Two major, closely related scientific objections to Intelligent Design theory have always been that 1) you can't directly observe an intelligent designer or its purported creative process, and 2) you can't design legitimate experiments that will test for intelligent design. These two drawbacks are presumed by mainstream scientists to place the theory definitively outside the realm of science.
In the latest in his series of counterthrusts to John Derbyshire's Darwinist attack, Jonathan Witt quotes at length from an online chapter of a book, Science and Evidence of Design in the Universe, by Stephen C. Meyer, a Ph.D. in the history and philosophy of science who is director and Senior Fellow of the Center for Science and Culture at the Discovery Institute in Seattle.
Before you read further, note that Discovery and CSC are notorious in the mainstream scientific world as well-funded, nested think tanks frankly promoting what many scientists regard as an oxymoron -- a scientific alternative to philosophical materialism. An exposé of its "hidden agenda" is here. This blog would be regarded as an unwitting tool of "Phase II." I believe that my eyes and my mind are open, and that the fact that "evolutionary theory [now] enjoys nearly unanimous support in the scientific community" is no reason not to question it -- in fact, is a good reason to question it, given the ultimate fate of many other such consenses (consensi?) in the past. I do not want to regard either neo-Darwinism or Intelligent Design as substantially proven without more undeniable evidence. That this is actually a tall order for Darwinism is the uncomfortable point I think IDers have succeeded in making. (Mark Perakh at Talk Reason says I'm wrong.) That it is an even taller order for Intelligent Design is the assertion that Witt and Meyer seek to refute.
Here's Meyer's argument:
[O]bservability at least is not necessary to scientific status, as theoretical physics has abundantly demonstrated. Many entities and events cannot be directly observed or studied in practice or in principle. The postulation of such entities is no less the product of scientific inquiry for that. Many sciences are in fact directly charged with the job of inferring the unobservable from the observable. Forces, fields, atoms, quarks, past events, mental states, subsurface geological features, molecular biological structures all are unobservables inferred from observable phenomena. Nevertheless, most are unambiguously the result of scientific inquiry.
Second, unobservability does not preclude testability: claims about unobservables are routinely tested in science indirectly against observable phenomena. That is, the existence of unobservable entities is established by testing the explanatory power that would result if a given hypothetical entity (i.e., an unobservable) were accepted as actual. . . . [M]any scientific theories must be evaluated indirectly by comparing their explanatory power against competing hypotheses. . . .
Such attempts to infer to the best explanation, where the explanation presupposes the reality of an unobservable entity, occur frequently in many fields already regarded as scientific, including physics, geology, geophysics, molecular biology, genetics, physical chemistry, cosmology, psychology and, of course, evolutionary biology.
The prevalence of unobservables in such fields raises difficulties for defenders of descent who would use observability criteria to disqualify design. Darwinists have long defended the apparently unfalsifiable nature of their theoretical claims by reminding critics that many of the creative processes to which they refer occur at rates too slow to observe. . . . The transitional life forms that ostensibly occupy the nodes on Darwin's branching tree of life are unobservable, just as the postulated past activity of a Designer is unobservable. . . . Darwinian transitionals, neo-Darwinian mutational events, punctuationalism’s "rapid branching" events, the past action of a designing agent—none of these are directly observable.
On the more difficult question of testability, Meyer again sets out to demonstrate that the theory of evolution has no intrinsic advantage over the theory of intelligent design. He quotes Darwin himself as freely admitting that his theory of descent with modification is not directly testable, but could be indirectly tested by comparing its power to explain observable phenomena to the explanatory power of competing theories.
Meyer quotes Columbia University philosopher of science Philip Kitcher, "no friend of creationism," acknowledging that "Even postulating an unobserved Creator need be no more unscientific than postulating unobserved particles. What matters is the character of the proposals and the ways in which they are articulated and defended."
And that's how it ends: in a draw (almost an anagram for "Darwin"!), with proponents of each theory claiming that theirs has greater explanatory power over the tangible evidence of unobservable past events. Darwinism has the advantage that "microevolution" -- changes in the predominant characteristics of a population in response to environmental shifts -- is observable. Intelligent Design theorists don't deny that it is. What they deny is that there is remotely enough evidence to make the conceptual leap to "macroevolution" -- the origin of complex cellular mechanisms, of animal phyla, of life itself.
Some -- OK, I -- speculate that, as early hominids grew older and could no longer effectively hunt or make war, they developed a snore, which scared off nocturnal predators. Unfortunately, it also scares off mates, tree squirrels, birds, in fact, every living thing for hundreds of miles. Early snorers would awake to find that their snore had turned their plentiful biosphere into an ecological wasteland. Again, I ask: how Intelligent could such a Design be?
UPDATE II: Hey, what if we find out we were intelligently designed, and she was from Alpha Centauri? Have these guys thought of that??