critical thinking would teach you that expert testimony is considered credible if there is: the expert is giving their honest opinion (demonstrably false), and expert is speaking on a subject they are trained in (false in Luskin's case), and sufficient consensus among experts (in this case, the consensus among developmental biologists / embryologists appears to be united in support of ToE with… one dissenter named Jonathan Wells)

    "I'm interested that you agreed that it is difficult to provide an evolutionary explanation for a 'non-idealized' (i.e. realistic) hourglass model. " I didn't agree with that proposition at all. Neither does Richardson -whose expert opinion I linked to and who conducted the research in question- he doesn't think an hourglass nor a widened hourglass presents any difficulties for ToE either. Luskin has no relevant training nor has he conducted research in this field, and wouldn't know one way or the other. Wells -the only ID proponent cited who actually has relevant training can't even (I encourage you to read his chapter on this if you disagree- the 'Model 4: Reality' diagram Luskin uses is actually lifted from page 95 of Wells' book icons of evolution, in the section where Wells uses the diagram to explicitly argue that "The earliest stages in vertebrate embryos are not the most similar". Wells then goes on to arrive at: you guessed it, "Model 3: The hourglass", using this diagram ( http://imgur.com/a471H ) on page 100 (which even uses the same individual compnents as the earlier diagram!) arguing that the *hourglass* is the appropriate model. He then spends the next couple of pages trying to make it sound as though darwinian evolution would necessitate or at least heavily imply that the most similar stage of embryological development must be the earliest, that the hourglass model refutes that and that therefore A Magic Man Did It. You will note that neither Luskin nor Wells cites any contemporary sources that support this idea that the ToE would be in conflict with the hourglass model, broadened or otherwise. This is because they don't have any such sources.

    As I have said earlier, please read the source material they cite (Wells, Richardson, and PZ Myers) and decide for yourself. Have you actually read Wells' book?

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  11. PAUL SHOTBOLT -
    To clarify my earlier comment, where I said ""And it IS difficult (but not impossible) to provide an evolutionary explanation." I was referring to the fact that it's pretty difficult to provide an explanation to satisfy someone who keeps 'changing the goalposts' (which I then explained how Wells and Luskin are doing exactly that). If you are not already familiar with this term and its rampant use in denialism movements (including antivax movements and climate science denialists) I would encourage you to read further on the topic: It is a cynical marketing strategy that takes the 'good faith' completely out of the debate; it is the opposite of what scientific thought really is, which -under Popper's and Feynman's views- is explicitly and overwhelmingly concerned with rigorous attention to bias. Feynman describes it as (paraphrasing) 'bending over backwards to see how I could be wrong'. If I ever encounter a professional Creationist / IDprop who fits that bill, I'll eat my hat. It would be nice if Hugh Ross turns out to be the first.

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  12. ME -
    Paul, you know me better than all that!

    The idea of 'expert testimony' applies to a source of justification for beliefs. I am not using their 'expert testimony' in any way to justify my beliefs - its just an interesting article which I think (taken at face value) describes some aspects of my belief system quite well. But my belief system is already justified elsewhere. So I am quite happy to disregard your perception of their character - to better help everyone think clearly about the points raised.

    The problems you seem to have identified with ID proponents are actually universal. Most people (from all camps, including ToE) will use 'expert testimony' very poorly, and regularly 'change the goalposts' (my personal experience is that anti-theists do this most frequently). And there are very VERY few scientists who actually adhere to the ideals of naive falsificationism (which is why sophisticated falsificationism is required).

