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 PrintableVersion Darwin's Black BoxThe biochemical challenge to evolutionDARWIN'S BLACK BOX In the last few years, there have been several significant books on the subject of Darwin's evolutionary theory of the origin and development of life, including Michael Denton's Evolution: a theory in crisis, Phillip E. Johnson's Darwin on Trial and now Michael Behe's work. The effect of these has been increasingly disconcerting to the Darwinists. This volume faces the challenge set by Darwin himself: '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'. Often scientists use complex instrumentation to take measurements, but the contents and workings of the 'black box' is a mystery to them. As Behe says, biochemistry was Darwin's black box, as it is to many evolutionary biologists. This book has had a tremendous impact in the USA, its many reviewers admitting that it is factually reliable. One reviewer, James Shreeve, summed up Behe's thesis: 'When examined with the powerful tools of modern biology, but not with its modern prejudices, life on a biochemical level can be a product ... only of intelligent design'. Shreeve adds: 'Coming from a practising scientist ... this proposition is close to heretical'. But it is being taken seriously by the establishment. However, they take refuge in the time factor: Perhaps in 50 years' time we will have an explanation. That sounds like Darwin's same hope concerning the fossil record a century ago. He expected the fossil evidence to become clearer; it has not. Behe takes a chapter to review the biochemical textbooks and research literature and finds a virtual silence on the evolutionary issues he covers: 'None of the papers published in [The Journal of Molecular Evolution] ... has ever proposed a detailed model by which a complex biochemical system might have been produced in a gradual, step-by-step Darwinian fashion' (p.176). Irreducible complexityInevitably, the science covered is difficult, but the author handles it in a less than threatening manner. He uses familiar objects, cartoons or experiences to help the reader picture the argument. The technical sections are kept brief and stripped of the more complicated chemical names. There is an appendix on the biochemistry of life for the general reader. The examples described by Behe are a small selection of a wide range of possibilities. They demonstrate what he describes as 'irreducible complexity' (p.39). These fall into two kinds: highly integrated systems in which every part had to be present from the start for the system to function and cascade systems which comprise many components which depend on each other and which, alone, would have no biochemical advantage. As an illustration of the former, Behe uses the mousetrap as an illustration. All five parts must be in place for it to function. The wood base would not catch a mouse or offer any improvement. The hammer has no conceivable function until the whole trap is present and set. The biological systems described by Behe include the eye (chapter 1), bombardier beetle (chapter 2), bacterial movement (chapter 3), blood-clotting cascade (chapter 4), protein transport (chapter 5), the immune system (chapter 6) and ATP synthesis (chapter 7). Each is worth a review in its own right, but we will limit ourselves to a few examples. The eye was a problem to Darwin, but he and others over the years (down to Dawkins today) have tried to show that stepwise changes to its morphology can be explained and serve as an adequate interpretation of its evolution. Recently, much has been made of a computer simulation (note, not biological experiments) which transform a three-layered flat photosensitive system into a shape similar to the modern human eye. It requires a couple of thousand 'beneficial' computerised mutations which have no genetic parallel. It fails to explain the origin of the photosensitive layer or the brain's role in sight. Behe takes the problem a stage further by examining the biochemical processes that are 'staggeringly complicated' (p.22). Bacteria and bloodAs an example of bacterial movement, the author describes the rotating arm, the flagellum. The diagram of the bacterial motor that powers this motion (p.71) leaves one gasping at the amazing miniaturisation of a complex machine. As he shows (p.192), the genetic blueprint of this structure had to be in place from the beginning of the bacterium's existence. The process of blood-clotting is an example of a cascade system and one that is critical to life. When the skin is damaged, we bleed. If this is uncontrolled, we will bleed to death. An enzyme, thrombin, is needed to enable fibrinogen to form the clot that seals the wound. Of course, if thrombin had free reign, it would lead to extensive coagulation and thickening of the blood. It is, therefore, held in an inactive form, prothrombin, until required. Another enzyme triggers the conversion of prothrombin to thrombin at the right moment. But this too is held in an inactive state until required. There is a series of similar inactive/active materials, the first being triggered by the wound itself. Then, of course, we need a 'switch' to terminate the process! The complexity of the system is mind-boggling. Warfarin is used to kill rats. It does this by displacing vitamin K in the blood-clotting system and so upsets the cascade and causes the animal to bleed to death. Some rats are immune to Warfarin, but they are not advantaged by this. They have a deficient enzyme. This mutant enzyme is unable to react with the vitamin. Of course, this mutant enzyme also upsets the cascade and prevents clotting and so the rat dies of internal bleeding anyway! Origins of lifeBehe looks at a number of 'origin of life' experiments and shows their irrelevance (p.149-150). In recent years, much publicity has been given to an 'RNA world' which postulates how living organisms could have developed from a primitive RNA system. As Behe says, this theory 'ignores known chemistry' (p.171). Michael Behe believes in a common descent (p.176) of the living world and is not a creationist. Yet his conclusion is that 'the complex systems were designed - purposely arranged by an intelligent agent' (New York Times, October 29 1996; see also p.192ff). He says: 'We can be as confident of our conclusion for these cases as we are of the conclusion that a mousetrap was designed' (p.204). To Behe, intelligent design does not exclude microevolutionary processes (p.229), but evolutionary theory is, of itself, an inadequate explanation of living things. 'A rigorous theory of intelligent design will be a useful tool for the advancement of science in an area that has been moribund for decades' (p.231). Dr. Behe says that the purpose of his book is to show that the Darwinian theory of molecular evolution does not work. This he succeeds in doing. In a conference on design in nature last year, theistic evolutionists derided creationist attempts to put intelligent design back on the agenda. Behe shows that it is an inescapable conclusion. It is not light reading, but it is stimulating. This book is essential reading for any who want an honest, authoritative and accurate assessment of the subject. Dr. John Peet© Evangelicals Now - October 1997 |
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