Michael Ruse "Darwin's New Critics on Trial" 1999

erhaps encouraged by their self-awarded success, the new Creationists have recently started to break from their strategy of unrelenting attack. Thanks to biochemist Michael J. Behe, author of Darwin’s Black Box: The Biochemical Challenge to Evolution (1996), they have started to lift the veil from their own beliefs about origins qua science. Indeed, one might say they have ripped the veil in twain with trumpets accompanying: ‘The result is so unambiguous and so significant that it must be ranked as one of the greatest achievements in the history of science. The discovery rivals those of Newton and Einstein, Lavoisier and Schrödinger, Pasteur and Darwin’ (pp. 232-3)

Let us not be distracted by such grandiose self promotion. Let us move to the arguments. It is Behe’s claim that there are facts of organic nature whose origin cannot be evolutionary. In fact, they cannot be natural at all, meaning the consequence of regular unguided law. These facts, marked by irreducible complexity, have to be the product of a designer, however construed:

By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. Since naturalselection can only choose systems that are already working, then if a biological system cannot be produced gradually it would have to arise as an integrated unit, in one fell swoop, for natural selection to having anything to act on. (p. 39)

As a matter of fact, Behe does not want to rule out a natural origin for all irreducible complexities, but we learn that as the complexity rises, the likelihood of getting things by any indirect natural route ‘drops precipitously’ (p. 40). As a physical example of an irreducible complex system, Behe instances a mousetrap — something with five parts (base, spring, hammer, and so forth), any one of which is individually necessary for the mousetrap’s functioning. It could not have come into being naturally in one step and it could not have come gradually — any individual piece would not function properly and any part missing would mean failure of the whole. It had to be designed and made by a conscious being: a fact which is true also of organisms. Behe instances the phenomenon of blood clotting as an organic example of such intelligent design. ‘The purposeful arrangement of parts’ (p. 193) is the name of the game.

As it happens, Behe’s choice of a mousetrap as an exemplar of intelligent design has been somewhat unfortunate. All sorts of parts can be eliminated or twisted and adapted to other ends. There is no need to use a base, for example. You can just attach the units directly to the floor: a move which at once reduces the trap’s components from five to four. But even if the mousetrap were a terrific example, it would hardly make Behe’s point. No evolutionist ever claimed that all of the parts of a functioning organic feature had to be in place at once, nor did any evolutionist claim that a part currently used for one end always had to have that function. Ends get changed and something introduced for one purpose might well take on another purpose: only later might it get fixed in as essential. Against the mousetrap, let me take on the example of an arched bridge, with stones meeting in the middle and with no supporting cement. If you tried to build it from scratch, the two sides would keep collapsing as you started to move the higher stones in the middle. What you must do first is build an understructure. It is now no longer needed; although if you were not aware that it had once been there you might think it a miracle that the bridge was ever built. Intermediate positions were impossible. Likewise in evolution: let’s say some pathway exist; a set of parts sits idle on the pathway; then these parts link up; and finally the old pathway is declared redundant and removed by selection. Only the new pathway exists, although without the old one the new one would have been impossible.

Moving from analogies and pretend examples, let me be absolutely fair and say that we are not now dealing with someone whose knowledge of science is restricted to Natural History and the New York Review of Books. Although he has but a crude understanding of evolution through natural selection, Behe is a real scientist. Yet, this perhaps makes things worse rather than better. Naïveté is no excuse. Behe’s case for the impossibility of small-step natural origin of biological complexity has been trampled upon contemptuously by the scientists working in the field. It is not that they just disagree, but that they think his grasp of the pertinent science is weak and his knowledge of the literature curiously (although conveniently) outdated. Particularly censorious are those scientist whose work has been used by Behe, against them, to support his position. Russell Doolittle, the world’s expert on the evolution of blood clotting, is a case in point. In a 1997 lecture discussing the phenomenon of blood clotting, which involves a kind of ‘cascade’ as first one biochemical reaction occurs and then this triggers another and so forth, he uses the notions (drawn from ancient Chinese science) of yin and yang. First one thing (yin) happens, and then another (yang) in reaction, and so on down the line.