    When I have time I want to write a series of posts on the philosophy of science. But at this rate (with study and all), that might be next year sometime ;)

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  13. PAUL SHOTBOLT -
    You are implicitly relying on expert testimony that the hourglass model - or broadened one- or ' reality' (whichever) is somehow incompatible or at least problematic for ToE, that and (it is implied) would better be explained by some murky, unspecified alternative to common descent. There implication is central to both Wells and Luskin, but there is nothing in your linked article or in the original source in Wells' book that backs up such a claim. You have contended that ToE has difficulty here yourself in your comments, and I'm sure that you are honest enough to admit the implication that evolutionary theory is somehow insufficient/inadequate/mi​sguided here is a reason you found the article attractive enough to link to in the first place. It is only the opinions of those two 'experts' that the described process is problematic for ToE. You are therefore relying on expert testimony. Therefore the credibility of these 'experts' and their past history of dishonesty, personally and among their organization is admissible when disputing that point.

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  14. ME -
    Don't jump to conclusions:

    - I linked to this article because it succinctly described some aspects of my existing knowledge-belief paradigm. I wanted people to think about these issues.
    - I'm not relying on these authors' expert testimony to justify all that, in any way.
    - I personally think that there are better explanations for this phenomenon than evolution. This does not necessarily mean evolution is unable to provide an explanation.
    - You assume that 'common descent' is not 'murky', while all alternatives are - I think this is misguided.

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  16. PAUL SHOTBOLT -
    Take some responsibility. First you feel the the article is notable enough to quote the entirety of, verbatim, without commentary (blogspam much?). You clearly didn't feel that it was out of line enough to critique yourself. After the authors' credibility and credentials are shredded you then decide expertise isn't really relevant to trivial fields like embryology. Then you decide to whitewash your later personal comments that ToE has difficulty explaining the model, when neither you nor Wells nor Luskin has at any point backed up such a claim, whereas I have provided expert testimony to the contrary from Richardson himself. What you're doing isn't outright lying, but it is a dishonest form of reasoning where you put forward your arguments and then later minimise them saying they're not the *real* reason you hold to your conclusions anyway. Maybe they weren't how you got to your position, but the rank dishonesty evident in the most prominent leaders of the ID platform should give you more than enough cause to check their sources, and cause you to search for more honest champions for your cause.

    "I personally think that there are better explanations for this phenomenon than evolution. "

    I personally think you should read the author's book and see how dishonest he is. I personally think you bear that responsibility if you're going to propagate their views, especially if you hope to use your profession and training to lend support to disguised religious arguments involving tangental fields like embryology. I personally feel that you have a responsibility to identify, reject and denounce dishonest authors whether they happen to agree with your precious conclusions or not. You can dispute that if you wish.

    "You assume that 'common descent' is not 'murky', while all alternatives are - I think this is misguided."

    I'm not assuming any such thing- I'm talking about Wells' books, and *his alternative* (which is the one I was referring to at the time) is murky to the point where he can't seem to come out and say whether common descent is part of his theistic evolutionary alternative or not. You cannot meaningfully dispute this unless you're prepared to read his book. This is the standard approach of DI schills everywhere, which is to not have any meaningful alternative model in mind, never take a firm stance on any particular issue (even one as central as common descent) and instead try to spread FUD regarding actual research (which is never conducted by the DI itself or they might have to defend it), in order to facilitate their sickeningly political -as opposed to scientific- goals.

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  17. ME -
    We all know how you feel about DI by now Paul. You have entirely missed the purpose of my post and the blog, which I think is why you get frustrated by my responses. I don't necessarily 'propagate the views' of the articles I post (at least, not all the views all of the time), and our purpose is not to 'denouce dishonest authors'. Its to inspire improving knowledge-belief paradigms and appropriate responses to these (and I believe this process ultimately leads to faith in Christ). Even evil can inspire an improved paradigm. If you're going to comment, discuss the paradigms that do, should, or might exist around acceptance / rejection of each of the ideas presented in the article. I'm glad you brought up the problems with the author's particular paradigms - great. We've flogged that horse. Let's move on... comment in the spirit of inspiration, not distraction, and not destruction of good thinking just because it springs from something you don't like.

