In recent years, biologists have discovered an exquisite world of nanotechnology within living cells - complex circuits, sliding clamps, energy-generating turbines and miniature machines. For example, bacterial cells are propelled by rotary engines called flagellar motors that rotate at 100,000rpm. These engines look like they were designed by engineers, with many distinct mechanical parts (made of proteins), including rotors, stators, O-rings, bushings, U-joints and drive shafts.
The biochemist Michael Behe points out that the flagellar motor depends on the co-ordinated function of 30 protein parts. Remove one of these proteins and the rotary motor doesn't work. The motor is, in Behe's words, "irreducibly complex".
This creates a problem for the Darwinian mechanism. Natural selection preserves or "selects" functional advantages as they arise by random mutation. Yet the flagellar motor does not function unless all its 30 parts are present. Thus, natural selection can "select" the motor once it has arisen as a functioning whole, but it cannot produce the motor in a step-by-step Darwinian fashion.
Natural selection purportedly builds complex systems from simpler structures by preserving a series of intermediates, each of which must perform some function. With the flagellar motor, most of the critical intermediate structures perform no function for selection to preserve. This leaves the origin of the flagellar motor unexplained by the mechanism - natural selection - that Darwin specifically proposed to replace the design hypothesis.
Is there a better explanation? Based on our uniform experience, we know of only one type of cause that produces irreducibly complex systems: intelligence. Whenever we encounter complex systems - whether integrated circuits or internal combustion engines - and we know how they arose, invariably a designing intelligence played a role.
For Dal M.
http://www.podomatic.com/people/index/intelligentdesign