Michael Behe is an Associate Professor of Biochemistry at Lehigh University in the USA who believes that biological diversity derives from common descent but who is sceptical that the Darwinian processes of natural selection are sufficient to generate such complexity. Behe, a Catholic, does not hold to young earth creationism, but instead believes that there are 'irreducibly complex systems' in cellular biochemistry which can only be explained by invoking a God of design. These systems, such as the clotting of the blood and the molecular mechanisms involved in the immune system, only function correctly as complete systems, and so Behe thinks they could not have evolved gradually.

Curiously this position leads Behe to suggest that 'Some features of the cell appear to be the result of simple natural processes, others probably so. Still other features were almost certainly designed' (p208). 'Design' is therefore presented as one of a range of options for explaining biological phenomena. 'The fact that some biochemical systems may have been designed by an intelligent agent does not mean that any of the other factors are not operative, common, or important' (p230).

There are, I think, at least three fundamental flaws with the position that Behe adopts. First, the phrase 'irreducibly complex' simply describes our current ignorance of how a particular biochemical sequence of events evolved. A century ago biologists were convinced that many systems, such as the molecular basis for inheritance, would never receive adequate scientific explanations, but today the complexities of DNA have been largely uncovered. To describe a system as 'irreducibly complex' is to be held a hostage to fortune.

Second, Behe's position is the classic 'god of the gaps' argument of pointing to natural phenomena which science is currently unable to explain and then presenting these phenomena as evidence for god's existence. The problem is that as scientific explanations become adequate for the task, so the postulated 'god' shrinks in stature.

Third, design as a mode of explanation operates on a different level from biochemical explanations. It is perfectly possible to understand all the components of a molecular system in great detail and yet still believe that the system as a whole has been designed. These are complementary not rival understandings of the same entity.

Biblically minded Christians will not see the created order as divided into some portions which have been 'designed' and some which 'occur by natural processes', because they believe that its every aspect has been created by God and is continually sustained by him (Psalm 104). The created world is a seamless cloth of God's activity. There are no 'gaps'. Scientific descriptions represent our limited human attempts to describe God's activities as truthfully as we can. Whether science can currently explain a particular biochemical phenomenon is irrelevant to our faith in God as creator.

Reviewed by
Denis Alexander
(Head of the T Cell Laboratory at The Babraham Institute, Cambridge, and Editor of the journal Science and Christian Belief)