The Edge of Evolution: The Search for the Limits of Darwinism [Paperback]

Behe's first book, "Darwin's Black Box", was one of the books that made the Intelligent Design debate more visible. Proponents of ID argue that it is possible to argue on the basis of scientific evidence that life (or the universe) requires intelligent input of some sort. This differs from creationism, that argues fundamentally for the presence of God on the basis of the authority of a religious text. However, since like creationism, ID excludes the possibility of a naturalistic explanation of various phenomena, it has aroused the indignation of many of the same opponents, who are keen to characterise ID as being no more than "creationism in a cheap tuxedo".

So it is inevitable that this book will polarise the opinions of readers - or potential readers: enough people who know Behe by reputation may well weigh in on either side of the debate without actually bothering to read "The Edge of Evolution".

However, what is of more importance than the debate between nay-sayers and yay-sayers are the issues that Behe raises. He goes substantially beyond "Darwin's Black Box" here. In his first book, he argues that complex biochemical machinery could not arise by chance. In this book, he suggests that "the edge of evolution" - the most complicated achievement that a purely darwinist process could hope to achieve - is much less complex than (say) a machine like the bacterial flagellum. He makes the case for this in mathematical terms - calculations that are more biologically specific than those presented by Dembski in "The Design Inference" - and backs up his case by looking at two specific biological systems in some detail - the malaria parasite and the AIDS virus.

In effect, he is arguing that whilst darwinism is an adequate means of explaining microevolution (such as antibiotic resistance, the preservation of the sickle-cell mutation, and resistance to antimalarial drugs), it is not powerful enough to produce macroevolution. He is quite careful about his terminology here; he accepts both natural selection and common descent, but argues that random mutation - a required plank of darwinism - is not up to the task required of it.

One of the major charges made against ID is its refusal to identify either a designer or a process. Behe points out again that identification of a designer is not inherent in the identification of design, but does propose a process. He argues that life as we see it has to be a highly non-random outcome of processes - and therefore, the designer might work by manipulating these processes. This might mean engineering mutations throughout the history of life to bring about the desired end. Is this distinguishable from random mutations? He would argue, yes - if an outcome is very low probability, then it is not an adequate or reasonable explanation to suggest that it is random. Even Dawkins - the loudest proponent of darwinism - accepted this in "The Blind Watchmaker", where he suggested that if life could be shown to be unlikely to arise once in the galaxy, then the assertion that life was the product of chance would be unreasonable. Of course, this was written in those innocent, pre-"Rare Earth" days when Carl Sagan was confidently asserting that there were probably thousands of intelligent life forms all around us in the universe.

Behe's book is a serious attempt to move the debate on - and has been accompanied by serious attempts by darwinist heavyweights to get people to ignore him - see Behe's blog on amazon.com for details of his interactions with such. Of course, you need an open mind if you are going to accept that there might be an intelligent designer - whoever or whatever that happened to be. But isn't that what we post-enlightenment thinkers are supposed to have?

Despite the hostility of some reviewers, I found this to be a good book.

Behe examines latests results regarding the powers of random mutation and wants it wanting. In the books' centerpiece examples, he examines how much random mutations can do in malarial parasites and bacteria. These organisms have very small generation times, so scientists have been able to test in the lab what would be worth millions of years of time for us vertebrates. According to Behe's analysis, evolution relying on random mutation has very limited powers.

Some critics here have pointed to dog breeding and bacterial resistance as counterexamples to Behe. In my opinion these critics should at least have mentioned that Behe actually uses both as examples of the powers and limits of random mutation + natural selection in his book. In my opinion, he is correct to point out that one has to analyse what is actually going on in the changes to see whether darwinism is true. In the dog mutations, no new molecular machines, cell types etc. are created. Having different dog breeds don't automatically demonstrate that the same process could have built man gradually from small bacteria.

Indeed, most criticisms are well dealt with by Behe in his book. Others are dealt with at his Amazon blog. In my opinion, his arguments are not easy to dismiss.

In the book, Behe also expands on his influential "irreducible complexity" argument again undirected evolution. Behe's criticism is made unusual by the fact that he accepts common descent, but believes that it was guided by an intelligent designer. Many other scientists have been of the opinion that darwinian processes as traditionally conceived do very little, but a smaller percent believe in the theory of Intelligent design: the idea that life's complex machinery came about through intelligent design, just as human machinery came about through human design.

In this book biochemist Michael Behe, Professor of Biological Science at Lehigh University, essentially blows out of the water any idea that random mutations can provide the neccessary genetic variation needed for biological complexity. With extremely up-to-date research, well described, he shows with authority that the chances of getting the needed amino acid sequences in a protein, through DNA mutation, to achieve any functional benefit - are vanishingly small. His method is to look where we can actually document mutations in organisms which have very large numbers and rapid generation times - in particular malaria, HIV, E.coli. These numbers give us the statistical power needed to assess the probability of random mutations forming new protein binding sites and properties. Novelty just does not happen - and is of course far less likely in small genetic populations of mammals such as us. Darwinists will fume at this - because although Behe accepts both an ancient earth and common descent, he has removed the foundation for purposeless evolution. He rightly acknowledges situations where natural selection can and does work on very minimal variation - but demonstrates an 'edge' beyond which evolution fails to produce the goods. His conclusion that intelligence or mind is behind the complexity of biology, is evidence based and superbly argued.