Darwin’s Black Box: The Biochemical Challenge to Evolution

Michael J. Behe | Saturday, April 30, 2005
Copyright © 2005, Michael J. Behe

Professor of Biochemistry, Lehigh University

Edited transcript from a lecture given Friday, April 29, 2005, 6:30 and 8:15 p.m. 194 Chemistry, University of California, Davis As part of the Faith and Reason series sponsored by Grace Alive! and Grace Valley Christian Center

The topic of my talk is the argument for intelligent design in biology. There have been many arguments put forth for intelligent design in aspects of the physical world, like the mind, physical laws, anthropic coincidences, and the like. But the argument for intelligent design in biology has only come forward more recently, perhaps in the past ten years. It seems to be getting a lot of attention today in the media and elsewhere, including academic outlets. For example, there was a book published a year or so ago called Darwinism, Design, and Public Education, (J.A. Campbell and S.C. Meyer, eds., Michigan State Univ Press, 2003) addressing the question of what public schools should teach on the topic of where life came from. Another book, God and Design: The Teleological Argument and Modern Science, (N.A. Manson, ed., New York: Routledge Press, 2003) addresses the question: Is there design in the world? A large segment of that book is given over to the topic of intelligent design in biology. I have written chapters in both of these books.

The best book for someone interested in the topic of design in biology is one published by Cambridge University Press in 2004 called Debating Design: From Darwin to DNA, edited by William Dembski, an advocate of intelligent design, and Michael Ruse, a philosopher of biology and a prominent Darwinist. The attractive thing about this book is that it represents a wide distribution of viewpoints all between the covers of one book. There are intelligent design advocates like myself; there are Darwinian biologists arguing for their viewpoint; there are “complexity theorists’ who disagree with both of the first points of view; and there are “theistic evolutionists,’ who give still another point of view. If anyone wants to see where this discussion is going, this book is a great place to start.

Another outlet that the intelligent design argument has found is in the more general media, including the New York Times, perhaps because of current debates going on among school boards about whether or not to talk about intelligent design in their curricula. About two months ago I was invited to contribute an op-ed piece (M.J. Behe, Design for Living, The New York Times, Feb. 7, 2005), essentially just laying out what intelligent design is in biology, because there seems to be a lot of confusion in this debate.

Outline of Design Argument

In this lecture I will essentially follow the outline of my op-ed piece and present what I see to be the argument for intelligent design in biology. It is really a pretty simple one with five separate components:

1. Design is not mystical; it is deduced from the physical structure of a system. The first point is that design is not a mystical conclusion. It is not something that we have to close our eyes and raise our hands and say, “Oh, yes, now I see the design.’ It can be deduced simply from the physical structure of a system. In the same way that we make other logical conclusions, we can conclude design just from the physical evidence.

2. Everyone agrees that aspects of biology appear to be designed. Even those who disagree with the design argument, including the most convinced Darwinian biologists, agree that aspects of biology appear to be designed.

3. There are structural obstacles to Darwinian evolution. The proposed alternative to actual design, Darwinian evolution, has structural obstacles that hinder its use as an explanation.

4. Grand Darwinian claims rest on undisciplined imagination. Darwinian evolution can explain some things, but the grand claims that it can explain the deep structure of life rest on an undisciplined imagination. People think it is a valid explanation, but if we look for the facts behind it, we come up empty.

5. Bottom line: We have strong evidence for design, but only conjecture and little evidence for Darwinism.

I. Design is Deduced

Design is not a fuzzy, mystical conclusion we come to; it is a simple deduction based on the physical structure of a system. To demonstrate, suppose someone showed you a picture of the Sawtooth Mountains in Idaho and asked, “Where did these mountains come from?’ You might say, “I don’t know; I’m not a geology major. Plate tectonics, I suppose, or volcanic activity, or maybe erosion or something like that.’ And he says, “Okay, but why is this point a little bit higher than that one, and this peak is half a mile from that one?’ You would say, “I don’t know. A mountain has to look like something!’ And most people would be satisfied with that response.

