While Cardinal Schoenborn and the Roman Catholic Church's astronomer have officially indicated that it is possible to accept the science of evolution while remaining in good standing with the Church, the idea of intelligent design persists in at least this nation's conversation as a challenge to that claim. And there is less clarity in those discussions than in official pronouncements from a Cardinal and his Church.

In Kansas City, Missouri, earlier this year, a talk about intelligent design drew, among others, an attentive cohort of backbench listeners who serve as teaching assistants in introductory biology courses at the University of Kansas in Lawrence. They had driven approximately a hundred miles to hear how a theologian would talk about evolution and intelligent design. During the ensuing discussion they explained that "we get asked about this all the time in class, and we don't really know what to say." Their undergraduate charges want to know why the class does not include discussion of intelligent design as an alternative theory of the origins of life. The teaching assistants—Ph.D. students in biology—report that citing the series of decisive court decisions to the contrary is insufficient to the challenge.

In part, this is simply a tribute to the cleverness of the Discovery Institute, the prominent think tank largely responsible for shifting the terminology around this ongoing discussion from "creationism" to "intelligent design." In doing so, the Institute implies that its position is identical with one of the oldest and most popular arguments in the Christian tradition for the existence of God. And while creationism was decisively discredited by the courts in the 1980's, intelligent design retains a tenacious hold on the discourse, despite Judge John Jones's opinion in the 2005 Dover case.

Intelligent design will maintain this hold until more theologians become involved in the discussion. Exemplary precedent in this regard can be found in Langdon Gilkey's testimony in the 1981 creationism trial, McClean et al. v. Arkansas Board of Education, the case that reviewed Act 591 of the Arkansas State Legislature, which mandated the co-teaching of "creation science" and "evolution science" in the public schools. Judge William Overton's decision in McClean to invalidate Act 591 on grounds quite similar to those of Judge Jones—the Act constituted an establishment of religion, and thus violated the separation of church and state—drew centrally from Gilkey's distinction during the trial between questions of our ultimate origins, which are theological, and questions of our proximate origins, which are scientific.

Gilkey's testimony addressed the creationist position, but his distinction can usefully be extended to the debates about intelligent design, as follows: Scientists can opine about religion, and religious believers can opine about science—but each needs to recognize that in doing so, the grounds of the discussion shift. So when the eminent biologist Richard Dawkins argues, on the grounds of his exemplary science, that no thinking person can reasonably maintain that God exists, he is confusing scientific demonstration for theological claim. Similarly, when creationists argue that Genesis 1 and 2 should be included in the biology curriculum of public schools as an alternative scientific theory of origins, they are confusing theological claim with scientific theory.

Behind this distinction is a fact inconvenient to the proponents of intelligent design: Their term takes its basis from what is the most popularly recognized but philosophically dubious formulation of the teleological argument for the existence of God. This is the presentation of William Paley, who argued in his Natural Theology (1800) that a hiker who came upon a watch on the ground and opened it would discover its intricate mechanism and conclude that the watch's design reflected a designer. By analogy, Paley argued, we can look at the world and see evidence of a Designer who is God. The difficulty here, perhaps most trenchantly formulated by David Hume, is that an argument from experience cannot explain something—in this case, God—which is beyond experience and thus beyond causation.

The elegance of Gilkey's distinction is that it inserts an intellectual traffic cop at the hectic public intersection where science and religion meet. This intersection has the potential to be an interesting, busy, and important place, and it is regrettable that first "creationism" and now "intelligent design" have caused such traffic jams there.

Richard A. Rosengarten is Dean and Associate Professor of Religion and Literature at the University of Chicago Divinity School.