AP Photo/Ed Reinke

Ken Ham, founder of Answers in Genesis, at the Creation Museum in Kentucky (AP Photo/Ed Reinke)

Once upon a time, in the West, sacred history, human history, and natural history were one. The Hebrew Bible, refracted through the prism of the Christian New Testament, told a story in which time, nature and humanity came into being together. From that beginning, history, with its low spots (Eve, the serpent, the apple) and its high marks (the birth, death, and resurrection of Jesus Christ) was the unfolding of God’s plan for the redemption of a fallen humanity. For Christians, time had a plot, and its beginning and end were both part of written history: even as its bright unfolding was traced in the opening chapters of the Book of Genesis, its ending in cataclysm, judgment, and eternal life was laid out in the Book of Revelation.

Humans were there from day six of creation, made by God in his image. Both free will and the moral and ethical understandings that allowed us to live in community with each other were grounded in divine creation: they were gifts of God. Nature was understood to be fitted to human use and to operate on something of a human scale. As this story was told in medieval Europe (roughly, the centuries between the fall of Rome and Columbus’s voyage to the lands that became the Americas) the earth was nested at the heart of the cosmos. Ringed around it were the moon, the planets, the sun, and the stars, all encompassed by the heaven where God reigned in majesty. We looked up from the center not at infinite space but at a mansion made of nested spheres spinning in perfect harmony.

Once upon a time, indeed. Though very few would argue any more that the earth is at the center of the cosmos, many find the notion that humanity is as old (or as young) as the earth to be a true, and immensely satisfying, story. According to the latest Gallup poll on this question, some 42 percent of Americans—a number that has hardly budged in over 30 years of surveys—claim to believe in young-earth Creationism. Drawing on the work of Biblical chronologists active in the sixteenth and seventeenth centuries, young-earth Creationists date the origins of the cosmos to roughly 6,000 years ago. Organizations like Answers in Genesis, whose director Ken Ham recently debated Bill Nye on the scientific merits of young earth creationism, defend it ardently.

Assenting to this vision of history requires a series of strategic denials. First and foremost for Ham and his organization is the denial that science, and scientists, can say anything at all about history. “Historical science” cannot be proved: no matter what geologists, biologists, and paleontologists might infer about the past by applying their knowledge of natural processes to the present conditions of the rocks, living organisms, and fossils, they were not physically present to witness the events their sciences explain. History is a thing written in a sacred book.

Yet Ham is not eager to deny science altogether: rather, he attempts to discredit “historical science” while preserving “observational science.” Observational science is responsible for the technological innovations that smooth modern life, a point Ham illustrated in his debate with Nye with a Powerpoint slide of an iPhone. Yet in attacking “historical science,” Ham (and Answers in Genesis more broadly) creatively appropriate scientific language and scientific methods. In doing so, they pay a backhand compliment to scientific modes of apprehending reality, suggesting that for all it appears to be under threat in this postmodern world, scientific ways of knowing the world remain our primary means of securing publicly shared knowledge.

Perhaps surprisingly to those of us weaned on the “two cultures” divide between the humanities and the sciences, many of the sciences—especially those that tend to invalidate literal readings of the book of Genesis—are fundamentally historical in nature. They read “the book of nature” in ways that are analogous to the ways in which historians read written documents and archaeologists ancient artifacts. If the earth is an archive, fossils, and even living species, with their information-rich genomes, are documents.

It was in the seventeenth and eighteenth centuries—at least two hundred years before Charles Darwin and his intervention into our understanding of the development of human life—that science first began to be historical. At that time, natural philosophers seriously began wondering what fossils were. Marine fossils posed a particular problem. Robert Plot, an English natural historian and museum curator, and others argued that they were naturally produced in rocks, “jokes of nature,” in which the rock mimicked organic forms. Others, the mechanical philosopher Robert Hooke among them, began to suspect that they were the remains of living animals. But, if they had once been living animals, how could it be that fossils of sea-dwellers were now found on dry plains and the tops of mountains? The naturalist John Woodward, reasoning from the shared understanding that natural, human, and sacred history were one, produced a sweeping theory that fit fossils into the unified, biblical history that he and his colleagues knew so well. Marine fossils in unusual places were natural evidence that confirmed the biblical story of the flood, which had swept across the earth, lifting ocean dwellers up to the highest heights and destroying everything and everyone except for Noah, his family, and the animals he packed on to the ark.

This debate was perhaps the closest thing the seventeenth century had to 2014’s “Ham on Nye”—with one exception. God was on both sides. Robert Plot promoted the “jokes of nature,” theory because he could not conceive of a mechanism that would move ocean animals to the tops of mountains and also accord with biblical history. Those on the other side, including Robert Hooke and Woodward, could not accept that God would create something so apparently purposeless as a rock that mimicked the form of a shell yet had never sheltered a soft bodied sea dweller. God was a being of loving and rational purpose; he did not play jokes on his human children.