But suppose someone showed you a picture of Mount Rushmore in South Dakota. Would you say, “Well, it’s got to look like something’? Yes, plate tectonics and volcanic activity are clearly part of what gave rise to this mountain. But it is also clear that intelligence was involved in shaping some aspects of it. So when we ask, “Well how did this piece of the mountain (Washington’s eyebrow) come to be at this specific angle to this one (Washington’s nose)?’ or “How did this point happen to be six feet behind this one, giving the impression of an eye?’ those details become very important. What is more, it is from details such as this, and the fact that they match a pattern external to the forces that usually shape mountains, that we detect design. We detect it from the physical properties of the system, not from mystical, fuzzy thinking. It is a simple deduction.

II. Appearance of Design

The next point is that things like Mount Rushmore show up in biology also. There are aspects of biology that everyone agrees do in fact appear to be designed. Even those who are not convinced of the design argument will agree with this. For example, Francis Crick, the Nobel laureate and co-discoverer of the structure of DNA along with James Watson, once wrote: “Biologists must constantly keep in mind that what they see was not designed, but rather evolved’ (Francis Crick, What Mad Pursuit: A Personal View of Scientific Discovery [New York: Basic Books, 1988] 138). Why do they have to strain so hard to remember that what they see in biology was not designed? Clearly, because what they see does look like it was designed.

David DeRosier, who works on a biological system called the bacterial flagellum, has remarked, “More so than other motors, the flagellum resembles a machine designed by a human’ (D.J. DeRosier, The Turn of the Screw: The Bacterial Flagellar Motor, 1998, Cell, Vol. 93, p.17-20). He obviously looked at this system and said that it looks like machinery that intelligent agents make.

Perhaps the most prominent popularizer of Darwinian biology today is Richard Dawkins, professor of biology at Oxford University in England. Even he agrees with this idea of design in biology. His book, The Blind Watchmaker (New York: Norton, 1986), is a vigorous defense of Darwinian evolution. Nonetheless, on the first page of the first chapter, he writes, “Biology is the study of complicated things that give theappearance of having been designed for a purpose‘ (Dawkins, p. 1, italics added). Dawkins is saying that, like Mount Rushmore, these things look designed from their physical structures. Of course, his book is really a defense of Darwinism, so Dawkins does not think that there is real design; he says there is just an appearance of it. He thinks that, rather than actual design, natural selection explains what we perceive as design. Nonetheless, he also insists that biology reeks of design. He says, “Natural selection is the blind watchmaker, blind because it does not see ahead, does not plan consequences, has no purpose in view. Yet the living results of natural selection overwhelmingly impress us with the appearance of design as if by a master watchmaker, impress us with the illusion of design and planning’ (Dawkins, p. 21, italics added). My point here is that even Dawkins thinks the appearance of design is overwhelming.

We can perceive design from the physical parts of the system we are looking at. Dawkins writes further, “We may say that a living body or organ is well designed if it has attributes that an intelligent and knowledgeable engineer might have built into it in order to achieve some sensible purpose, such as flying, swimming, seeing. . .’ (Dawkins, p. 21, italics added). In other words, if we see attributes that match a function, it suggests design. Then he goes on to say that the design does not have to be perfect: “It is not necessary to suppose that the design of a body or organ is the best that an engineer could conceive of . . . But any engineer can recognize an object that has been designed, even poorly designed, for a purpose, and he can usually work out what that purpose is just by looking at the structure of the object’ (Dawkins, p. 21). Once more, he is saying that design can be perceived from the physical attributes of the system.

