An irreducibly complex system cannot be produced directly (that is, by continuous improvements being made by slight, successive modifications of the original "simple" system, as suggested by Darwin), because any missing part would by definition make it nonfunctional and unable to reproduce itself.
In "Darwin’s Black Box: The Biochemical Challenge to Evolution," Michael J. Behe said "An irreducible complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. Since natural selection can only choose systems that are already working, then if a biological system cannot be produced gradually it would have to arise as an integrated unit, in one fell swoop, for natural selection to have anything to act on."
Think of the first horseless carriage as an irreducibly complex system. All of the components of that car are necessary to make it function. Can't take away the wheels, the motor, the chassis, etc. or it wouldn't function as a car. So how did "natural selection" get from the previous, non-functioning version of the car to the complete version?
That, of course, is one of the most profound questions human beings have about our world. How did life begin? If intelligent design were being put forward as an answer to that question, I might embrace it much more easily. However, ID is not being put forward to answer that question, but rather as an alternative theory to evolution.
Because I'm not a member of a Protestant demonination, I don't take every word in the Bible literally, but figuratively. Evolution is not incompatible with my religious beliefs.
Putting religion aside and looking solely at the scientific point of view, even in historical times over the last 5000-6000 years, humanity has evolved from primitive to modern civilization. Now a relatively new theory called intelligent design has been developed to challenge evolution. I would like to understand it. Only then could I determine whether or not I agree with the ID theory.