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Which Part of Evolution Are We Talking About?

Post Author: Bill Pratt

I have followed the intelligent design (ID) movement for several years now and there is an error that I’ve seen opponents of ID make over and over.

The error is confusing the idea of common descent with the idea of random mutation and natural selection.

Common descent refers to the idea that all animal life is related, that if we trace back each living animal’s ancestry, we would find common ancestors.  If every animal could trace back its family history through ancestor.com, we would all find that we came from the same great, great, great (insert great thousands or millions of times) grandparents.  Some of us are closer relatives than others but we are all related if we go back far enough in history.  The idea of common descent can be supported by evidence from the fossil record and by comparing the DNA sequences of different kinds of animals.

The idea of random mutation and natural selection attempts to explain how animals have changed over time into all the diverse species we see today and in the fossil record.  Every time an animal reproduces, there is a chance for a genetic mutation occurring in the process.  If the mutation that the offspring inherits is helpful to its survival until it, too, can reproduce, well then the mutation is passed on to the next generation, and so on.

In this way, the genetic code is altered, and if enough of these mutations occur over time, you get a new species of animal.  The empirical evidence for this mechanism only demonstrates very small, and in many ways, trivial instances of change (e.g., finch beaks, peppered moths, antibiotic resistance, fruit fly mutations).  There is no empirical evidence of large scale evolution due to random mutation and natural selection (see Michael Behe’s The Edge of Evolution and my recent post on this topic).

Which idea does ID challenge?  Common descent or the mechanism of random mutation and natural selection?

ID theory almost exclusively addresses the mechanism of random mutation and natural selection, not common descent.  ID challenges the idea that complex, specified biological systems can develop through random mutation and natural selection.  Regardless of this fact, time and again, opponents of ID throw evidence of common descent at ID proponents, only revealing their ignorance of ID.  Just recently on this blog, as I was discussing the lack of empirical evidence for random mutation and natural selection, I was treated to commenters’ arguments again for common descent; the error seems pervasive.

It is time that we understand the difference between these two ideas.  I would love to hear good arguments against ID theory, but first ID opponents actually need to do some reading and try to understand what they are opposing.  Almost 9 times out 10, when I read opponents of ID, they badly  misunderstand the theory.  If anyone can point me to actual ID opponents who understand ID, I would much appreciate it.


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Comments

  • David

    Hi Bill:

    Christ is Risen!

    I would highly recommend that you listen to this lengthy, but very informative, 17 part lecture series on Darwin and Christianity:

    http://ancientfaith.com/podcasts/series/darwin_and_christianity

  • Andrew Ryan

    I don’t think ID actually qualifies as a theory, scientifically, so you can’t blame its opponents for any confusion.

  • Andrew Ryan

    “I would love to hear good arguments against ID theory”

    • Paul Draper wrote a well regarded critique of Michael Behe’s Darwin’s Black Box called “Irreducible Complexity and Darwinian Gradualism: A Reply to Michael J. Behe”.
    • See also Kenneth Miller in his book, Finding Darwin’s God.

    Did you follow the Kitzmiller v. Dover trial? I read Michael Chapman’s book on it, and it seemed to show the case for ID collapsing under MANY good arguments against it.

    Wiki: “Some of the most crucial exchanges in the trial occurred during Michael Behe’s cross-examination, where his testimony would prove devastating to the defence. Behe was forced to concede that “there are no peer reviewed articles by anyone advocating for intelligent design supported by pertinent experiments or calculations which provide detailed rigorous accounts of how intelligent design of any biological system occurred” and that his definition of ‘theory’ as applied to intelligent design was so loose that astrology would also qualify.

    “Earlier during his direct testimony, Behe had argued that a computer simulation of evolution he performed with Snoke shows that evolution is not likely to produce certain complex biochemical systems. Under cross examination however, Behe was forced to agree that “the number of prokaryotes in 1 ton of soil are 7 orders of magnitude higher than the population [it would take] to produce the disulfide bond” and that “it’s entirely possible that something that couldn’t be produced in the lab in two years… could be produced over three and half billlion years.”

  • http://sandwichesforsale.blogspot.com DagoodS

    a) What do you mean by “large scale evolution” in the sentence, “There is no empirical evidence of large scale evolution due to random mutation and natural selection…”

    b) What, explicitly, does the theory of evolution claim regarding empirical evidence and “large scale evolution”?

  • http://alabamatheist.blogspot.com/ Tim D.

    “Large scale” and “small scale” evolution are the exact same thing. There is no difference. One is just the accumulation of the other.

    Let me put it this way. The following scientific facts are pretty much undeniable by anyone with any degree of education in any biological field:

    -) DNA mutations happen when there is an error (usually very small) in the DNA replication process. Any DNA strand anywhere in the body is capable of mutating; so in principle, any DNA is capable of mutation — there are no “restrictions” on what kind of DNA mutation can occur. It is not true that, for example, only “small traits” can mutate, or that “body types cannot change through mutation.”