In his argument, Richard Dawkins is echoing the design argument of William Paley, who lived in the early 1800s. Paley wrote a book called Natural Theology, in which he essentially said that biology exudes design. Paley concluded that there was real design; to illustrate, he gave the example of how one could clearly see the design in a watch. Dawkins’ book is named after Paley’s argument. So Dawkins is saying, “Yes, Paley correctly identified this problem, but he thought there was a real watchmaker. In reality, natural selection is the blind watchmaker.’ That is how Dawkins solves the problem.

Nonetheless, William Paley stated the problem in the following way: “When we come to inspect the watch, we perceive . . . that its several parts are framed and put together for a purpose, e.g. that they are so formed and adjusted so as to produce motion, and that motion so regulated as to point out the hour of the day; . . . The inference we think is inevitable, that the watch must have had a maker’ (William Paley, Natural Theology, 1802, chapter 1). Paley argued that when we see all these parts put together into a complex entity that produces a recognizable function, we must be overwhelmed with the idea that this must have been designed.

Modern science has discovered that life has an overwhelmingly greater resemblance to mechanically designed systems than even William Paley thought. As we discovered the molecular foundation of life, the resemblance of life to intricate machines like a watch has become much stronger. For example, in 1998 the journalCell published a special review issue on macromolecular machines, which are, literally, machines made of molecules. It has been discovered that the very foundation of life is, in fact, run by machines. In the artist’s illustration on the cover, there is an object in the lower left hand corner evocative of the watch that Paley had talked about. The table of contents lists articles such as, “The Cell as a Collection of Protein Machines,’ “Polymerases and the Replisome: Machines within Machines,’ “Mechanical Devices of the Spliceosome: Motors, Clocks, Springs and Things.’

The editor of this special issue was Bruce Alberts, president of the National Academy of Sciences and professor of biochemistry at the University of California, San Francisco. In his introduction, he wrote, “We have always underestimated cells. Undoubtedly we still do today. But at least we are no longer as naïve as we were when I was a graduate student in the 1960s. . . . The chemistry that makes life possible is much more elaborate and sophisticated than anything we students had ever considered. . . . Indeed, the entire cell can be viewed as a factory that contains an elaborate network of interlocking assembly lines, each of which is composed of a set of large protein machines‘ (B.A. Alberts, The Cell as a Collection of Protein Machines. Cell, Vol. 93, 291-294).

Alberts emphasized that this word “machines’ is not an analogy, but is meant literally. He wrote, “Why do we call the large protein assemblies that underlie cell function protein machines? Precisely because, like the machines invented by humans to deal efficiently with the macroscopic world, these protein assemblies contain highly coordinated moving parts’ (Alberts, p. 291-294). The point is that we can perceive design in the physical attributes of a system, and that the more science discovers about life, the more we see the resemblance of life to sophisticated machinery like watches.

III. Structural Obstacles to Darwinian Evolution

Clearly, then, we can say that everyone agrees that some aspects of biology appear to be designed. But neither Bruce Alberts nor Richard Dawkins really thinks that life is designed. They think that natural selection explains what we have discovered in the cell. So my next point is that there are structural obstacles to Darwinian evolution that are little appreciated and would preclude this explanation.

In his book, On the Origin of Species, Charles Darwin discussed the eye in a section entitled “Organs of Extreme Perfection and Complication.’ He wrote, “If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case’ (Charles Darwin, On the Origin of Species, p. 158).

In this passage, Darwin was emphasizing that his theory was a gradual one. He knew that natural selection had to improve life slowly, in tiny steps over long periods of time. He knew that if things appeared to improve rapidly, in large leaps, then it would begin to look suspiciously like there was something other than random mutation and natural selection going on. So Darwin always insisted that his theory of evolution had to explain gradual pathways to biological systems as we know them.

Let us take Darwin at his word and ask: What sort of an organ or system looks like it would be difficult to put together by numerous, successive, slight modifications? Such a system is one that is irreducibly complex or has the property of irreducible complexity. That is an elaborate phrase standing for a simple concept. Irreducible complexity means that there is a system with a number of parts that interact with each other. This interaction produces a function that the individual components do not produce on their own, and if we take even one part away, the system will break down.

