Why intelligent design isn't so intelligent

Scientific American has a highly readable article today that serves to rebut the claims of creationists, intelligent design advocates and other "skeptics" who question the primacy of evolutionary theory. I particularly like the way it's organized by the types of arguments raised by the anti-evolution set. There's also a nice little roundup of just why intelligent design is such a specious argument against the overwhelming scientific evidence of evolution:

"Creation science" is a contradiction in terms. A central tenet of modern science is methodological naturalism--it seeks to explain the universe purely in terms of observed or testable natural mechanisms. Thus, physics describes the atomic nucleus with specific concepts governing matter and energy, and it tests those descriptions experimentally. Physicists introduce new particles, such as quarks, to flesh out their theories only when data show that the previous descriptions cannot adequately explain observed phenomena. The new particles do not have arbitrary properties, moreover--their definitions are tightly constrained, because the new particles must fit within the existing framework of physics.

In contrast, intelligent-design theorists invoke shadowy entities that conveniently have whatever unconstrained abilities are needed to solve the mystery at hand. Rather than expanding scientific inquiry, such answers shut it down. (How does one disprove the existence of omnipotent intelligences?)

Intelligent design offers few answers. For instance, when and how did a designing intelligence intervene in life's history? By creating the first DNA? The first cell? The first human? Was every species designed, or just a few early ones? Proponents of intelligent-design theory frequently decline to be pinned down on these points. They do not even make real attempts to reconcile their disparate ideas about intelligent design. Instead they pursue argument by exclusion--that is, they belittle evolutionary explanations as far-fetched or incomplete and then imply that only design-based alternatives remain.