The following is my term paper, graded an "A," from my Philosophy of Evolution college class; it was written in May 2004. I have made some relatively slight modifications to the original draft.
Michael Behe is an "Intelligent Design" theorist. In a paper he wrote, titled Molecular Machines: Experimental Support for the Design Inference and available for review at http://www.arn.org/docs/behe/mb_mm92496.htm, he presents a condensed version of his case for Intelligent Design and against the theory of evolution by natural selection. The key tenet of his argument for design is "irreducible complexity," which he alleges is present throughout the biological world and impossible to achieve through evolution by natural selection. To define this phenomenon, he writes:
By irreducible complexity I mean a single system which is composed of several interacting parts that contribute to the basic function, and where the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced gradually by slight, successive modifications of a precursor system, since any precursor to an irreducibly complex system is by definition nonfunctional.
Behe uses his famous mousetrap argument to explain his point, turning it into an argument by analogy, citing both human and nonhuman natural structures as analogous to a mousetrap in the impossibility of their formation by successive modification.
Behe begins by explicating the mousetrap. A mousetrap has 1. A platform to serve as the base; 2. A hammer to trap the mouse; 3. A spring that is connected to the base that will hold the hammer in place, 4. A catch to release the hammer when set; 5. A bar, connected to the catch, to hold back the hammer when the trap is set. Behe argues that each part of the mousetrap works with all the other parts and that each part is absolutely necessary for the trap to function. He correctly states that if, for example, the hammer was taken out, the mousetrap would effectively cease working. So, he argues, a mousetrap is an irreducibly complex system that must have been designed, since it could not have been created through succession with modification—any precursors, he says, would be worthless.
Behe uses an argument by analogy to connect the mousetrap to biological systems, saying that the design inference he uses with mousetraps must also apply to things like cilia. He goes into detail explaining the complexity of cilia, writing:
Cilia are composed of at least a half dozen proteins: alpha-tubulin, beta-tubulin, dynein, nexin, spoke protein, and a central bridge protein. These combine to perform one task, ciliary motion, and all of these proteins must be present for the cilium to function. If the tubulins are absent, then there are no filaments to slide; if the dynein is missing, then the cilium remains rigid and motionless; if nexin or the other connecting proteins are missing, then the axoneme falls apart when the filaments slide.
So, he argues, missing any part of the modern cilium, function would be impossible and, therefore, the remains would be useless. Half a cilium would be nonfunctional and not favored by natural selection, and, therefore, the modern cilia would never come to be. After all, natural selection cannot anticipate future gain, and so immediate gain must exist for it to select for something. Behe uses the identical argument for complex structures like the human eye and bacterial flagellum, as well as functions like blood clotting and photosynthesis.
Even before moving to objections scientists have raised to Behe’s argument, I wish to name a few of my own. First, Behe talks in the paper of “black boxes.” Saying that sometimes “a key piece of a particular scientific puzzle [is] beyond the understanding of the age,” Behe defines the term as “a machine or structure or process that does something, but the actual mechanism by which it accomplishes its task is unknown.” While arguing for a precise scientific explanation of how structures he calls irreducibly complex could have come to be, he writes, “This is the level of explanation that Biological science eventually must aim for. In order to say that some function is understood, every relevant step in the process must be elucidated.” Unfortunately, Behe is now just setting himself up for trouble.
Here, Behe is clearly guilty of the same offense of which he accuses Darwinians. He is assuming design without being able to explain a bit about how it happened—not a single step in the process. He is looking at the structure of the human eye, assuming design, and leaving that black box shut, not peering into the details of how such design could actually occur. God is not an explanation because God is a way of stopping the cycle of questions. By citing God, research into a particular phenomenon ends—no more knowledge can be gained. For example, think about earthquakes. Suppose, 600 years ago, it was decided that God produced earthquakes. That would have prevented discovery of the truths we know now. In this way, God is a cop-out for what we have yet to understand fully; worse yet, God is an outright impediment to such discovery.