We can understand this concept by looking at an example of an irreducibly complex system found in our everyday world: the mousetrap. A mousetrap has a number of different parts. First, it has a wooden platform to which everything else is attached. It has a tightly wound metal spring with extended ends to push against the platform at one end, and another extended end to push against the hammer, which actually squashes the mouse. When we push the hammer over, it has to be stabilized in position until the mouse comes along. That is the job of the holding bar. The end of the bar has to be inserted into the catch in order to stabilize it until the mouse comes along.

The mousetrap needs all of these parts to work. If we take away the holding bar, the spring, or the catch, we do not have a mousetrap that may work half as well as it used to or a quarter as well. No, we have a broken mousetrap that does not work at all. This is what we mean by irreducible complexity-the trap needs all of its parts to work.

Such irreducibly complex systems are problems for Darwin’s theory, because if we wanted to put together something like a mousetrap by a Darwinian process, how would we start? Would we start with maybe just the platform itself and maybe hope to catch mice perhaps by tripping them? Could we then add the holding bar, hoping that as the mouse trips, it will impale itself on the bar? No, we cannot do that, because, with irreducibly complex systems, the function does not appear until we have essentially put the whole thing together. So the problem is that natural selection would have nothing to select. There is nothing working, nothing catching mice, until we have the whole system put together. Then there is nothing left for natural selection to do because the system has already been compiled.

Mousetraps are very interesting, and I think about them a lot. But what we really want to know is: Are there any irreducibly complex biological systems, cellular systems, biochemical or molecular systems? The answer is, yes, there are tons of them. They are all over the place; in fact, it is hard to avoid them.

One example is the bacterial flagellum. There is an excellent drawing of the bacterial flagellum in a popular biochemistry textbook by Voet & Voet (Biochemistry, 1995) that is used at many universities. The flagellum is, quite literally, an outboard motor that enables bacteria to swim. Just like a regular outboard motor, it has a rotary engine that spins a propeller around and around. When the part that acts as a propeller spins, it pushes against the liquid medium in which the bacteria is and pushes the cell forward. The propeller is attached to the drive shaft by the hook region, which acts as a universal joint, allowing freedom of rotation. The drive shaft is attached to the motor, which uses a flow of acid from the outside of the cell to the inside to power the motor, just like a waterfall might power the turning of a turbine. The whole apparatus has to be kept stationary in the plane of the membrane as the propeller turns, just like a real outboard motor has to be clamped onto a boat while the propeller is turning. That is the job of some proteins which act as stators. The drive shaft has to poke up through a couple of membranes in the bacterium, and there are proteins that act as bushing material, allowing the drive shaft to pass through.

I know this appears complex, but it is actually a very simplified description of the flagellum. In the past thirty years or so research has shown that there are thirty to forty separate protein parts required for this system to function. In the absence of most of them-for example, in the absence of the hook or the propeller or the drive shaft-we don’t get a flagellum that spins half as fast as it used to or a quarter as fast: we have a broken flagellum. Or, more likely, we don’t have a flagellum at all, because the cell also has sophisticated feedback systems to tell it when the construction of this rather large apparatus is going well. If it isn’t, the cell shuts off synthesis in order to save energy.

Thus, much like the mousetrap, the flagellum is irreducibly complex. It has a number of different parts that produce the function, and if the parts are missing, the system no longer works. And much like the mousetrap, its gradual evolutionary production by numerous, successive, slight modifications is very, very difficult to envision.

I like to show pictures of the flagellum, because most people can quickly grasp that it is not like a machine; it is a machine. It is not analogous to a machine; it is a real molecular machine, and perhaps that can give us some insight into where it came from.

