The following was posted by jcribb16 in the thread:
I've split it off in sections, to make it easier for people to respond to in detail.
Irreducible complexity is defined as “...a single system which is composed of several well-matched interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.” Simply put, life is comprised of intertwined parts that rely on each other in order to be useful. Random mutation may account for the development of a new part, but it cannot account for the concurrent development of multiple parts necessary for a functioning system. For example, the human eye is obviously a very useful system. Without the eyeball, the optic nerve, and the visual cortex, a randomly mutated incomplete eye would actually be counterproductive to the survival of a species and would therefore be eliminated through the process of natural selection. An eye is not a useful system unless all its parts are present and functioning properly at the same time.