Moving on to a formal retort to Behe’s argument, I visited the website http://www.world-of-dawkins.com/Catalano/box/behe.shtml. Immediately, the writer points out what I just explained: Behe offers no explanation of how Intelligent Design works in terms of steps, laws or explanatory models. He infers design in exactly the same way he accuses evolutionists of inferring selection. Immediately, the site dismantles the key tenet of Behe’s argument: that irreducibly complex systems cannot have been created through succession with modification. First, the site reminds us that biochemical structures “evolve layer upon layer, contingency upon contingency, always in flux, and retooling to serve current functions.” That means, if we use the mousetrap example momentarily, the function could have changed over the course of time. Say the base came into existence first. It could have been selected for as an effective paperweight. Then say the hammer and spring mutated into existence. Combining all three now, we find ourselves with something that can clip several pieces of paper together. And so it continues until the function of mouse catching comes to be.
Another Behe falsifier is called “improvements become necessities.” Dr. H. Allen Orr writes:
An irreducibly complex system can be built gradually by adding parts that, while initially just advantageous, become—because of later changes—essential. The logic is very simple. Some part (A) initially does some job (and not very well, perhaps). Another part (B) later gets added because it helps A. This new part isn’t essential, it merely improves things. But later on, A (or something else) may change in such a way that B now becomes indispensable. This process continues as further parts get folded into the system.
Dr. Orr helpfully uses this theoretical objection to Behe’s argument for more concrete purposes when commenting that the creation of lungs from air bladders used to be simply a non-essential improvement for terrestrial exploration. When organisms grew to be terrestrially bound, however, that improvement became crucial to survival. This shows how as mutations led away from aquatic life and toward terrestrial existence, what was once an improvement transformed itself into an essentiality, all without design.
Another anti-Behe attack utilized criticizes his argument by analogy as adequate proof for his irreducible complexity theory. The writers of this site say that Behe essentially argues:
A mousetrap is “irreducibly complex”—it requires all of its parts to work properly
A mousetrap is a product of design.
The bacterial flagellum is “irreducibly complex”—it requires all of its parts to work properly.
Therefore the flagellum is like a mousetrap.
Therefore the flagellum is a product of design.
This is an example of an inductive argument, and so the conclusion presented is not a certainty; it is merely very likely if the premises are valid. But, the comparison is not a strong one because while we know the process by which a mousetrap is designed, as previously stated, we have no such process for how biological things could have been intelligently designed (again, God is just a means of halting investigation). Besides that possibly fatal flaw, the argument also has a couple of other holes.
For example, Behe does not even attempt to resolve the issue of how the designer was designed. A designer who created such a wondrous thing as the human eye must be equally or more wondrous himself—and so equally needy of being designed. In addition, the website explains, "To Behe, a system has evolved when he, or others, can imagine how it has evolved, otherwise it was a product of intelligent design." This is clearly insufficient evidence to disprove the theory of evolution, and a rationale that Dr. Richard Dawkins would likely term "the Argument from Personal Incredulity." Quite simply, evolution is a slow process of tiny modifications. Things only become clear in retrospect, so it's hardly surprising that some products of evolution cannot be picked apart right now. After all, evolution has occurred for billions of years, but we discovered the phenomenon less than 200 years ago. Behe wishing for a complete explanation of every evolved structure, even those perhaps still evolving, is blatantly setting evolution up to fail.
The other argument from design I'll cover in this examination appears at http://www.infidels.org/library/modern/theodore_drange/tuning-revisited.html and is titled "The Fine-Tuning Argument Revisited (2000)." Rather than questioning evolution as a good explanation for how different species developed on Earth, this argument aims to give God a role as the planner of our physical constants. On this website, Theodore M. Drange writes both the argument and the refutation. First, he presents the argument from design, quoted here:
(P1) The particular group of values that exists for the fundamental physical constants of our universe (call it "GPC") is just one of a huge number of different groups of values, all of which are physically possible (i.e., not ruled out by more basic laws).
(P2) For all, or at least a large number, of the various groups of values mentioned above, the probability of the existence of any particular group is not considerably less than the probability of the existence of GPC itself.
(P3) It is not the case that there exist a great many worlds (or regions of spacetime), separated from our observable universe, each with its own group of values for fundamental physical constants.
(C4) Therefore [from P1, P2, & P3], the existence of GPC is exceedingly improbable.
(P5) GPC is the only group of values for the fundamental physical constants of a world (or region of spacetime) that would permit the origin, development, and continuation of life as we know it within that world.
(P6) The capability of permitting life as we know it is a very special feature within the set of hypothetical physically possible worlds.