When I say that I am skeptical that Darwinian processes produced the flagellum, I am not really saying anything too controversial. There are actually a number of scientists who also have looked at the flagellum and other complex molecular systems in the cell and said they do not think that Darwin’s gradual mechanism of natural selection can account for these things-people like Stuart Kaufman at the University of Calgary, Lynn Margulis at the University of Massachusetts, and James Shapiro at the University of Chicago. A number of scientists have said that a gradual pathway does not seem to adequately explain things like this.

Where I differ from other skeptics of Darwinian evolution, however, is in the alternative I have proposed to explain where something like this did come from. Flagellum or other complex biochemical machines look like they were designed purposely by an intelligent agent. Making such statements has gotten a bit of attention. Some of my critics have said, “This Behe fellow is an admitted Christian. He has been seen entering and leaving churches. Therefore, this idea of design must be a religious idea, not a scientific one. He is letting his religious beliefs interfere with his scientific work.’ I appreciate their concern, but I disagree with them. I think the conclusion of design is a completely empirical one. (GVCC) By that I mean that we can perceive design strictly from the physical structure of the system, just as we do with Mount Rushmore, along with an understanding of what it takes to come to the logical conclusion of design.

How can we do this? How do we perceive that something is designed? In fact, we do it every day. We may walk down the street and look to our left and say, “Oh, isn’t it pretty how someone arranged those flowers!’ Then we look to our right and say, “Look how the wind blew that trash over there.’ How can we perceive design? There is actually a lot to say about it, and we do not have time to go into it right now. But I think a large chunk of it is captured in a cartoon from Gary Larson’s The Far Side.

In one particular Far Side cartoon, we see a troupe of jungle explorers in a line. The lead explorer has been strung up by a vine and skewered by two apposing three-pronged bamboo forks. The third fellow in line turns to the fellow behind him and says, “That’s why I never walk in front.’ Now, everyone who sees this cartoon will immediately realize that this event was designed; his death was intended, not accidental. As a matter of fact, the humor of the cartoon depends on us recognizing the design. But how do we know that this was designed? Is it a religious conclusion? Probably not. We know it because we see a number of different parts interacting with each other to produce a function that the parts by themselves could not produce. Essentially, this demonstrates something of what we mean by “irreducible complexity.’ As I said, there is a lot more to be said about it, but this captures a big chunk of how we go about recognizing design.

Thus, there are structural obstacles to Darwinian evolution, and irreducible complexity is the main one.

IV. Grand Darwinian Claims Rest on an Undisciplined Imagination

The next argument is that, despite what modern science asserts, Darwinian claims rest more on imagination than on data. The ability of Darwinian processes to explain what seems to be design is not very convincing. What do I mean by “undisciplined imagination’? Imagination is a good thing in science, but we must keep in touch with reality. If we don’t, we might come up with things that really cannot happen. In other words, imagination must be grounded in facts. Many Darwinian stories about how life came about have lost touch with the data.

My book, Darwin’s Black Box (New York: The Free Press, 1996), spells out the arguments that I am skimming over in this lecture. The argument is not difficult to see; it is pretty straightforward. Nonetheless, when my book was published, it seemed to catch many people by surprise, and thus has received a fair amount of attention. It has been widely reviewed, for example, by the New York Times, theWashington Post, Nature, American Scientist, Boston Review, and many other publications. It has also been reviewed by overseas press, including Aboardmagazine, the in-flight magazine of the Bolivian national airlines. Christianity Todaynamed it “Book of the Year.’

Reviewers have included a number of scientists, including chemists like myself, molecular biologists, and evolutionary biologists. I want to give you a sample of what they had to say:

• James Shreeve, science writer for the New York Times, said, “Mr. Behe may be right that given our current state of knowledge, good old Darwinian evolution cannot explain the origin of blood clotting or cellular transport.’

• James Shapiro, professor of microbiology at the University of Chicago, wrote in National Review, “There are no detailed Darwinian accounts for the evolution of any fundamental biochemical or cellular system, only a variety of wishful speculations.’

