Time’s Arrow, Time’s Cycle: Myth and Metaphor in the Discovery of Geological Time
“Is Uniformitarianism Necessary?”
“Punctuated Equilibria: An Alternative to Phyletic Gradualism,”
Ontogeny and Phylogeny
Ever Since Darwin: Reflections in Natural History
“The Spandrels of San Marcos and the Panglossian Paradigm: A Critique of the Adaptationist Programme,”
The Panda’s Thumb: More Reflections in Natural History
The Mismeasure of Man
Hen’s Teeth and Horse’s Toes
The Flamingo’s Smile: Reflections in Natural History
Ever since the appearance of Ontogeny and Phylogeny a decade ago, Stephen Jay Gould has continued to delight and inform a wide spectrum of readers and, in doing so, to defy C.P. Snow’s lament about the “two cultures” of the sciences and the humanities. Gould’s monthly column in Natural History magazine, published under the heading “This View of Life,” has led to a series of highly praised volumes of essays—Ever Since Darwin (1977), The Panda’s Thumb (1980), Hen’s Teeth and Horse’s Toes (1983), and most recently The Flamingo’s Smile (1985). In addition, Gould’s Mismeasure of Man (1981), which won the National Book Critics’ Circle Award, analyzed the questionable character of intelligence testing and emphasized the many personal and cultural biases that have led researchers astray in this field. Given the sheer amount of Gould’s publications, which include numerous scientific publications as well, Gould’s readers have been kept busy indeed absorbing his prodigious output.
Now, with Time’s Arrow, Time’s Cycle, Gould has turned to the history of geology, a field very close to his main concerns as a paleontologist. In this new work he offers a revisionist historical account of the discovery of geological time. If anyone suspects that Gould has at last written a book on a rather dry historical question, I should emphasize that he has hit upon a rich subject and has written a highly perceptive and fascinating book. Furthermore, his latest volume offers his readers a valuable insight into his wider intellectual vision, providing them with a literary blueprint for a number of the basic concerns that unite his many essays and books. To understand Gould one should read his new book. In this review I shall try to illustrate some of the connections between it and the rest of his work.
The Discovery of Deep Time
Geological time is so immense compared with the human experience of time that we can only hope to grasp it dimly through analogies. “Consider the earth’s history,” Gould suggests, “as the old measure of the English yard, the distance from the king’s nose to the tip of his outstretched hand. One stroke of a nail file on his middle finger erases human history.” This discovery of “deep time,” which involved abandoning biblical standards of time for nearly incomprehensible eons, Gould ranks with the monumental intellectual revolutions associated with Copernicus and Darwin. He has picked three major figures in the history of geology, one traditional villain (Thomas Burnet) and two traditional heroes (James Hutton and Charles Lyell), to illustrate the nature of this discovery.
Standard textbook accounts of the achievements of these three figures have long provided what Gould describes as a “self-serving mythology.” These flimsy “cardboard” accounts vaunt the superiority of empiricism and inductivism over the scientific nemesis of religious bigotry. According to the textbooks, geology remained in the service of the Mosaic story of creation as long as armchair geological theorists refused to place fieldwork ahead of scriptural authority. Thomas Burnet, author of the Sacred Theory of the Earth (1681–1689), was just such an archetypical spokesman for religious interests. A century later the Scottish geologist James Hutton finally broke with this biblical zealotry by arguing that geological evidence must rest upon a solid empirical foundation (literally, the rocks themselves) and that the earth’s strata, once carefully examined, betray “no vestige of a beginning—no prospect of an end.” But Hutton was far ahead of his time (and also not a very persuasive writer). It was therefore not until Charles Lyell published the Principles of Geology (1830–1833) that geologists finally came to accept Hutton’s basic message and banished miraculous intervention, catastrophes, and biblical deluges from their science.
Other historians of geology, Gould acknowledges, have refuted this textbook mythology, and he claims no originality in this respect. But he does believe that the real sources of inspiration in the discovery of deep time have not been properly understood. It is this aspect of the story that he sets out to rectify, and he does so with imagination and flair. In this respect Gould should be seen as part of the generation of historians who have been affected by T.S. Kuhn’s Structure of Scientific Revolutions (1962). Kuhn argued, in part, that science is a social activity and that theories are intellectual constructions imposed on data, not demanded by them. The views of Kuhn and other philosophers and sociologists of science have helped historians of science to recognize, as Gould emphatically does, that mental constructs (metaphors, analogies, personal philosophies, imaginative leaps)—not empirical discoveries—are what bring about scientific advance. “Facts” are so embedded in theory that they simply do not have the kind of independent probative power they were once supposed to possess.
