Literature

Behe cuts through the arguments to discover the fine tapestry of life

Review of:
The Edge of Evolution: The Search for the Limits of Darwinism
By Michael J. Behe
Free Press, 2007

Michael Behe's new book has been disowned as a work of science by numerous reviewers in Science, Nature and a host of other publications. Only after reading the book could I understand why the reaction has been so intense! It is not because Behe is betraying science (indeed, he is pre-eminently an empiricist) but because the implications of the data he discusses completely undermine the evolutionary consensus that has long been nurtured by opinion-formers within the scientific community. Furthermore, Behe takes all their best arguments and shows that the evidence actually supports the case for non-random, purposeful explanations of the natural world.

Richard Dawkins' carefully crafted arguments are faced head-on by Behe, with devastating effect. For example, Behe considers several evidences of Darwinism in action (notably sickle cell anaemia providing resistance to malaria, antibiotic resistance in bacteria, antifreeze proteins in Antarctic fish) and completely confounds those who say that ID scientists do not accept the Darwinian mechanisms of mutations and natural selection. Not only does Behe endorse the view that these data are good examples of Darwinism in action, but he goes on to show (using the research of the past decade or so) that these mechanisms are utterly incapable of building the complexity that we observe permeating living things. The phenomenon of mutation and natural selection is uncontroversial. The case presented by Behe using the empirical evidence is that the central Darwinian mechanisms cannot deliver the outcomes required by evolutionary theory.

Another example Dawkins favours is the "arms race" metaphor to describe the struggle for survival in the living world. Behe looks at what is actually happening from his own perspective as a biochemist and shows that a better metaphor is "trench warfare". This is because there is no development of more sophisticated arms but only the exploitation of short-term advantages that fortuitously arise. In most cases, these are examples of malfunctions and genetic loss (more like blowing up a bridge than developing a new weapon).

Dawkins (deducing from theory, p.41): "The arms-race idea remains by far the most satisfactory explanation for the existence of the advanced and complex machinery that animals and plants possess."
Behe (induction from data, p.42): "Far and away the most extensive relevant data we have on the subject of evolution's effects on competing organisms is that accumulated on interactions between humans and our parasites. As with the example of malaria, the data show trench warfare, with acts of desperate destruction, not arms races, with mutual improvements."

Thirdly, Behe concludes that the Blind Watchmaker is a figment of Dawkins vivid imagination. The argument is drawn from the best databases we have of Darwinian processes in action. These are malaria (P. falciparum), the HIV virus and an important intestinal bacterium (Escherichia coli). Both Dawkins and Behe describe the need, within Darwinism, for climbing a mountain step by step up a continuous path. The both recognise the same problems but come to totally different conclusions.

"P. falciparum, HIV and E.coli are all very, very different from each other. They range from the simple to the complex, have very different life cycles, and represent three different fundamental domains of life: eukaryote, virus, and prokaryote. Yet they all tell the same tale of Darwinian evolution. Single simple changes to old cellular machinery that can help in dire circumstances are easy to come by. This is where Darwin rules, in the land of antibiotic resistance and single tiny steps. Burning a bridge that can stop an invading army or breaking a lock that can slow a burglar are easy and effective. But if just one or a few steps have to be jumped to gain a beneficial effect, as with chloroquine resistance, random mutation starts breathing hard. Skipping a few more steps appears to be beyond the edge of evolution." (p.162)
"Why no trace of the fabled blind watchmaker? The simplest explanation is that [. . .] the blind watchmaker does not exist." (p.164)

It is customary to portray Darwinian evolution using the term "tinkering". There is some merit in this, as the mechanisms of Darwinism are both stochastic and opportunistic. Behe recognises tinkering in the way the human body fights malaria.

"The defense of vertebrates from invasion by microscopic predators is the job of the immune system, yet hemoglobin is not part of the immune system. Hemoglobin's main job is as part of the respiratory system, to carry oxygen to tissues. Using hemoglobin to fight off malaria is an act of utter desperation, like using a TV set to plug a hole in the Hoover Dam. Even leaving aside the question of where the dam and TV set came from - which is no small question - it must be conceded that this Darwinian process is a tradeoff of least-bad alternatives. The army in its trenches is suffering loss upon loss. No matter which way it turns, in this war fought by random mutation and natural selection, it is losing function, not gaining." (p.29-30)

Although "tinkering" is a widely used term in evolutionary biology, it is not a term that fits well into biology in general. However, a Gordian Knot tethers most biological thinking to a neodarwinian anchor, because biologists have been taught from infancy that nothing in biology makes sense except in the light of evolution. Behe has cut this Gordian Knot and the effect of this is liberating. Now, we can recognise the pervasiveness of coherent complex systems and exquisitely fabricated structures and we do not need to force-fit these into being the products of "tinkering". (For a recent example, go here). There are various avenues to explore to explain all this, but Behe is quite clear where his thinking is going:

"I conclude that another possibility is more likely: The elegant, coherent, functional systems upon which life depends are the result of deliberate intelligent design". (p.166)