Time's Arrow, Time's Cycle

Myth and Metaphor in the Discovery of Geological Time

Stephen Jay Gould

• Publisher: Harvard University Press
• Year: 1988
• ISBN:
  9780674263987
• Topic: Naturwissenschaften
• Subtopic: Geologie & Geowissenschaften

Rarely has a scholar attained such popular acclaim merely by doing what he does best and enjoys most. But such is Stephen Jay Gould's command of paleontology and evolutionary theory, and his gift for brilliant explication, that he has brought dust and dead bones to life, and developed an immense following for the seeming arcana of this field.In Time's Arrow, Time's Cycle his subject is nothing less than geology's signal contribution to human thought—the discovery of "deep time, " the vastness of earth's history, a history so ancient that we can comprehend it only as metaphor. He follows a single thread through three documents that mark the transition in our thinking from thousands to billions of years: Thomas Burnet's four-volume Sacred Theory of the Earth (1680–1690), James Hutton's Theory of the Earth (1795), and Charles Lyell's three-volume Principles of Geology (1830–1833).Gould's major theme is the role of metaphor in the formulation and testing of scientific theories—in this case the insight provided by the oldest traditional dichotomy of Judeo-Christian thought: the directionality of time's arrow or the immanence of time's cycle. Gould follows these metaphors through these three great documents and shows how their influence, more than the empirical observation of rocks in the field, provoked the supposed discovery of deep time by Hutton and Lyell. Gould breaks through the traditional "cardboard" history of geological textbooks (the progressive march to truth inspired by more and better observations) by showing that Burnet, the villain of conventional accounts, was a rationalist (not a theologically driven miracle-monger) whose rich reconstruction of earth history emphasized the need for both time's arrow (narrative history) and time's cycle (immanent laws), while Hutton and Lyell, our traditional heroes, denied the richness of history by their exclusive focus upon time's arrow.

CHAPTER ONE

The Discovery of Deep Time

Deep Time

Sigmund Freud remarked that each major science has made one signal contribution to the reconstruction of human thought—and that each step in this painful progress had shattered yet another facet of an original hope for our own transcendent importance in the universe:

Humanity has in course of time had to endure from the hand of science two great outrages upon its naive self-love. The first was when it realized that our earth was not the center of the universe, but only a speck in a world-system of a magnitude hardly conceivable … The second was when biological research robbed man of his particular privilege of having been specially created and relegated him to a descent from the animal world.

(In one of history’s least modest pronouncements, Freud then stated that his own work had toppled the next, and perhaps last, pedestal of this unhappy retreat—the solace that, though evolved from a lowly ape, we at least possessed rational minds.)

But Freud omitted one of the greatest steps from his list, the bridge between spatial limitation of human dominion (the Galilean revolution), and our physical union with all “lower” creatures (the Darwinian revolution). He neglected the great temporal limitation imposed by geology upon human importance—the discovery of “deep time” (in John McPhee’s beautifully apt phrase). What could be more comforting, what more convenient for human domination, than the traditional concept of a young earth, ruled by human will within days of its origin. How threatening, by contrast, the notion of an almost incomprehensible immensity, with human habitation restricted to a millimicrosecond at the very end! Mark Twain captured the difficulty of finding solace in such fractional existence:

Man has been here 32,000 years. That it took a hundred million years to prepare the world for him is proof that that is what it was done for. I suppose it is, I dunno. If the Eiffel Tower were now representing the world’s age, the skin of paint on the pinnacle-knob at its summit would represent man’s share of that age; and anybody would perceive that that skin was what the tower was built for. I reckon they would, I dunno.

