Sunday, October 09, 2005

Dawkins on the bacterial flagellum's "tiny molecular motor" #1

In his "The Ancestor's Tale" (2004), leading atheist and Darwinist, Oxford University's Richard Dawkins, discusses the bacterial flagellar rotary motor and dismisses, with fallacious arguments, biochemistry professor Michael Behe's `irreducible complexity' argument for intelligent design (ID). Significantly, Dawkins offers no Darwinian, natural selection of random micromutations, explanation of how a `blind watchmaker' put together this "engine and drive mechanism ... composed of 40 parts, including a rotor, stator, driveshaft, bushings, universal joint, and flexible propeller ... powered by a flow of ions ... at up to 100,000 rpm ... and can reverse direction in a quarter of a rotation. ... with an automatic feedback control mechanism:

"IMAGINE A NANOTECHNOLOGY MACHINE far beyond the state of the art: a microminiaturized rotary motor and propeller system that drives a tiny vessel through liquid. The engine and drive mechanism are composed of 40 parts, including a rotor, stator, driveshaft, bushings, universal joint, and flexible propeller. The engine is powered by a flow of ions, can rotate at up to 100,000 rpm ... and can reverse direction in a quarter of a rotation. The system comes with an automatic feedback control mechanism. The engine itself is about 1/100,000th of an inch wide -- far smaller than can be seen by the human eye. Most of us would be pleasantly surprised to learn that some genius had designed such an engineering triumph. What might come as a greater surprise is that there is a dominant faction in the scientific community that is prepared to defend, at all costs, the assertion that this marvelous device could not possibly have been designed, must have been produced blindly by unintelligent material forces, and only gives the appearance -- we said appearance! -- of being designed. As you may have guessed, these astonishingly complex, tiny, and efficient engines exist. Millions of them exist inside you, in fact. They are true rotary motors that drive the "bacterial flagellum," a whip-like propulsion device for certain bacteria, including the famous E. coli that lives in your digestive system." (Peterson D., "The Little Engine That Could...Undo Darwinism," The American Spectator," 8 May 2005).

[Above: The bacterial flagellum: "Organelles Or Parts of a Eukaryotic Cell A Study Guide For Mr. Lowell’s Science Class," Maine School Administrative District #42: "A true axle, a freely rotating hub ... driven by a tiny molecular motor"]

My comments are in square brackets.

"Bacteria ... are supremely versatile chemists. They are also the only non-human creatures known to me who have developed that icon of human civilisation, the wheel. ... THE WHEEL is the proverbial human invention. Take apart any machine of more than rudimentary complexity and you'll find wheels. ... Whenever humans have a good idea, zoologists have grown accustomed to finding it anticipated in the animal kingdom. ... Why not the wheel? ... There is one revealing exception to my premise. Some very small creatures have evolved the wheel in the fullest sense of the word. The wheel may even have been the first locomotor device ever evolved, given that for most of its first 2 billion years, life consisted of nothing but bacteria. Many bacteria, of which Rhizobium is typical, swim using thread-like spiral propellors, each driven by its own continuously rotating propellor shaft. It used to be thought that these `flagella' were wagged like tails, the appearance of spiral rotation resulting from a wave of motion passing along the length of the flagellum, as in a wriggling snake. The truth is much more remarkable. The bacterial flagellum is attached to a shaft that rotates freely and indefinitely in a hole that runs through the cell wall. This is a true axle, a freely rotating hub. It is driven by a tiny molecular motor which uses the same biophysical principles as a muscle. But a muscle is a reciprocating engine, which, after contracting, has to lengthen again to prepare for a new power stroke. The bacterial motor just keeps on going in the same direction: a molecular turbine." (Dawkins R., "The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution," Houghton Mifflin Co: Boston MA, 2004, pp.543,547)

