Part I, Part II, Part III, Part IV
In Chapter five, titled "God the Mechanic," Miller takes on Michael Behe, a proponent of intelligent design. Behe is a biochemist, and the first of Miller's interlocutors that can claim to be an expert in a relevant scientific discipline. Behe is known for his term "irreducible complexity." By this term, Behe means that there are certain aspects of biological life that are "irreducibly complex," such that evolution and natural selection are not sufficient as to account for their existence. Specifically, as a cell biologist, Behe claims that the complex structure and machinery of the cell are irreducibly complex, such that if you take away one part the complex, multi-part machine, the entire cell does not work. Evolution and natural selection, according to Behe, cannot account for the simultaneous coming together of all of the separate yet needed parts of the irreducibly complex machine. Now it should be said, that, as a biochemist, Behe subscribes to most of the processes of evolution and long history of the universe and the earth. It is only at the point of the irreducibly complex biochemical systems that Behe sees the need for a designer.
Therefore, Behe argues, one must posit a designer for these irreducibly complex biological machines. Miller seems a little underwhelmed by Behe's argument and calls it merely the same old argument from design, dusted off and repackaged with the language of cellular biology. It is the same argument made by William Paley, the eighteenth century clergyman, who came up with the analogy of the watchmaker. Paley argued a watch demonstrates design, so there must be a designer. In the same way, biological life demonstrates design, therefore there must be an intelligent designer.
Miller attempts to deconstruct Behe's arguments for irreducibly complex machines by demonstrating that each example given by Behe has been definitively shown to be evolved through natural selection from less complex machines. For example, Miller points out that scientists have been able to demonstrate more simple versions of the cellular cilium and the process of coagulation of blood. Basically, scientists have shown that supposedly irreducibly complex biological machines can be formed by borrowing parts from other working machines. The machines become more and more complex over time, but each small change that creates an advantage are selected for by natural selection.
In the end, Miller labels Behe's God the mechanic, who at one point in the distant past created all of the irreducibly complex cellular machines. Miller quotes the following from Behe:
Suppose that nearly four billion years ago the designer made the first cell, already containing all of the irreducibly complex biochemical systems discussed here and many others. (One can postulate that the designs for systems that were to be used later, such as blood clotting, were present but not "turned on." In present-day organisms plenty of genes are turned off for a while, sometimes for generations, to be turned on at a later time.) (p. 162).This argument, of God the mechanic of complex machines billions of years ago, is, according to Miller, the final blow to Behe's hypothesis. Miller states the problem with this hypothesis as follows:
If we choose to give Behe's theory serious consideration, if we treat it as a scientific hypothesis, then we are obliged to ask what would happen to those preformed genes during the billions of years that follow? As any student of biology will tell you, because those genes are not expressed, natural selection would not be able to weed out genetic mistakes. Mutations would accumulate in these genes at breathtaking rates, rendering them hopelessly changed and inoperative hundreds of millions of years before Behe says that thy will be needed (p. 162).