Charles Lyell expressed the same theme in more somber tones in describing James Hutton’s world without vestige of a beginning or prospect of an end. This statement thus links the two traditional heroes of deep time in geology—and also expresses the metaphorical tie of time’s new depth to the breadth of space in Newton’s cosmos:

Such views of the immensity of past time, like those unfolded by the Newtonian philosophy in regard to space, were too vast to awaken ideas of sublimity unmixed with a painful sense of our incapacity to conceive a plan of such infinite extent. Worlds are seen beyond worlds immeasurably distant from each other, and beyond them all innumerable other systems are faintly traced on the confines of the visible universe. (Lyell, 1830, 63)¹

Deep time is so difficult to comprehend, so outside our ordinary experience, that it remains a major stumbling block to our understanding. Theories are still deemed innovative if they simply replace a false extrapolation with a proper translation of ordinary events into time’s vastness. The theory of punctuated equilibrium, proposed by Niles Eldredge and myself, is not, as so often misunderstood, a radical claim for truly sudden change, but a recognition that ordinary processes of speciation, properly conceived as glacially slow by the standard of our own life-span, do not translate into geological time as long sequences of insensibly graded intermediates (the traditional, or gradualistic, view), but as geologically “sudden” origins at single bedding planes.

An abstract, intellectual understanding of deep time comes easily enough—I know how many zeroes to place after the 10 when I mean billions. Getting it into the gut is quite another matter. Deep time is so alien that we can really only comprehend it as metaphor. And so we do in all our pedagogy. We tout the geological mile (with human history occupying the last few inches); or the cosmic calendar (with Homo sapiens appearing but a few moments before Auld Lang Syne). A Swedish correspondent told me that she set her pet snail Björn (meaning bear) at the South Pole during the Cambrian period and permits him to advance slowly toward Malmö, thereby visualizing time as geography. John McPhee has provided the most striking metaphor of all (in Basin and Range): Consider the earth’s history 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.

How then did students of the earth make this cardinal transition from thousands to billions? No issue can be more important in our quest to understand the history of geological thought.

Myths of Deep Time

Parochial taxonomies are a curse of intellectual life. The acceptance of deep time, as a consensus among scholars, spans a period from the mid-seventeenth through the early nineteenth centuries. As Rossi wrote (1984, ix) : “Men in Hooke’s times had a past of six thousand years; those of Kant’s times were conscious of a past of millions of years.” Since geology didn’t exist as a separate and recognized discipline during these crucial decades, we cannot attribute this cardinal event of intellectual history to an examination of rocks by one limited fraternity of earth scientists. Indeed, Rossi (1984) has argued persuasively that the discovery of deep time combined the insights of those we would now call theologians, archaeologists, historians, and linguists—as well as geologists. Several scholars, in this age of polymathy, worked with competence in all these areas.

In limiting my own discussion to men later appropriated by professional geologists as their own predecessors, I consciously work within the framework that I am trying to debunk (or enlarge). I am, in other words, treating the standard stories accepted by geologists for the discovery of time. Professional historians have long recognized the false and cardboard character of this self-serving mythology—and I make no claim for originality in this respect—but their message has not seeped through to working scientists, or to students.

My parochiality extends even further—to geography as well as discipline. For I have selected for intensive discussion only the three cardinal actors on the British geological stage—the primary villain and the two standard heroes.

The temporal order of these men also expresses the standard mythology about the discovery of time. Thomas Burnet, villain by taint of theological dogmatism, wrote his Sacred Theory of the Earth in the 1680s. The first hero, James Hutton, worked exactly a century later, writing his initial version of the Theory of the Earth in the 1780s. Charles Lyell, second hero and codifier of modernity, then wrote his seminal treatise, Principles of Geology, just fifty years later, in the 1830s. (Science, after all, does progress by acceleration, as this halving of temporal distance to truth suggests.)