Though both camps were trying to reconcile the evidence of nature to the biblical record, they each slung accusations of atheism at the other. Proponents of the “jokes of nature” theory were atheists because they seemed to deny that God operated in rational, purposeful ways that could be understood by human observers. Eyebrows were raised at Woodward, as well: in his theory, the flood was a product of natural laws. These natural laws were ordained by God. But still, Woodward’s flood was not a miracle—it did not involve God breaking into the world in violation of the laws of nature—and it just happened to coincide with a period of extraordinary human sinfulness, as required by the Genesis narrative.

In the short term, the diluvians won the day—most naturalists were persuaded that the spread of marine fossils was due to the biblical flood. The unified timeline of human, sacred, and natural history was preserved, as was the notion that nature was authored by a loving, rational God. Yet over the course of the eighteenth century, as fossil evidence became more fully integrated into a developing knowledge of geology, this explanation came to seem less and less satisfactory. The earth’s terrain, and the spread of the fossils in the layers of rock that cloaked the earth, were too varied to be explained by a single global flood. Geologists began to argue that there were no miraculous, global cataclysms. Rather, one could argue backward to the past from forces visible in the present—volcanoes erupted, spreading magma that hardened into rock, which wind and rain eroded, grinding it into soil. Rivers carved canyons and deposited silts. Glaciers gradually pushed great boulders immense distances.

But these processes were slow, so slow, that, to produce the earth as it now existed, they had to operate across many more centuries than the time scale allowed by the biblical story. Eighteenth century geologists largely refused to specify precisely how old the earth was, believing they had insufficient evidence to make such judgments, but they generally agreed that it was much older than the human race, possibly by as much as a million years (to a people that had previously agreed the world was about 6,000 years old, an almost unimaginable span of time). Yet, though they dramatically expanded natural history, setting human history adrift in a sea of time, many natural philosophers continued to believe that nature’s past was legible because the natural order was underwritten by God.

For Ken Ham, as for many young-earth creationists, the history of science stopped in 1700: Ham’s theory is essentially Woodward’s. Ham’s distinction between historical and observational science is not merely a curiosity: real harm is possible, for example, in that Answers in Genesis uses it to discredit the science behind global warming, which relies on reconstructing many millennia of climate history. Yet, living in the twenty-first century, Ken Ham is also forced to defend his distinction between historical and observational science in modern scientific terms. Answers in Genesis provides essay after essay dissecting the latest fossil finds, and explaining how geological evidence can be read in terms of a catastrophic flood. In order to do so, they delve deeply into the sciences of radiometric dating, fluid dynamics, stratigraphy, and even quantum mechanics. The question of whether Christians should “believe in ‘weird’ physics” (a category which, in the Answers in Genesis view, includes relativity, quantum mechanics, and string theory) animates a long, detailed essay on the history of physics. (Short answer: yes.)

Although a scientist might read Answers in Genesis’s engagement with scientific knowledge as disingenuous, it can have unpredictable effects—a curious reader might well find the detailed scientific explanations of geological phenomena more convincing than their rebuttal. Or, she might ask: if I’m allowed to accept quantum mechanics, why not radiometric dating, which relies on quantum mechanical understandings of the atom to establish the ages of human and fossil remains? Answers in Genesis also seeks to preserve the products of scientific and technical research that are integrated into our lives—in addition to that iPhone, the slides that Ken Ham threw up during the debate with Bill Nye included an image of Craig Venter, the lead scientist on the Human Genome Project. Venter may be an atheist, Ham admits, but he does good “observational science”—the kind that produces new medical breakthroughs that many rely upon. Yet analysis of the genome leads to enriched understandings of human evolutionary history, as well as new cancer treatments. Ham’s distinction between historical and observational science is incoherent, as Nye pointed out in their debate.

Yet it is also true that we owe the notion that fossils, rocks, and genomes are documents from which we can read nature’s history to a theological conception of nature. Seventeenth-century natural philosophers turned against the “jokes of nature” theory of fossils because they refused to believe that Nature’s God played tricks on humans. Their God was an author, one who wrote a Book of Nature that humans were meant to be able to read. Modern science (as a matter of general methodological principle—this is to say nothing of the beliefs of individual scientists) may have declared the divine author dead, yet a way of divinely-inspired reading continues on in the belief that nature operates according to rational laws that humans can decipher. That assumption is so fundamental that, for scientists, it is an article of faith.

Elizabeth Yale is an historian of science and adjunct assistant professor at The University of Iowa Center for the Book.