ID is based on three premises and the inference that follows (DeWolf et al., Darwinism, Design and Public Education, pg. 92):

1) High information content (or specified complexity) and irreducible complexity constitute strong indicators or hallmarks of (past) intelligent design.

2) Biological systems have a high information content (or specified complexity) and utilize subsystems that manifest irreducible complexity.

3) Naturalistic mechanisms or undirected causes do not suffice to explain the origin of information (specified complexity) or irreducible complexity.

4) Therefore, intelligent design constitutes the best explanations for the origin of information and irreducible complexity in biological systems.

So to falsify ID all you have to do is show that undirected causes such as natural selection and drift can produce CSI and/ or IC.

The positive case can be simplified by:

Our ability to be confident of the design of the cilium or intracellular transport rests on the same principles to be confident of the design of anything: theordering of separate components to achieve an identifiable function that depends sharply on the components.- Behe in “Darwin’s Black Box”

 

” Might there be some as-yet-undiscovered natural process that would explain biochemical complexity? No one would be foolish enough to categorically deny the possibility. Nonetheless, we can say that if there is such a process, no one has a clue how it would work. Further, it would go against all human experience, like postulating that a natural process might explain computers.” Ibid

The positive case for ID is very similar to the positive case for archaeology and forensic science- we look for signs of work and/ or counterflow.

Dr Behe responds to some critics:

Now, one can’t have it both ways. One can’t say both that ID is unfalsifiable (or untestable) and that there is evidence against it. Either it is unfalsifiable and floats serenely beyond experimental reproach, or it can be criticized on the basis of our observations and is therefore testable. The fact that critical reviewers advance scientific arguments against ID (whether successfully or not) shows that intelligent design is indeed falsifiable.

In fact, my argument for intelligent design is open to direct experimental rebuttal. Here is a thought experiment that makes the point clear. In Darwin’s Black Box (Behe 1996) I claimed that the bacterial flagellum was irreducibly complex and so required deliberate intelligent design. The flip side of this claim is that the flagellum can’t be produced by natural selection acting on random mutation, or any other unintelligent process. To falsify such a claim, a scientist could go into the laboratory, place a bacterial species lacking a flagellum under some selective pressure (for mobility, say), grow it for ten thousand generations, and see if a flagellum–or any equally complex system–was produced. If that happened, my claims would be neatly disproven.(1)

How about Professor Coyne’s concern that, if one system were shown to be the result of natural selection, proponents of ID could just claim that some other system was designed? I think the objection has little force. If natural selection were shown to be capable of producing a system of a certain degree of complexity, then the assumption would be that it could produce any other system of an equal or lesser degree of complexity. If Coyne demonstrated that the flagellum (which requires approximately forty gene products) could be produced by selection, I would be rather foolish to then assert that the blood clotting system (which consists of about twenty proteins) required intelligent design.

Let’s turn the tables and ask, how could one falsify the claim that, say, the bacterial flagellum was produced by Darwinian processes?

Even the explanatory filter demands a positive case for ID- one of specification on top of the elimination of necessity and chance. And the elimination of necessity and chance before considering a design inference is mandated by science- see Newton’s four rules of scientific reasoning.

“Thus, Behe concludes on the basis of our knowledge of present cause-and-effect relationships (in accord with the standard uniformitarian method employed in the historical sciences) that the molecular machines and complex systems we observe in cells can be best explained as the result of an intelligent cause.

In brief, molecular motors appear designed because they were designed” Pg. 72 of Darwinism, Design and Public Education

Cause and effect relationships-> science 101.