    Posting the article verbatim does not mean I think it is 'notable' in the sense that it should be respected as 'expert opinion', rather that it is notable in its ability to describe paradigms and inspire thought and improvement of existing paradigms. I wanted people to discuss the scientific issues, something your repetitive focus on character assassination has somewhat obscured. I assumed you had finally made a point about the general scientific issues, with your comment about 'murkiness' - but apparently I was wrong, you were still focussing on the authors of this particular paper. Your favored 'experts' deal nicely with their understanding of the author's paradigms. Great. Lets expand our focus to discuss other idea/paradigms. I do believe that expert opinion is completely relevant - just not necessarily THESE author's opinions (they aren't in my case). Its just a thought-provoking article that points to bigger issues beyond itself. Speaking of which...

    I understand your desire to have me completely explore the scientific issues in writing and explain the justification for my belief system. However I'm afraid its unrealistic. Science and knowledge do not exist in isolated sets of beliefs - but as whole paradigms. And describing and justifying an entire paradigm will take a very long time. And I'm very very busy studying. So we'll all have to put up with each giving little snapshots at a time, and using these to our best advantage to inspire constructive thought. I will keep posting thought-provoking articles with very brief comments, expecting others to discuss appropriately, and being picky in which comments I reply to (this stream hasn't been too difficult, especially since there's a lot of repetition).

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  18. PAUL SHOTBOLT -
    I apologize that my reading of your linked article and previous in-depth reading of the original book which inspired that said article unearthed some glaring internal contradictions that you find inconvenient. To avoid this unpleasant situation in future, either I could offer to not comment on your linked articles, or you can link to honest sources. I would think the later choice is preferable, but I would not presume to make the choice for you.

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  19. ME -
    Paul you're still missing the point! Don't get offended - glaring internal contradictions need pointing out, they're not inconvenient. But they've been pointed out. I just want to move on to more constructive discussion - without assuming the article will never lead to any good, and without assuming that those who read it / find it interesting / thought provoking are as evil as you perceive the authors to be.

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  20. PAUL SHOTBOLT -
    "without assuming that those who find it thought provoking are as evil as you perceive the authors to be". I find basically all laymen who read and discuss DI articles to be acting in good faith. My displeasure toward the DI authors is only enhanced by this, because Christians are in general rather nice, earnest and sincere, and I feel they deserve better champions for their viewpoint (I feel quite similarly about the catholic hierarchy vs individual Catholics). I hope my (informed) vehemence against both institutions is distinguishable from vehemence against the generally honest and sincere individuals who are-variously- consumers or congregants.

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  21. ME -
    Well, it wasn't actually that easy to distinguish, so thanks for clearing that up. I feel much better being a 'layman/consumer/congregant who is acting in good faith, and is in general rather nice, earnest, and sincere, and who deserves a better champion for my viewpoint'. (Though there's an obvious patronizing attitude there).

    Sure, there are heaps of people in all camps that don't recognize the evils of the world we live in. But I am one of the worst cynics out there, man - generally I'm the one pointing these things out to others ;) Very few people are worthy of the title 'champion of the faith' - whether that faith is theistic or anti-theistic.

    But any old article can be interesting. I'm sorry my (informed) interest and non-vehemence wasn't obviously distinguishable, from full approval of the paradigms that do/may exist in the minds of the authors behind the article. I tried to include a mild disclaimer in my brief commentary - next time I'll make it more explicit!

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  22. Paul, I am sure that Josh and I would be quite happy to share something good that someone like Dawkins might author, but it doesn't necessarily mean that we think highly of his authorship in general.

    Content wise, an interesting article Josh, thankyou.

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  23. Thanks DP, I apprciate it! :)

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  24. And you're right DP about my attitude toward Dawkins. Its unfortunate that this stream of comments arose before I could write a proper post about the philosophy of science - a lot of what was said here, I had hoped to deal with in those posts! This should serve to refine the focus for any such posts, though, so its good in a sense... one day when I have time... :)

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