For example, a simple mouse trap is made from at least six components: the platform, the spring, the hammer, the catch, the holdback bar, and staples. Without any of the components the machine will not function. Furthermore, each of the components have to be designed to a specific size and placed in a specific place in order for the mouse trap to function.

Thus, a simple mousetrap is irreducibly complex. Nothing can be missing and it could not have arisen one piece at a time. It is not possible that the mousetrap could have “just happened” as components with other previous uses (such as a Popsicletm stick, a paper clip, a piece of wood, and a ball point pen spring) were put into a box and shaken. Because it is a irreducibly complex machine with multiple components designed to perform specific functions, it is also obvious that it was built by an intelligent designer.

Biological features are also made from similar irreducibly complex structures, even at the smallest molecular level.

For instance, there are millions of organisms, including human bodies, which use a structure called a cilium to either swim or move things around within a creature. Cilia in our lungs are hair-like structures attached to cells which beat like a whip in order to move foreign particle out of our lung. Sperm use cilium to swim. Dr. Behe estimates that TEN THOUSAND technical papers have been published concerning cilia.

Like the mouse trap, cilia require several components in order to operate. In the case of a mousetrap, the components are metal and wood, in the case of cilia, they are specifically shaped proteins. The very minimum number of components needed for a cilia to operate are three: proteins forming the hair like fibers (the rotor), linking proteins to keep adjacent fibers from flying apart (links), and proteins to slide the cilia past one another causing its whipping motion (the motor). Without one of these components - the structure would not function. Thus, the cilium is an irreducibly complex machine. In reality, one cilium contains over two hundred different proteins and it is likely that all almost all of these would be required for its operation. However, just the three listed demonstrate the impossibility of this structure coming together by chance.

In Dr. Behe’s words, “The amount of scientific research which has been done...leads many people to assume that even if they don’t know how cilium evolved, somebody must know. But the search of professional literature proves them wrong. Nobody knows.” Could it be that “nobody knows” how cilia could have evolved because irreducible machines, of which biological life is replete with examples, can never be explained without a supernatural designer? By eliminating this possibility, it is no wonder ten thousand papers can be written on the operation of cilia and not even one can explain its origin!