The standard mythology embodies a tradition that historians dismiss with their most contemptuous label—whiggish, or the idea of history as a tale of progress, permitting us to judge past figures by their role in fostering enlightenment as we now understand it. In his Whig Interpretation of History (1931), Herbert Butterfield deplores the strategy of English historians allied with the Whig party who wrote the history of their nation as a progressive approach to their political ideals:

The sin in historical composition … is to abstract events from their context and set them up in implied comparison with the present day, and then to pretend that by this “the facts” are being allowed to “speak for themselves.” It is to imagine that history as such … can give us judgments of value—to assume that this ideal or that person can be proved to have been wrong by the mere lapse of time. (105–106)

Whiggish history has a particularly tenacious hold in science for an obvious reason—its consonance with the cardinal legend of science. This myth holds that science differs fundamentally from all other intellectual activity in its primary search to discover and record the facts of nature. These facts, when gathered and refined in sufficient number, lead by a sort of brute-force inductivism to grand theories that unify and explain the natural world. Science, therefore, is the ultimate tale of progress—and the motor of advance is empirical discovery.

Our geological textbooks recount the discovery of deep time in this whiggish mode, as a victory of superior observation finally freed from constraining superstition. (Each of my subsequent chapters contains a section on such “textbook cardboard,” as I call it.) In the bad old days, before men rose from their armchairs to look at rocks in the field, biblical limitations of the Mosaic chronology precluded any understanding of our earth’s history. Burnet represented this antiscientific irrationalism, so well illustrated by the improper inclusion of “sacred” in his titular description of our planet’s history. (Never mind that he got into considerable trouble for his allegorical interpretation of the “days” of Genesis as potentially long ages.) Burnet therefore represents the entrenched opposition of church and society to the new ways of observational science.

Hutton broke through these biblical strictures because he was willing to place field observation before preconception—speak to the earth, and it shall teach thee. Two key Huttonian observations fueled the discovery of deep time—first, the recognition that granite is an igneous rock, representing a restorative force of uplift (so that the earth may cycle endlessly, rather than eroding once into ruin); and, second, the proper interpretation of unconformities as boundaries between cycles of uplift and erosion (providing direct evidence for episodic renewal rather than short and unilinear decrepitude).

But the world was not ready for Hutton (and he was too lousy a writer to persuade anyone anyway). Thus, the codification of deep time awaited the great textbook of Charles Lyell, Principles of Geology (1830–1833). Lyell triumphed by his magisterial compendium of factual information about rates and modes of current geological processes—proving that the slow and steady operation of ordinary causes could, when extended through deep time, produce all geological events (from the Grand Canyon to mass extinctions). Students of the earth could now reject the miraculous agents that compression into biblical chronology had required. The discovery of deep time, in this version, becomes one of history’s greatest triumphs of observation and objectivity over preconception and irrationalism.

Like so many tales in the heroic mode, this account of deep time is about equally long on inspiration and short on accuracy. Twenty-five years after N. R. Hanson, T. S. Kuhn, and so many other historians and philosophers began to map out the intricate interpenetrations of fact and theory, and of science and society, the rationale for such a simplistic one-way flow from observation to theory has become entirely bankrupt. Science may differ from other intellectual activity in its focus upon the construction and operation of natural objects. But scientists are not robotic inducing machines that infer structures of explanation only from regularities observed in natural phenomena (assuming, as I doubt, that such a style of reasoning could ever achieve success in principle). Scientists are human beings, immersed in culture, and struggling with all the curious tools of inference that mind permits—from metaphor and analogy to all the flights of fruitful imagination that C. S. Peirce called “abduction.” Prevailing culture is not always the enemy identified by whiggish history—in this case the theological restrictions on time that led early geologists to miracle-mongering in the catastrophist mode. Culture can potentiate as well as constrain—as in Darwin’s translation of Adam Smith’s laissez-faire economic models into biology as the theory of natural selection (Schweber, 1977). In any case, objective minds do not exist outside culture, so we must make the best of our ineluctable embedding.

It is important that we, as working scientists, combat these myths of our profession as something superior and apart. The myths may serve us well in the short and narrow as rationale for a lobbying strategy—give us the funding and leave us alone, for we know what we’re doing and you don’t understand anyway. But science can only be harmed in the long run by its self-proclaimed separation as a priesthood guarding a sacred rite called the scientific method. Science is accessible to all thinking people because it applies universal tools of intellect to its distinctive material. The understanding of science—one need hardly repeat the litany—becomes ever more crucial in a world of biotechnology, computers, and bombs.