• Jerry Coyne, a professor of evolutionary biology at the University of Chicago, wrote in Nature, the most prominent science journal in the world, “There is no doubt that the pathways described by Behe are dauntingly complex, and their evolution will be hard to unravel. . . .We may forever be unable to envisage the first protopathways.’

• Andrew Pomiankowski wrote in New Scientist, “Pick up any biochemistry textbook, and you will find perhaps two or three references to evolution. Turn to one of these and you will be lucky to find anything better than ‘evolution selects the fittest molecules for their biological function.”

My point is that everyone agrees that the pathways I described have not been explained in Darwinian terms. Someone else who speaks about this is David Griffin, professor of the philosophy of religion at Claremont College in California. Griffin is not an adherent of intelligent design, but in a book published a few years ago he said that he had asked people about my claim that there are no explanations for these molecular machines. Then he wrote, “The response I have received from repeating Behe’s claim about the evolutionary literature-which simply brings out the point being made implicitly by many others, such as Crick, Denton, Shapiro, Stanley, Taylor, Wesson-is that I obviously have not read the right books. There are, I am assured, evolutionists who have described how the transitions in question could have occurred.’ And he goes on to say, “When I ask in which books I can find these discussions, however, I either get no answer or else some titles that, upon examination, do not in fact contain the promised accounts. That such accounts exist seems to be something that is widely known, but I have yet to encounter anyone who knows where they exist’ (D.R. Griffin, Religion and Scientific Naturalism, [SUNY Press, 2000] 287). Essentially he seems to be saying that it is an urban legend that Darwinian theory has explained these things. In fact, it is just that: we have the idea that someone knows these accounts exist, but when we look for them, we cannot find them.

The general reaction by scientists to my argument is best summarized in The Way of the Cell, written by Franklin Harold, an emeritus professor of biochemistry at Colorado State University. He wrote that, when considering the argument for intelligent design, “We should reject, as a matter of principle, the substitution of intelligent design for the dialogue of chance and necessity (Behe 1996); but we must concede that there are presently no detailed Darwinian accounts of the evolution of any biochemical system, only a variety of wishful speculations’ (Franklin Harold, The Way of the Cell, [New York: Oxford University Press, 2001] p. 205, italics added).

Let’s take a minute to consider the two points that Franklin Harold makes here. We will consider them in reverse order. He said that there are no detailed Darwinian accounts, only wishful speculations, or what is more colloquially known as “Just So Stories,’ named after the children’s stories written by Rudyard Kipling over a hundred years ago: “How the Tiger Got Its Stripes,’ “How the Rhinoceros Got Its Horn,’ “How the Bacterium Got Its Flagellum.’ We may speak humorously, but if we think seriously, it is astounding that a theory that has been so utterly fruitless in explaining the very foundation of life seems to command the majority support of biologists. It makes us think that perhaps maybe another explanation might be called for.

Franklin Harold’s other point is that there is some principle that forbids us from entertaining the idea of intelligent design. What principle is that? After all, if we look at the drawing of the bacterial flagellum, the idea of design pops into our heads right away. Harold does not actually say what the principle is. He just wrote what is quoted above, and then went on to other things in his book. But I think the principle that he had in mind is best illustrated by a Ghostbusters symbol: No supernatural beings allowed!

The idea of intelligent design strongly seems to point beyond nature. It seems to have philosophical and maybe even theological implications. That makes some people very nervous. They think that science should avoid ideas that have strong extra-scientific implications. Again, I understand their concern, but I disagree with them.

When I was being trained as a scientist, we were always told that science is supposed to follow the evidence, wherever it leads, and let other people worry about the philosophical or other implications. I thought that was good advice then, and I think it continues to be good advice. So I disagree with Harold’s “principle.’

Design and Blood Clotting

These have been some of the general reactions to the argument I presented inDarwin’s Black Box for intelligent design. There have also been some specific objections to my argument. In the remainder of my talk, I would like to discuss one that I think is particularly illuminating: the blood clotting system.