About this Behe writes:

Doolittle’s scenario implicitly acknowledges that the clotting cascade is irreducibly complex, but it tries to paper over the dilemma with a hale of metaphorical references to yin and yang. The bottom line is that clusters of proteins have to be inserted all at once into the cascade. This can be done only by postulating a ‘hopeful monster’ who luckily gets all the proteins at once, or by the guidance of an intelligent agent. (1996, p. 96)

Doolittle’s response is that Behe’s science is simply out of date. Far from the evolution of clotting being a mystery, the past three decades of work by Doolittle himself and others have thrown significant light in the ways in which clotting came into being. More than this, it can be shown that the clotting mechanism does not have to be a one-step phenomenon with everything already in place and functioning. One step in the cascade involves fibrinogen, required for clotting, and another, plaminogen, required for clearing clots away. Doolittle writes:

It has become possible during the last decade to ‘knock out’ genes in experimental organisms. ‘Knock out mice’ are now a common (but expensive) tool in the armamentarium of those scientists anxious to cure the world’s ills. Recently the gene for plaminogen was knocked out of mice and, predictably, those mice had thrombotic complications because fibrin clots could not be cleared away. Not long after that, the same workers knocked out the gene for fibrinogen in another line of mice. Again, predictably, those mice were ailing, although in this case 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 of irreducible complexity, the entire ensemble of proteins is not needed. Music and harmony can arise from a smaller orchestra. (1997, [Boston Review 22 (1)] p. 29)

Behe’s knowledge of evolution is suspect. His knowledge of his own area of science is suspect. And the same is true when he moves into philosophy and theology. The common complaint about evolutionary theory is that it cannot be properly checked. The critics claim that it is too flabby to yield testable predictions: it is in some sense unfalsifiable. But whether or not this is true (I do not happen to think it is), such a complaint must certainly be made of Behe’s theory. How can you tell when irreducible complexity can be explained by evolution and when it must be explained by something else (or Something Else)? Behe himself admits there is no sharp line and he gives no real answers to this problem. Newton and Einstein and those other great scientist to whom he likened himself produced work that did lead to quantification and to measurement and prediction. As it stands, Behe’s ideas can simply be protected against any counter evidence. You can explain some phenomenon through evolution? Then, either the phenomenon was not irreducibly complex or it was not complex enough. You cannot explain some phenomenon through evolution? Then either the phenomenon is too complex for an evolutionary explanation or you will later find such an explanation. Once again, heads, I win; tails, you lose.

And in any case — and here I will bring to an end my discussion of Behe — suppose you accept his conclusion about the existence of a Designer. What precisely is the role of this Designer? Qua scientist, Behe is careful not to identify it with the Christian God. But let us suppose such a Designer does exist and is at work producing irreducibly complex organisms. Who then is responsible when things go wrong? What about mal-mutations causing such awful things as Tay-Sachs disease and sickle-cell anemia? Is this just the fault of no one, or do we blame evolution? Why does the Designer not step in here? It (let us not pre-judge its sex) is pretty clever and could surly fix just one bad move — the whole point is that It can produce the irreducibly complex. So why not the not-very-complex-but-absolutely-dreadful? Behe says that raising this problem is raising the problem of evil — How can an all-powerful, all-good God allow pain? which is so. But labeling the problem does not make it go away.

There are some standard arguments against the problem of evil — that it is a function of human free will, for instance — which may or may not work. My point now is simply that Behe himself gives no reason to think that the problem can be solved or will vanish. He is in as much trouble in the realm of philosophical theology as he was in the realm of biological science. He has offered us a freshened-up version of the old ‘God of the gaps’ argument for the deity’s existence: a Supreme Being must be invoked to explain those phenomenon for which I cannot offer a natural explanation. But such an argument proves only one’s own ignorance and inadequacy. It tells us nothing of beings beyond science. In the words of the Christian theologian and martyr Dietrich Bonhoeffer, ‘We are to find God in what we know, not in what we don't know’ (Letters from Prison, 1979, p. 311).

Darwin's New Critics on Trial:

Irreducible Complexity

by Michael Ruse