    -) It is true that large-scale mutations such as deformities are both (A) preposterously unlikely to happen in a single generation, and (B) are just as unlikely to be beneficial and thus be passed on to offspring, but it is not true that such mutations cannot happen. In principle, they very clearly and demonstrably can. Because “body type” mutations are the exact same thing as “beak size” or “skin color” mutations, at the basic biomolecular level — they are not “different types” of mutations, they are all mutations of DNA. Just that “large mutations” are made up of many, many small mutations. To argue anything other than this fact is to say that, although humans are made up of atoms, they do not have the properties of atoms. At the atomic level, they very well do have those properties, and the properties of atoms accumulate, overlap and interact in such a way as to give us the physical properties of our bodies.

    -) Random mutations happen all the time, more frequently than you might imagine. Most are benign, irrelevant or “transparent” (i.e. they affect sequences which don’t manifest as changes visible to the naked eye, and don’t noticeably alter any visible function of the body).

    -) If a trait which is beneficial to its organism manifests itself in this way, the organism is more likely to survive (and thus more likely to pass on the trait).

    -) If a trait which is harmful to its organism manifests itself in this way, the organism is more likely to be unsuccessful at surviving and reproducing.

    -) This effect can “overlap” or “stack” when individual mutations happen and are passed on, over successive generations — i.e. one parent mutates gene A and passes it to its offspring; the offspring, retaining gene A, experiences a mutation of gene C and now has both A and C mutated genes, which it passes to its offspring; the next generation (which now retains both A and C mutated genes) may experience another mutation. These changes accumulate gradually, often on a scale that is too small or transparent to be noticed. There is no mechanism which prevents this change from accumulating.

    The very fact that ID proponents even claim that “large and small mutations are different” betrays a staggering ignorance of what a mutation is. Mutations are mutations; large or small, immediate or accumulated, they are errors in DNA replication. They can literally cause any degree of change in the human body, and they happen in droves in every generation, just due to the sheer amount of DNA replicated during reproduction and development. It’s just that most of them are transparent, in that they don’t manifest in visible “traits.” We call these “recessive” genes. And when a recessive gene is mixed in with the right combination, it can manifest as a trait even if the parents did not exhibit that trait — diseases like Tay-sachs can manifest in this way.

    It is time that we understand the difference between these two ideas. I would love to hear good arguments against ID theory, but first ID opponents actually need to do some reading and try to understand what they are opposing. Almost 9 times out 10, when I read opponents of ID, they badly misunderstand the theory. If anyone can point me to actual ID opponents who understand ID, I would much appreciate it.

    There is no real difference between these two ideas. For one, common descent is only possible through genetic mutation and natural selection! By what other mechanism would you propose that animals can change in such a way as to be linked by common descent to other organisms?

    In this way, the genetic code is altered, and if enough of these mutations occur over time, you get a new species of animal. The empirical evidence for this mechanism only demonstrates very small, and in many ways, trivial instances of change (e.g., finch beaks, peppered moths, antibiotic resistance, fruit fly mutations). There is no empirical evidence of large scale evolution due to random mutation and natural selection (see Michael Behe’s The Edge of Evolution and my recent post on this topic).

    There is overwhelming evidence of large-scale evolution by random mutation and natural selection. You just need to look at the large scale of DNA evidence across many generations, through the lens of gradually-accumulated traits, instead of insisting on this line of reasoning where “there are no drastic mutations that take place over a few generations.” That is not what evolutionary biology claims. Large mutations do not usually happen at once; they usually accumulate gradually, through recessive or transparent mutations, and they accumulate until their combined interaction results in a visible trait. If this can happen on a small scale, then by definition it can happen on a large scale. There is no mechanism which exists to separate the two.

    So may I suggest, Mr. Pratt, that you are the one who needs to “do some research and find out what you are opposing?”

  • http://stranger-in-a-strange-world.myopenid.com/ Stranger

    sorry to say, but you seem to be missing some of the basic points of evolutionary theory: a) all change is the result of accumulated, gradual/incremental change. There is no grand divide between large scale and “minor” evolutionary change. b) The process of evolution is inherently *non-random* – selection works like a sorting algorithm. I don’t think you explicitly made the statement that selection was non-random, but the way this is framed sounds a bit misleading.

    Not that it matters, but so there’s no misinterpretation- I am a Christian (and a convert from atheism to boot).

  • Anonymous

    Hi Stranger,
    I get everything you said and have understood this for many years. With regard to (a), I agree except to say that there is one important reason that evolutionists themselves have differentiated between macro and micro evolution. We can directly observe micro evolution and we cannot directly observe macro evolution (where we see step-by-step one genus becoming a completely new genus).

    This kind of evolution just takes too long to be directly observed, so scientists must always infer it from fossils or DNA or some other indirect evidence.

    With regard to (b), evolutionary theory does say that genetic mutations are random, and that these mutations are what provide the material for the sorting algorithm of natural selection to work on. Without random mutation, natural selection would have nothing to select. So it is not true that evolution has no random component to it.

  • A “Berean” Christian

    The problem is that the “common descent” theory is that it is not provable. The DNA sequences could look alike because we descended from a single source or we simply look alike physically. I consider the other ID argument very strong. It reduces evolution to a faith-based mentality. I’ll stick with justifying my faith with the Gospel even so

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