 Now turn to the world of biology, and in particular turn to the micro-world of the cell and of mechanisms that we find at that level. Take bacteria which use a flagellum, driven by a kind of rotary motor, to move around. Every part is incredibly complex, and so are the various parts, combined. The external filament of the flagellum (called ‘flagellin’), for instance, is a single protein that makes a kind of paddle surface contacting the liquid during swimming. Near the surface of the cell, just as needed is a thickening, so that the filament can be connected to the rotor drive. This naturally requires a connector, known as a ‘hook protein.’ There is no motor in the filament, so that has to be somewhere else. ‘Experiments have demonstrated that it is located at the base of the flagellum, where electron microscopy shows several ring structures occur’ (p. 70). All, way too complex to have come into being in a gradual fashion. Only a one-step process will do, and this one-step process must involve some sort of designing cause. Behe is careful not to identify this designer with the Christian God, but the implication is that it is a force from without the normal course of nature. Irreducible complexity spells design.