When I come across a new idea, I like to see if there are any relatively simple and obvious arguments that can be levied for or against it. When I first came across ID, this is the simple argument I used that validated it – IMO – as a real phenomenon and a valid scientific concept.
Simply put, I know intelligent design exists – humans (at least, if not other animals) employ it. I use it directly. I know that intelligent design as humans employ it can (but not always) generate phenomena that are easily discernible as products of intelligent design. Anyone who argues that a battleship’s combination of directed specificity and/or complexity is not discernible from the complexity found in the materials after an avalanche is either committing intellectual dishonesty or willful self-delusion – even if the avalanche was deliberately caused, and even if the rocks were afterward deliberately rearranged to maintain their haphazard distribution.
Some have argued that we only “recognize” human design, and that such recognition may not translate to the intelligent design of non-human intelligence. The easy answer to that is that first, we do not always recognize the product of human design. In fact, we often design things to have a natural appearance. That we may not recognize all intelligent design is a given and simply skirts the issue of that which we can recognize.
Second, it is again either delusion or dishonesty to ignore a simple hypothetical exercise: in some cases, were we to find certain kinds of objects/phenomena [edited for clarity] on distant, uninhabited and otherwise desolate planets, would we be able to infer that such were most likely specifically designed by intelligent creatures of some sort for some purpose?
Again, the obvious answer to this except in cases of delusion or or dishonesty is “yes”. Then the question becomes: without a scientifically valid means of making such a determination, how would one be made? Intuition? Common sense? Is the recognizable difference between such artifacts and those that appear to be natural not a quantifiable commodity? If not, how do we go about making the case that something we find on such a planet is not a naturally-occurring phenomena, especially in cases that are not so obvious? There must be some scientifically-acceptable means of making such a determination – after all, resources committed to research depend upon a proper categorical determination; it would quite wasteful attempting to explain a derelict alien spacecraft in terms of natural processes – time and money better spent trying to reverse engineer the design for practical use and attempting to discern the purpose of its features.
Thus, after we make the determination that said object/phenomenon is the product of intelligent design, our investigatory heuristic is different from what it would be were we to assume the artifact is not intelligently designed. A scientific, categorical distinction is obviously important in future research.
The idea that there is no discernible or quantifiable difference between some products of ID and what nature produces without it, or that such a determination is irrelevant, is absurd. One might argue that the method by which ID proponents make the differential evaluation between natural and product of ID (FSCI, dFSCI, Irreducible Complexity, Semiotic System) is incorrect or insufficient, but one can hardly argue such a difference doesn’t exist or is not quantifiable in some way, nor can they argue that it makes no difference to the investigation. One can hardly argue, IMO, that those attempts to scientifically describe that difference are unreasonable, because they obviously point at least in spirit to that which obviously marks the difference. IMO, the argument cannot be against ID in spirit, but rather only about the best way to scientifically account for the obvious difference between some cases of ID and otherwise naturally-occurring phenomena, whether or not that “best accounting” indicts some phenomena as “product of design” that many would prefer not to be the case.
The only intellectually honest position is to admit ID exists; that there is some way to describe the differential in a scientific sense to make useful categorical distinctions (as “best explanation”), and then to accept without ideological preference when that differential is used to make such a determination. If the best explanation for biological life is that it was intelligently designed, then so be it; this should be of no more concern to any true scientist than if a determination is made that some object found on a distant planet was intelligently designed, or if a feature on Mars is best explained as the product of water erosion. To categorically deny ID as a valid, scientific explanatory category (arrowheads? geometric patterns found via Google Earth? battleships? crop circles? space shuttle? potential alien artifacts?) is ideological absurdity.