You still have not answered the question. Assuming Chemical X which you believe to be IC, how do we test it? How do we know that it is IC and not merely too complex for us to describe with current knowledge? Until you can answer this, IC is dead in the water.
A better question is "How do we know that it isn't another example of a protein built by scaffolding or change in function?"
Since we know of several processes which automatically result in apparent irreducible complexity that aren't at all irreducibly complex, how do we distinguish between the two? How do we distinguish between extant proteins that just "look" irreducibly complex but are a result of such known and studied processes, and those that really are irreducibly complex?
The claim if irreducible complexity only works if it is 100% certain. If it isn't certain, we have two possible alternatives, and we must then consider the full weight of the rest of the confirming evidence for evolution in determining whether it is more likely that a system is IC, or instead a result of an evolutionary process that results in "apparent" IC like scaffolding or change of function.
The full weight of the evidence for Evolution (geologic, genetic, etc.) is quite convincing. This makes it much more likely that the unknown history of these systems are more likely to be scaffolding or change of function or another IC producing mechanism than miraculous creation by a designer.
™ Version 4.2