In our day-to-day lives, no one gives our blood clotting system much thought. On a macroscopic level, when a man shaves and nicks himself, a little blood may trickle out and flow down, then stop and heal over. It seems simple. But research done in the past several decades has shown that the system that controls clotting is enormously complex and includes dozens of different protein parts. It has to be complex because it has to be very precise. Blood has to clot just exactly where and exactly when it is needed. If it clots at the wrong time or in the wrong place, we can have a heart attack or stroke. So the system that causes blood to clot is very complex. A schematic of the clotting cascade system can be found in any college-level biochemistry textbook.

Fibrin, the meshwork of the blood clot itself, cannot exist as the meshwork clot in our blood, or else all of our blood would be clotted and we would be dead. Instead, fibrin exists as an inactive precursor called fibrinogen, which is soluble and floats around in the bloodstream. When a clot has to form, a piece of the fibrinogen is cut off of it, exposing a specific sticking site that interacts with other activated fibrin molecules and allows them to stick to each other and make this meshwork clot. The protein that does that is called thrombin.

But thrombin cannot exist in its active form, or it would immediately cut off the piece of fibrinogen, turning it into fibrin, and again we would be dead. So thrombin exists as an inactive precursor, called prothrombin, which has to be activated by another protein. That protein also has to exist as an inactive precursor, which is activated by another one that is inactive, which is activated by another one. This system is called a cascade, because one factor activates another factor, that activates another, and so on.

I wrote about the blood clotting system in Darwin’s Black Box, arguing that it was irreducibly complex and, therefore, had to have been designed. A man named Russell Doolittle disagreed with me, writing about it in an article called “A Delicate Balance’ in the Boston Review, published by the Massachusetts Institute of Technology. That was not good for me, because Russell Doolittle is a prominent biochemist, a professor of biochemistry at the University of California, San Diego. A member of the National Academy of Sciences, he has worked on the blood clotting system for the past forty years. So he is not the kind of person we would want on the other side. Doolittle wrote in his essay that not only is the idea of irreducible complexity wrong, but there is experimental evidence demonstrating that it is wrong:

“Recently the gene for plasminogen was knocked out of mice [that means rendered inactive], and, predictably, those mice had thrombotic complications because fibrin clots could not be cleared away.’ Plasminogen is like molecular scissors that chops up and removes blood clots once their work has been done. If we cannot remove them, the clots stay around and our circulatory system gets clogged up, resulting in problems. Doolittle continued, “Not long after that, the same workers knocked out the gene for fibrinogen in another line of mice.’ Fibrinogen is the precursor of the clot material itself. “Again, predictably, these mice were ailing, although in this case their problem was hemorrhage was the problem. And what do you think happened when these two lines of mice were crossed? For all practical purposes, the mice lacking both genes were normal! Contrary to claims about irreducible complexity, the entire ensemble of proteins is not needed. Music and harmony can arise from a smaller orchestra’ (R. Doolittle, “A Delicate Balance,’ Boston Review, Feb/March 1997, pp. 28-29).

Doolittle’s point was that if we knocked out one component of the cascade in this one line of mice, they would have problems. If we knocked out a different component in another line of mice, they would have different problems. But if we mix them together, breeding a line of mice missing both components, they are normal. Thus, evolution apparently would not have to produce all twenty proteins at once; maybe it could proceed in steps of two proteins, or something like that. Doolittle actually does not spell out his argument, but we do not really have to think too much about what he said, because it turns out that he was wrong. He misread the paper that he was describing. The double knock-out mice do not have a functioning clotting system.

