Earlier this week, young-earth creationist Ken Ham and “Science Guy” Bill Nye engaged in a well-publicized debate at the Creation Museum in Kentucky. It was generally been framed as a contest between science and religion — or, as Mark Joseph Stern suggested at Slate, “Science vs. Fiction.” Even televangelist Pat Robertson weighed in to tell Ham that his young-earth creationism was not just false, but humiliatingly stupid. "To say that it all came about in 6000 years is just nonsense," Robertson said on his show, The 700 Club. " Let’s be real, let’s not make a joke of ourselves."
Creationism continues to have currency among a significant proportion of the American public, even though it has never had any scientific basis. The ferocity of the debate makes it difficult to remember that, at one point not so long ago in geological time, religion and science weren't all that distinct. In the late 1600s and early 1700s, intelligent design — the belief that you could find God's hand by examining creation — was seen as a way to glorify both God and the ordered laws of physics revealed by Newton.
The most sophisticated form of the intelligent design argument, however, wasn't based on Newtonian physics. It was based in biology. In 1802, a theologian named William Paley published his tome Natural Theology. Hume had shot largish holes in the Newtonian design argument, and Paley as a consequence granted that astronomy was "not the best medium through which to prove the agency of an intelligent Creator." But, he argued, it was still possible to see purpose in the universe by looking to animal and human life.
Each creature, Paley argued, was uniquely shaped to its environment in a way that showed a kind of intimate care. Moles have feet that function as "so many shovels," to allow them to dig through the earth. "Maggots" are perfectly equipped to "revel in putrefaction." The human "gall-duct into the duodenum" is structured to have "a necessary mechanical tendency to resist regurgitation." Animals are adapted so that their sleep cycles fit into the movement of day and night, a fact which for Paley "connects the meanest individual with the universe itself: a chicken roosting upon its perch, with the spheres revolving in the firmament."
It's easy to laugh at Paley's enthusiasms; he was probably laughing at them himself to some extent. (I have to believe he chuckled a little at that bit about maggots reveling in putrefaction.) But while his reasoning can appear amusing in retrospect, Natural Theology was a hugely important work, not only for its own day, but for ours. The way Paley formulated the design argument essentially split God in two: there was a lawgiver, who set in place the physical universe and the motion of the spheres, and there was a creator, who shaped individual creatures, whether humans or chickens roosting on their perches, to fit those laws. As John Durant wrote in Darwinism and Divinity: Essays on Evolution and Religious Belief, "by pushing God Himself into the background, and entrusting the enforcement of the 'rules of creation' to an intelligent subordinate ... Paley unwittingly transformed his defence of theism into a model of naturalistic explanation."
That "naturalistic explanation" is only a step away from Darwin's natural selection. And, in fact, it probably is a version of natural selection, in that there's every reason to believe that Darwin was informed by Paley's work. Paley's books were used extensively in the undergraduate curriculum at Christ's College (Paley's college as well as Darwin's), and Darwin remembered them fondly in his autobiography. It shouldn't be surprising, then, that the questions Darwin was answering were ones that Paley had posed, and the observations he was making were ones that Paley had developed. Intelligent design wasn't something invented after Darwin to oppose him; rather, it was the context for, and a building block of, his work.