The Design Criteria

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One prediction of all design-centric venues is that when agencies interact with nature they tend to leave traces of their involvement behind. Most often those traces are in the form of signs of work. IDists have defined what such traces would look like wrt biology:

The criteria for inferring design in biology is, as Michael J. Behe, Professor of Biochemistry at Leheigh University, puts it in his book Darwin ‘ s Black Box: “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: the ordering of separate components to achieve an identifiable function that depends sharply on the components.”

He goes on to say: ” 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.”

Then we have-

Irreducible Complexity:
IC- A system performing a given basic function is irreducibly complex if it includes a set of well-matched, mutually interacting, non-arbitrarily individuated parts such that each part in the set is indispensable to maintaining the system’s basic, and therefore original, function. The set of these indispensable parts is known as the irreducible core of the system. Page 285 NFL

Numerous and Diverse Parts If the irreducible core of an IC system consists of one or only a few parts, there may be no insuperable obstacle to the Darwinian mechanism explaining how that system arose in one fell swoop. But as the number of indispensable well-fitted, mutually interacting,, non-arbitrarily individuated parts increases in number & diversity, there is no possibility of the Darwinian mechanism achieving that system in one fell swoop. Page 287

Minimal Complexity and Function Given an IC system with numerous & diverse parts in its core, the Darwinian mechanism must produce it gradually. But if the system needs to operate at a certain minimal level of function before it can be of any use to the organism & if to achieve that level of function it requires a certain minimal level of complexity already possessed by the irreducible core, the Darwinian mechanism has no functional intermediates to exploit. Page 287

So if what we are investigating fits any of the descriptions above then we have more than enough to check into the possibility that is was designed- meaning we would run it through the explanatory filter. If it gets to the last node and matches any of the above, then we infer it was intentionally designed.

Dr Behe responds to IC criticisms:

One last charge must be met: Orr maintains that the theory of intelligent design is not falsifiable. He’s wrong. To falsify design theory a scientist need only experimentally demonstrate that a bacterial flagellum, or any other comparably complex system, could arise by natural selection. If that happened I would conclude that neither flagella nor any system of similar or lesser complexity had to have been designed. In short, biochemical design would be neatly disproved.- Dr Behe in 1997