The paper Doolittle was referring to, “Loss of Fibrinogen Rescues Mice from the Pleiotropic Effects of Plasminogen Deficiency,’ was published in the journal Cell. Russell Doolittle saw the phrase “Rescues Mice’ and thought the mice were normal. It turns out they were not. As the researchers themselves wrote in the abstract, “Mice deficient in plasminogen and fibrinogen are phenotypically indistinguishable from fibrinogen-deficient mice’ (Bugge, T.H., et al. Loss of Fibrinogen Rescues Mice. . .Cell, 1996, Vol. 87, pp.709-715). That means that mice missing both components have all the problems that mice missing only fibrinogen have. Their blood does not clot. They hemorrhage. Female mice die during pregnancy. They are not promising evolutionary intermediates.

A table of the symptoms of the different lines of mice shows that mice lacking plasminogen have this suite of symptoms: thrombosis, ulcers, and high mortality. Lacking fibrinogen they have this suite of symptoms: no clotting, hemorrhage, death during pregnancy. Lacking both, they have been “rescued’ from the symptoms of plasminogen deficiency, only to suffer all the symptoms of fibrinogen deficiency. Now if we think about this for just a moment, we can see what is going on. Plasminogen removes blood clots after their work has been done, and if we do not have that, blood clots stick around, clog things up, and we have got problems. Mice missing fibrinogen cannot form clots at all, so they cannot clot; rather, they hemorrhage. So if they do not have either one, it does not matter if they do not have plasminogen: they cannot form clots in the first place, so the clots do not have to be removed! The blood clotting system will still not work, and the mice will be in big trouble.

The same workers have gone on to knock out a couple other components of the blood clotting cascade-prothrombin and tissue factor. In each case, the blood clotting system was also broken and the mice were in big trouble. This is exactly what we would predict if the system were indeed irreducibly complex, as I have argued.

What can we conclude from Russell Doolittle’s mistake? It is not that he misread a paper. Anyone can do that. It took me a couple of readings to figure out what the writers were trying to say (scientists are not known for the clarity of their prose). But the point is, when it comes to the blood clotting system, Russell Doolittle probably knows more about blood clotting and the proteins of the cascade and their gene structure than anyone else on earth. Yet we can see from this mistake that even Russell Doolittle does not know how Darwinian processes could put together a complex system like the blood clotting cascade. If he did, he would have simply told us in the article or cited some papers where it had been explained. Instead, he cited a paper that talked about hemorrhaging mice. My point is that if Russell Doolittle does not know how Darwinian evolution could produce the blood clotting system, no one knows. That is an important point to keep in mind.

These examples serve to illustrate why I believe that Darwinian claims rest on imagination, rather than experimentation, data, and evidence.

V. The Bottom Line

The bottom line is that there is strong evidence for design and little for Darwinism. We just looked at the little evidence for Darwinism in the last few slides. But what is that strong evidence for design? “The living results of natural selection overwhelmingly impress us with the appearance of design as if by a master watchmaker, impress us with the illusion of design and planning’ (Richard Dawkins,The Blind Watchmaker [New York: Norton, 1986] 21). It is what we see and have discovered in life-that is, in fact, the evidence of design.

What sort of an argument is it to say that when we look at something like Mount Rushmore, we perceive a design from the interaction of its parts? Humorously, it is called “in-duck-tive’ reasoning-i.e., if it looks like a duck, walks like a duck, and quacks like a duck, we are justified in concluding that it is indeed a duck!

This is the colloquial expression of a serious argument today. Philosophers call this kind of an argument an inductive argument. When we use a number of established facts to draw a general conclusion, we are using inductive reasoning. TheEncyclopedia Britannica, as well as most philosophy textbooks, states that inductive reasoning “is the kind of logic normally used in the sciences.’ So the type of reasoning we use when we come to the conclusion of design in life is our normal scientific, empirical reasoning.

There have been many other criticisms of the design argument over the years. I have responded to what I consider to be the more important criticisms in a couple of book chapters, in articles in the Philosophy of Science and other journals, and, most accessibly, on the web at www.crsc.org. If anyone wants to read my responses, this is the place to find them. If you want to read the original criticisms themselves, they are easy to find too, using Google.