[In fact the late leading Darwinist mathematician-geneticist, J.B.S. Haldane, in the 1940s explained the reason that "one finds no example of ... the wheel" in nature (so he thought) is that it "would be useless till fairly perfect" and therefore its existence would "make [it] necessary to postulate a leap which would imply prevision by a designer"!:

"There are, of course, difficulties in the theory of evolution. ... I agree with you that some processes, such as the evolution of the mammalian ear bones, probably occurred by sudden leaps. ... It is never, however, necessary to postulate a leap which would imply prevision by a designer. That is why one finds no example of various mechanisms, such as the wheel and magnet, which would be useless till fairly perfect." (Haldane J.B.S., "Haldane to Dewar," in "Is Evolution A Myth?," C.A. Watts & Co. Ltd/The Paternoster Press: London, 1949, p.90).
The graphic above of this "molecular turbine" is the original from Voet & Voet, Biochemistry (1994, Wiley, p.1529), which Dawkins has a simplified drawing of at the top of p.548.]

"The fact that only very small creatures have evolved the wheel suggests what may be the most plausible reason why larger creatures have not. ... A large creature would need big wheels which, unlike man-made ones, would have to grow in situ rather than being separately fashioned out of dead materials and then mounted. For a large, living organ, growth in situ demands blood or something equivalent, and probably something equivalent to nerves too. The problem of supplying a freely rotating organ with blood vessels (not to mention nerves) that don't tie themselves in knots is too vivid to need spelling out. There might be a solution, but we need not be surprised that it has not been found. Human engineers might suggest running concentric ducts to carry blood through the middle of the axle into the middle of the wheel. But what would the evolutionary intermediates have looked like? Evolutionary improvement is like climbing a mountain. You can't jump from the bottom of a cliff to the top in a single leap. Sudden, precipitous change is an option for engineers, but in nature the summit of the evolutionary mountain can be reached only via a gradual ramp upwards from the starting point. The wheel may be one of those cases where the engineering solution can be seen in plain view, yet be unattainable in evolution because it lies on the other side of a deep valley: unevolvable by large animals but within the reach of bacteria because of their small size. ... Bacteria were able to evolve the wheel because the world of the very small is so very different and presents such different technical problems." (Dawkins, 2004, pp.547-549)

[That there are biophysical reasons why "large animals" don't have wheels is irrelevant, and a fallacy of false alternatives, since there are "very small" animals like nematodes and protozoans, which don't even have "blood" and none of them have wheels either. Dawkins admits the problem of "evolutionary intermediates" to a wheel, but does not explain how these intermediates would be "within the reach of bacteria because of their small size." As Haldane pointed out above, "the wheel" irrespective of its size "would be useless till fairly perfect," and bacteria especially could not be expected to accumulate the components of a future flagellar motor in anticipation of their being useful when all are present, let alone then assemble them into a motor!]

"As it happens, the bacterial flagellar motor itself has recently, in the hands of a species of creationists who call themselves `Intelligent Design Theorists'; been elevated to the status of icon of alleged unevolvability. Since it manifestly exists, the conclusion of their argument is different. Whereas I proposed unevolvability as an explanation for why large animals like mammals don't grow wheels, creationists have seized upon the bacterial flagellar wheel as something that cannot exist and yet does - so it must have come about by supernatural means!" (Dawkins, 2004, pp.549-550)

[The "creationist" (so-called) that Dawkins is talking about is professor Michael Behe, who (as Dawkins would be well aware) distances himself from "creationism,", accepts that "the universe is the billions of years old," and that "all organisms share a common ancestor":