I know no better way to illustrate this ecumenicism of creative thought than the debunking (in a positive mode) of remaining cardboard myths about science as pure observation and applied logic, divorced from realities of human creativity and social context. The geological myth surrounding the discovery of deep time may be the most persistent of remaining legends.

This book respects the defined boundaries of the myth to disperse it from within. I analyze in detail the major texts of three leading actors (one villain, two heroes), trying to find a key that will unlock the essential visions of these men—visions lost by a tradition that paints them as enemies or avatars of progress in observation. I find this key in a dichotomy of metaphors that express conflicting views about the nature of time. Burnet, Hutton, and Lyell all struggled with these ancient metaphors, juggling and juxtaposing until they reached distinctive views about the nature of time and change. These visions fueled the discovery of deep time as surely as any observation of rocks and outcrops. The interplay of internal and external sources—of theory informed by metaphor and observation constrained by theory—marks any major movement in science. We can grasp the discovery of deep time when we recognize the metaphors underlying several centuries of debate as a common heritage of all people who have ever struggled with such basic riddles as direction and immanence.

On Dichotomy

Any scholar immersed in the details of an intricate problem will tell you that its richness cannot be abstracted as a dichotomy, a conflict between two opposing interpretations. Yet, for reasons that I do not begin to understand, the human mind loves to dichotomize—at least in our culture, but probably more generally, as structuralist analyses of non-Western systems have demonstrated. We can extend our own tradition at least to the famous aphorism of Diogenes Laertius: “Protagoras asserted that there were two sides to every question, exactly opposite to each other.”

I used to rail against these simplifications, but now feel that another strategy for pluralism might be more successful. I despair of persuading people to drop the familiar and comforting tactic of dichotomy. Perhaps, instead, we might expand the framework of debates by seeking other dichotomies more appropriate than, or simply different from, the conventional divisions. All dichotomies are simplifications, but the rendition of a conflict along differing axes of several orthogonal dichotomies might provide an amplitude of proper intellectual space without forcing us to forgo our most comforting tool of thought.

The problem is not so much that we are driven to dichotomy, but that we impose incorrect or misleading divisions by two upon the world’s complexity. The inadequacy of some dichotomies rests upon their anachronism. Darwin, for example, built such a prominent watershed that we tend to impose the conventional dichotomy of his achievement—evolution versus creation—backward into time, forcing it upon different debates about other vital subjects. Examples are legion, and I have treated several in my essays—from a rampant precursoritis that tries to find Darwinian seeds in Greek thought; to the search for evolutionary tidbits in pre-Darwinian works, leading us to ignore, for example, an extensive and subtle treatise about embryology for a fleeting passage about change (see Gould, 1985, on Maupertuis); to the miscasting as creationist of a great tradition in structural biology (from Geoffroy Saint-Hilaire to Richard Owen) because its theory of change denied an environmental underpinning and therefore seemed antievolutionary to some who equated transmutation itself with later views about its mechanisms (Gould, 1986b, on Richard Owen).

Other misleading dichotomies are mired in the tradition of whiggish history in science, including the divisions that have so badly miscast the history of geology and its discovery of deep time: uniformitarianism/catastrophism, empiricist/speculator, reason/revelation, true/false. Lyell, as we shall see, established much of the rhetoric for these divisions, but we have been led astray by following him uncritically.

I do not wish to argue that other dichotomies are “truer.” Dichotomies are useful or misleading, not true or false. They are simplifying models for organizing thought, not ways of the world. Yet I believe, for reasons I shall outline in the next section, that one neglected dichotomy about the nature of time has particular value in unlocking the visions of my three key actors in the drama of deep time.

All great theories are expansive, and all notions so rich in scope and implication are underpinned by visions ab...