Thus what underlies the discovery of deep time is by no means fieldwork, as the myths of geology textbooks would have us believe. Rather, Gould pinpoints a powerful pair of metaphors—time’s arrow and time’s cycle—by which humankind has always tried to grasp the concept of time. Time’s arrow captures the uniqueness and distinctive character of sequential events, whereas time’s cycle provides these events with another kind of meaning by evoking lawfulness and predictability. Gould notes that this metaphorical pair is common not only in the thinking of ancient and preliterate peoples but also in the Judeo-Christian tradition, in which time’s arrow nevertheless began to predominate. More importantly, this metaphorical pair of ideas was essential to the thinking of Gould’s three geological protagonists; and the paired concepts therefore offer the key, now obscured by textbook mythology, to unlocking their thinking about time.
Burnet and Newton
The frontispiece to Thomas Burnet’s Sacred Theory of the Earth embodies the essence of his argument. Christ, at the top, has his left foot on the earth as it was in the beginning of the creation (“without form and void”). Earth history moves clockwise, recording the perfect (featureless) earth of Eden, the Flood (with Noah’s ark floating just above the center), the present state of the earth, the coming conflagration that shall consume and purify the earth once more, and finally the earth transformed into a star after the righteous have ascended to heaven. Above Christ is the inscription from the Book of Revelation, “I am the alpha and omega,” that is, the beginning and the end. (See illustration on this page.)
Burnet’s theory illustrates the metaphors of time’s arrow and time’s cycle in unmistakable form. His is a one-cycle theory in which biblical narrative (time’s arrow) runs its course within a wider conception of “the great year” and “great circle of time and fate” that bring about the return of Paradise. It is precisely this literal belief in Scripture that has made Burnet a pariah in the history of geology. Yet Burnet, Gould demonstrates, was hardly the religious fanatic he is supposed to have been when he is placed within the context of contemporary scientific thought. Compared with the textbook legend, Burnet was, ironically, adamant about explaining the history of the earth as recorded in Scriptures entirely within the frame of natural science, devoid of all appeals to miracles or divine intervention. Whereas his contemporaries had to call upon God to create new and vast sources of water for the Flood, for example, Burnet tried to avoid such external interventions by positing an underground source of water released onto the earth’s surface through a fault in the crust. Similarly, Burnet believed that Vesuvius and Etna would provide the sources of fire that would ultimately consume and purify the world prior to the second coming of Christ.
In a revealing exchange, Burnet in 1681 argued with Isaac Newton over the length of the original “days” of creation. Newton saw a way out of the difficulty of assuming God had made the world in a week. He believed that the “days” of Genesis might have been much longer than present ones, and that God, when the job was finally done, intervened in order to speed up the earth’s rotation. Burnet regarded such a theory as totally unacceptable precisely because it required divine intervention. Thus the “bad guy” of geological textbook history was actually more devoted to rational, miraclefree science than the greatest scientist of his age.
Deep Time as Endless Cycles
Before James Hutton most geological theorists, working within a limited time scale for earth history, had dealt only with processes of decay. The earth was created, so their thinking went, and its geologic structures just wore down through catastrophic events like the biblical Flood and through more ordinary processes like weathering. Hutton’s genius was to introduce the concept of repair into geology and, with it, the notion of deep time. The textbooks, of course, see this as a triumph of science and empiricism over religion, but it was nothing of the kind. Ironically, Hutton’s entire theory of the earth was an a priori conception inspired jointly by religious considerations and “the most rigid and uncompromising version of time’s cycle ever developed by a geologist.”
Hutton’s theory grew out of a problem—what may be called “the paradox of the soil.” A gentleman farmer, Hutton was well aware that good soil, the product of the “denudation,” or eroding, of rock strata, eventually loses its richness to the plant life it sustains. Were there to be no geological source for continual new soil, Hutton believed, then the world would bear the intolerable stamp of an imperfectly designed abode for man’s existence. Hutton’s homocentric and teleological concept of the world therefore demanded that the soil, new soil, should never run out. This requirement in turn demanded the uplift of new strata to become the sources for soil replenishment. So Hutton, belatedly in his career, set out to find evidence for uplift (which he naturally did, since he was already looking for it). In fact, he found evidence for repeated uplifts of the earth’s crust. This realization led him inexorably to the discovery of deep time. In Hutton’s final theory the earth became an entirely self-regulating machine cycling its way, over and over again, through three geological stages: (1) denudation and decay; (2) the deposition of new marine strata; and (3) the melting, expansion, and uplift of the lowest strata as “igneous” rock ready to be broken down again for future plants. Hutton’s recognition that certain rocks had solidified from molten magma was a particularly powerful new insight.
So rigid was Hutton’s vision of an endlessly cycling earth having “no vestige of a beginning” and “no prospect of an end” that he lost all interest in the historical nature of geological change. The divine benevolence entailed in these cycles was everything to Hutton, who, in a Newtonian rather than a historical image, compared them to the planets revolving ceaselessly about the sun. “Through the thousand pages of Hutton’s treatise ,” Gould poignantly remarks, “we find not a single sentence that treats the different ages and properties of strata as interesting in themselves—as markers of distinction for particular times.”