"Evolution is a controversial topic, so it is necessary to address a few basic questions at the beginning of the book. Many people think that questioning Darwinian evolution must be equivalent to espousing creationism. As commonly understood, creationism involves belief in an earth formed only about ten thousand years ago, an interpretation of the Bible that is still very popular. For the record, I have no reason to doubt that the universe is the billions of years old that physicists say it is. Further, I find the idea of common descent (that all organisms share a common ancestor) fairly convincing, and have no particular reason to doubt it." (Behe M.J., "Darwin's Black Box: The Biochemical Challenge to Evolution," Free Press: New York NY, 1996, pp.5-6)
Moreover, as a Roman Catholic, Behe's problem with evolution is not religious, but scientific:
"As a Catholic, Behe was taught that evolution could be viewed as God's way of creating. What forced Behe to change his mind about the truth of Darwinism and to propose intelligent design was not religion, but scientific discoveries in his own field. ... For his doctoral studies, Behe moved across town to the University of Pennsylvania. There he plugged away for four years and, after completing his Ph.D. in biochemistry in 1978, attained an appointment to the National Institutes of Health in Bethesda, Maryland. One of his colleagues in the genetics laboratory at the National Institutes of Health was a fellow Catholic biochemist, Jo Ann Nichols. Rarely did their work touch on evolution, but Behe recalls one day when the issue did arise, as a matter of joint speculation between them during a break. The question was this: `If the first life did arise by random naturalistic processes from a chemical soup, as all textbooks are saying, what exactly are the minimum systems that are required for life?' Together they ticked off a mental list of the minimum requirements: a functioning membrane, a system to build the DNA units, a system to control the copying of DNA, a system for energy processing. Suddenly, they broke off their speculation, looked at each other, and smiled, jointly muttering, `Naaah--too many systems; it couldn't have happened by chance.'" (Woodward T., "Meeting Darwin's Wager," Part 2 of 3, Christianity Today, April 28, 1997).

"This is the ancient `Argument from Design; also called the `Argument from Paley's Watchmaker', or the `Argument from Irreducible Complexity.' I have less kindly called it the `Argument from Personal Incredulity' because it always has the form: `I personally cannot imagine a natural sequence of events whereby X could have come about. Therefore it must have come about by supernatural means: Time and again scientists have retorted that if you make this argument, it says less about nature than about the poverty of your imagination. The `Argument from Personal Incredulity' would lead us to invoke the supernatural every time we see a good conjuror whose tricks we cannot fathom." (Dawkins, 2004, p.549)

[This time Dawkins employs the fallacy of erecting a straw man. The "Argument from Irreducible Complexity" (IC) is not of "the form: `I personally cannot imagine a natural sequence of events whereby X could have come about. Therefore it must have come about by supernatural means.'" Rather, IC is based on what science itself has revealed about the enormous complexity of life's molecular machines and the limitations of unintelligent natural causes in adequately explaining them:

"From observable features of the natural world, intelligent design infers to an intelligence responsible for those features. The world contains events, objects and structures that exhaust the explanatory resources of undirected natural causes and that can be adequately explained only by recourse to intelligent causes. This is not an argument from ignorance. Nor is this a matter of personal incredulity. Precisely because of what we know about undirected natural causes and their limitations, science is now in a position to demonstrate design rigorously." (Dembski W.A., "Intelligent Design: The Bridge Between Science and Theology," InterVarsity Press: Downers Grove IL., 1999, p.107)

