ID Defined | Uncommon Descent
Intelligent design - New World Encyclopedia
The theory of intelligent design (ID) holds that certain features of the universe and of living things are best explained by an intelligent cause rather than an undirected process such as natural selection.
Note that the theory itself doesn't necessarily implicate a god of any sort. ID theory is based on the observable, quantifiable difference between what humans intelligently design, and that which appears to be not guided by intelligence (chance, natural law, etc.)
1. Intelligent design as theorized in its most ubiquitous form (above) is (I contend) as irrefutable a scientific fact as the most ubiquitous theoretical forms of evolution (populations evolve over time) and gravity. Humans utilize intelligent design to intentionally plan and construct things which we don't expect to be generated by chance and necessity, necessity being the predictable behavior of natural laws.
2. Forms of ID are already in use in the scientific community, whether by name or not, whether denied as ID or not; forensics, for example, determines if a murder or a fire was intentionally designed by a deliberate agent, or if it was an accident. SETI, for example, is searching for evidence of extra-terrestrial intelligence (although now they'd like to change their name to "artificiality", which is again simply sidestepping the issue via dishonest semantics).
3. Science itself relies on the intelligent design of theories and experiments to advance. Human intelligent design generates things that are obviously and intuitively different than that which we normally expect chance and natural laws to produce on their own. IOW, if we found something like a very weird-looking spaceship on Mars, that had a power-source and computer-like controls, we wouldn't go around looking for a "natural" explanation to explain it; we would intuitively know it was designed by some form of intelligence.
4. The question isn't really if intelligent design exists, but rather if it exists outside of human beings, and if so, can it offer a more precise and functionally signifcant predictive model that can be used to reliably discern between non-designed phenomena and those produced by I.D.? After all, we might not always be able to intuitively identify artifacts of intelligence.
5. Unless one is going to argue that intelligence is unique to humans, then theorizing that non-humans might also have intelligence is a reasonable scientific theory - much as theories that some animals have various levels of intelligence as displayed by their capacity to innovate tool use and learn and use some rudimentary languages, and plan their actions to various degrees.
Also, we examine what other forces produce on Earth, like vucanism or erosion by air or water, and use those findings to guide our explanations of what we find on other worlds; this is nothing more than extrapolating what known commodities are known to produce into a explanatory framework for finding similar such activity elsewhere.
6. The problem of the definition of "natural". First, in normal usage, "natural" is a juxtaposition of "artificial", which means made by man. However, this dichotomy is false; scientists do not propose that humans, or human intelligence, is unnatural; in fact, according to science, the intelligence and foresighted design capability that humans possess must be generated entirely by natural processes. Humans are part of the natural world, and operate entirely within the natural world, according to science.
Unless one is going to argue that humans are not part of the natural world, then it is obvious that intelligent design is part of the natural world, and does produce phenomena that cannot be readily explained without it. Just as gravity produces phenomena and evolution explain phenomena that cannot be readily (scientifically) explained without appeal to those forces, so too does intelligent design produce phenomena (computers, battleships, space shuttles) that defy description or explanation with it.
7. Unless one wishes to argue that the existence of computers and space shuttles can be best described without appeal to a designing intelligence, then we must agree to the validity of the ubiquitous version of the theory, whether or not any more precise and valid predictive commodities derived from that theory have yet been developed or established.
Intelligent Design, like evolution, is a fact and a scientific theory, whether or not it has yet produced any successful rigorous predictive commodities that can reliably discern ID as the best explanation of a phenomena. Let's not forget that when Darwin first theorized evolution, he had no method for inheritance and no rigorous predictive capacity.
ID theorists are currently attempting to develop a rigorous, predictive model for identifying when a phenomena is best explained as the product of ID; some of those attempts are: irreducible complexity (Behe), the explanatory filter (Dembski), and the FSCI limitation of 500-1000 bits (Meyer).
Contrary to some who believe that such a designation indicates the "end" of scientific research into the phenomena in question, nothing could be further from the truth. A finding of ID only changes the methodology, the direction, the heuristic of further research; it doesn't end it.
For example, we return to the example of finding what appears to be an alien artifact on an apparently long-dead world we visit for the first time. If there is no scientifically valid means of first identifying the artifact as best explained as the product of ID, must we then limit our research to providing natural explanations for the artifact that preclude ID?
If so, why? Is ID not as natural as anything else in the world (see #6 above)? Why should it be excluded as an explanatory candidate?
Can we not attempt to reverse-engineer the artifact? Can we not speculate on design goals for different aspects or about what appear to be functional machines and devices in the artifact, the purpose of the arrangement and layout, the uses of what seems to be equipment, then test, experiment, and conduct research on such hypothesi?
There are entirely different research paradigms involved if the artifact is assumed to be generated by intelligence or if it is assumed to be the product of otherwise natural forces; if we assume it came together largely by chance and mindless, lawful necessity, or if we assume it was constructed with a purpose (or many such purposes) in mind.
Why should we assume either? Why not develop a scientifically rigorous methodology that can determine if something is best explained as product of ID or not?
This is precisely what ID theorists are currently striving to do, as well as to find such phenomena, and then to develop research programs of such phenomena based on the finding that they are intelligently designed.