(C7) Hence [from C4, P5, & P6], the existence of GPC is remarkable, surprising, and in need of explanation.
(P8) Given the truth of (C7), the hypothesis that GPC was a product of intelligent design (call it "IDH") is the very best explanation there is for the existence of GPC.
(C9) It follows that there is good evidence that IDH is true.
On its face, this argument for the truthfulness of Intelligent Design seems valid, in that the premises and earlier conclusions do logically seem to lead to the final conclusion. That said, it is also an inductive argument (the inference to the best explanation) and therefore cannot be sound because it cannot be certainly known. That, however, is a moot point because Drange skillfully shows how woefully weak this argument is by picking apart several of its premises and therefore nullifying the conclusion.
Drange's first objection calls P1 into question. Drange correctly points out that people advocating what he terms "The Fine-Tuning Argument" have yet to prove that physical constants different than what currently exist could ever be. Drange writes, "It may be that scientists of the future will come up with a [theory] that will show why values for physical constants other than [those currently existing] are not physically possible." Drange does not provide positive evidence for the counterclaim, but simply shows that the premise given has not been proven. The one proposing the argument bears the burden of proving the premises, not the person raising a doubt.
Next, Drange attacks P2 by saying an Intelligent Design theorist proposing the Fine-Tuning Argument must provide evidence that most of the various possible worlds (each with differing constants) have about as much of a chance of existing as our current universe. If that isn't the case, our current constants are not all that surprising, because the "competition" is improbable. However, again, this is a moot point because, "Physicists do not have any data on the basis of which such probability computations could be made." Therefore, we have no idea whether our constants are less probable, more probable or equally probable as compared to other constants (themselves questionable in the absence of evidence they are physically possible).
The next objection raised skewers P3 by suggesting that many different universes may exist, and so the existence of one with our constants is hardly surprising when taken in that context. He then extends the criticism, applying it to the claim that life's presence in this universe is remarkable. If there are multiple universes "then the fact that we happen to exist in one of the very few worlds capable of sustaining life as we know it would not be...incapable of being reasonably explained simply by...chance." Again, though there is not solid evidence for the existence of multiple worlds, neither can it be conclusively and self-evidently said that multiple ones don't exist.
Another fundamental problem with people making this kind of design argument is that they seem to think that since life as we know it could not come to be without specific constants, that those constants necessarily had to be. This is an unreasonable interpretation of the Anthropic Principle. Dr. Daniel Dennett explains the reasonable version of that principle as essentially: It must be the case that if life as we know it depends on specific physical constants, then, since such life exists, the world contains those constants. This has nothing to do with the necessity of the constants, per se. Rather, it is simply explaining that, if something is necessary for something else to exist, and that second something does exist, the first something by necessity must. The unreasonable Anthropic Principle interpretation is fallacious in assuming that life as we know it had to evolve (thereby making the constants compulsory), which is a baseless assumption.
The next stated objection questions whether our universe and its characteristics are special at all (chipping away at P6 of the argument). If there are other universes with differing physical constants (a possibility that cannot be ruled out without evidence), each one might have fascinating things occurring inside it totally unrelated to life. Basically, Drange is saying that we are putting too high a value on life by seeming to think nothing else could be more interesting. Intelligent Design theorists are also falsely leaping to the conclusion that we can even comprehend what might develop in other universes, while Drange argues we can't really know how things would progress. Drange writes:
And even if it were true that no other possible world, with different values, would have permitted life as we know it, nevertheless, whatever world had come about, it would probably have had some other unique feature(s) at least as interesting as the property of permitting life as we know it. From this perspective, there would be nothing special about our universe, and that makes [the premise] totally unsupported and thus doubtful.
The final objection relates to the premise that design is the best explanation for our universe‘s constants. Though Drange goes on about this for quite a while, I'll focus on just a few objections here. First, Drange argues that Intelligent Design is flawed because there is no information about either the designer(s) or the designing process. It is essentially a theory comprised of an effect without the benefit of a cause. He also raises an interesting point in wondering why, if the designer(s) wished to create an intelligent life form, they created a universe so sparsely populated with life (which itself took billions of years to evolve and billions more to gain intelligence). And, going back to a Behe problem, Drange wonders where those who designed the universe came from. Drange considers this "at best, simply replacing one mystery by an even greater mystery."