In the 1984 book on the origin of life which is usually credited with starting the modern ID movement, Thaxton, et al. pointed out that "the sharp edge of this critique is not what we do not know, but what we do know. ... The advance of science itself is what is challenging the nation that life arose on earth by spontaneous ... chemical reactions":
"One characteristic feature of the above critique needs to be emphasized. We have not simply picked out a number of details within chemical evolution theory that are weak, or without adequate explanation for the moment. For the most part this critique is based on crucial weaknesses intrinsic to the theory itself. Often it is contended that criticism focuses on present ignorance `Give us more time to solve the problems,' is the plea. After all, the pursuit of abiogenesis is young as a scientific enterprise. It will be claimed that many of these problems are mere state-of-the-art gaps. And, surely some of them are. Notice, however, that the sharp edge of this critique is not what we do not know, but what we do know. Many facts have come to light in the past three decades of experimental inquiry into life's beginning. With each passing year the criticism has gotten stronger. The advance of science itself is what is challenging the nation that life arose on earth by spontaneous (in a thermodynamic sense) chemical reactions." (Thaxton C.B., Bradley W.L. & Olsen R.L., "The Mystery of Life's Origin: Reassessing Current Theories," [1984], Lewis & Stanley: Dallas TX, 1992, Second Printing, p.185. Emphasis original)
Moreover, there is an important qualification to the argument from ignorance, and that is "if a certain event had occurred, evidence for it would have been discovered by qualified investigators" in which "case it is perfectly reasonable to take the absence of proof of its occurrence as positive proof of its nonoccurrence," because it "is not based on ignorance but on our knowledge that if it had occurred it would be known" (my emphasis):
"Argumentum ad Ignorantiam (argument from ignorance) The fallacy of argumentum ad ignorantiam ... is committed whenever it is argued that a proposition is true simply on the basis that it has not been proved false, or that it is false because it has not been proved true. But our ignorance of how to prove or disprove a proposition clearly does not establish either the truth or the falsehood of that proposition. ... A qualification should be made at this point. In some circumstances it can safely be assumed that if a certain event had occurred, evidence for it would have been discovered by qualified investigators. In such a case it is perfectly reasonable to take the absence of proof of its occurrence as positive proof of its nonoccurrence. Of course, the proof here is not based on ignorance but on our knowledge that if it had occurred it would be known. For example, if a serious security investigation fails to unearth any evidence that Mr. X is a foreign agent, it would be wrong to conclude that their research has left us ignorant. It has rather established that Mr. X is not one. Failure to draw such conclusions is the other side of the bad coin of innuendo, as when one says of a man that there is `no proof' that he is a scoundrel. In some cases not to draw a conclusion is as much a breach of correct reasoning as it would be to draw a mistaken conclusion." (Copi I.M., Introduction to Logic," [1953], Macmillan: New York, Seventh Edition, 1986, pp.94-95)

`True believing' Darwinists like Dawkins might like to think they have forever to provide a plausible fully naturalistic explanation of molecular machines like the bacterial flagellar motor, but they don't. The longer the Darwinists fail to deliver the naturalistic goods, the more the general public (which ultimately funds most science through their taxes, and is the parents of the next generation of scientists), will lose faith that there is a naturalistic explanation and turn to intelligent design for an explanation!

And as we shall see, Dawkins actually conceded that, "It is perfectly legitimate to propose the argument from irreducible complexity as a possible explanation ..." and "it is possible to imagine validly using some version of the argument from design, or the argument from irreducible complexity ..."!]

To be continued in part #2.

Stephen E. Jones, BSc (Biol).
"Problems of Evolution"

4 comments:

Tony Cox said...

Thank you for taking the time to compile this blog. I am enlightened and now encouraged to read your other postings. Well done sir!

Stephen E. Jones said...

Tony

>Thank you for taking the time to compile this blog. I am enlightened and now encouraged to read your other postings. Well done sir!

Thanks. There is a lot to read in my 500+ postings on this blog from 2005.

But I have taken a `sabbatical leave' from Creation/Evolution/Design and am now mainly posting on my other two blogs: "Jesus is Jehovah!" and "The Shroud of Turin."

Stephen E. Jones

Henry R. said...

There is a different type of bacteria, (type three secretory) the one thought to be responsible for transmitting the bubonic plague and other viruses, Which has many but not all of the compositions found in the flagellum's rotary system but instead this bacteria used the filament to inject, kind of like a microscopic syringe, and therefore it does not rotate it's filament but it still serves a useful purpose. The two bacteria are undeniably related. Therefore it is undeniable proof that flagellum among all other organisms evolved from a less complex organism.

Stephen E. Jones said...

Henry R.

>There is a different type of bacteria, (type three secretory) ... Which has many but not all of the compositions found in the flagellum's rotary system ... The two bacteria are undeniably related.

Thank you for your comment. I have answered it in a separate post.

Stephen