The Gene: An Intimate History - Siddhartha Mukherjee Page 0,13

watch lying on the ground. He picks up the instrument and opens it to find an exquisite system of cogs and wheels turning inside, resulting in a mechanical device that is capable of telling time. Would it not be logical to assume that such a device could only have been manufactured by a watchmaker? The same logic had to apply to the natural world, Paley reasoned. The exquisite construction of organisms and human organs—“the pivot upon which the head turns, the ligament within the socket of the hip joint”—could point to only one fact: that all organisms were created by a supremely proficient designer, a divine watchmaker: God.

The second book, A Preliminary Discourse on the Study of Natural Philosophy, published in 1830 by the astronomer Sir John Herschel, suggested a radically different view. At first glance, the natural world seems incredibly complex, Herschel acknowledged. But science can reduce seemingly complex phenomena into causes and effects: motion is the result of a force impinging on an object; heat involves the transference of energy; sound is produced by the vibration of air. Herschel had little doubt that chemical, and, ultimately, biological phenomena, would also be attributed to such cause-and-effect mechanisms.

Herschel was particularly interested in the creation of biological organisms—and his methodical mind broke the problem down to its two basic components. The first was the problem of the creation of life from nonlife—genesis ex nihilo. Here, he could not bring himself to challenge the doctrine of the divine creation. “To ascend to the origin of things, and speculate on creation, is not the business of the natural philosopher,” he wrote. Organs and organisms might behave according to the laws of physics and chemistry—but the genesis of life itself could never be understood through these laws. It was as if God had given Adam a nice little laboratory in Eden, but then forbidden him from peering over the walls of the garden.

But the second problem, Herschel thought, was more tractable: Once life had been created, what process generated the observed diversity of the natural world? How, for instance, did a new species of animal arise from another species? Anthropologists, studying language, had demonstrated that new languages arose from old languages through the transformation of words. Sanskrit and Latin words could be traced back to mutations and variations in an ancient Indo-European language, and English and Flemish had arisen from a common root. Geologists had proposed that the current shape of the earth—its rocks, chasms, and mountains—had been created by the transmutation of previous elements. “Battered relics of past ages,” Herschel wrote, “contain . . . indelible records capable of intelligible interpretation.” It was an illuminating insight: a scientist could understand the present and the future by examining the “battered relics” of the past. Herschel did not have the correct mechanism for the origin of species, but he posed the correct question. He called this the “mystery of mysteries.”

Natural history, the subject that gripped Darwin at Cambridge, was not particularly poised to solve Herschel’s “mystery of mysteries.” To the fiercely inquisitive Greeks, the study of living beings had been intimately linked to the question of the origin of the natural world. But medieval Christians were quick to realize that this line of inquiry could only lead to unsavory theories. “Nature” was God’s creation—and to be safely consistent with Christian doctrine, natural historians had to tell the story of nature in terms of Genesis.

A descriptive view of nature—i.e., the identification, naming, and classification of plants and animals—was perfectly acceptable: in describing nature’s wonders, you were, in effect, celebrating the immense diversity of living beings created by an omnipotent God. But a mechanistic view of nature threatened to cast doubt on the very basis of the doctrine of creation: to ask why and when animals were created—by what mechanism or force—was to challenge the myth of divine creation and edge dangerously close to heresy. Perhaps unsurprisingly, by the late eighteenth century, the discipline of natural history was dominated by so-called parson-naturalists—vicars, parsons, abbots, deacons, and monks who cultivated their gardens and collected plant and animal specimens to service the wonders of divine Creation, but generally veered away from questioning its fundamental assumptions. The church provided a safe haven for these scientists—but it also effectively neutered their curiosity. The injunctions against the wrong kinds of investigation were so sharp that the parson-naturalists did not even question the myths of creation; it was the perfect separation of church and mental state. The result was a peculiar distortion of