1. In economics, the distinguished columnist David Warsh used punctuated equilibrium to illuminate episodic change and long plateaus in the history of markets and prices (“What goes up sometimes levels off,” Boston Globe, 1990, and a good epitome for stasis vs. progressivism), and also to support the general concept of punctuational change at all levels, in a defense of capitalism with the ironic title “Redeeming Karl Marx” (Boston Globe, May 3, 1992). In a recent bestselling book, The Future of Capitalism, MIT economist Lester Thurow centered his argument upon two concepts borrowed from the evolutionary and geological sciences — punctuated equilibrium and plate tectonics (see further comment on pp. 964–966).
2. In political theory, the scholarly book of Carmines and Stimson (1989) argues for an episodic model of change based on case studies of the New Deal and race relations in America. “Dynamic evolutions,” they write (1989, p. 157), “thus represent the political equivalent of biology's punctuated equilibrium.” [Page 978]
3. In sociology, Savage and Lombard's (1983) model “of the process of change in the structure of work groups” cites a key prod from punctuated equilibrium:
Social scientists, at least in small-group studies, generally follow the uniformitarians' view. In recent years studies in several fields have led to revisions in arguments about these classic views. Paleobiology . . . continues to provide some of the most specific and convincing of the newer studies. Even though the field is far removed from the study of changes in work groups in South America, it is informative to examine some of them. Writing in 1972 about the fossil record of mollusks, Eldredge and Gould concluded that in the development of a new species “the alternative picture [to gradual and continuous change is] of stasis punctuated by episodic events.”
4. In history, Levine (1991) used our term and concept to center his argument about the history of working-class families in an article entitled: “Punctuated Equilibrium: The modernization of the proletarian family in the age of ascendant capitalism.”
5. In literary criticism, Moretti (1996) cited punctuated equilibrium to epitomize the history of the epic as a literary genre, the principal subject of his book: “It is an undulating curve; a discontinuous history that soars, then gets stuck. Overall, it is the conception illustrated by Gould and Eldredge with the theory of 'punctuated equilibria'” (Moretti, 1996, p. 75).
6. In art history, Bahn and Vertut (1988) used punctuated equilibrium to refute the standard gradualist and progressivist views of the greatest scholars of Paleolithic cave painting, the Abbe H. Breuil and Andre Leroi-Gourhan (see further comments on pp. 953–956).
7. In the dubious, but popular, literature of “self help” Connie Gersick's fascinating and thought-provoking work (see pp. 958–959) links individual and organizational growth to patterns of punctuated equilibrium. But her subtlety was badly sandbagged in the news bulletin of the University of California (where she teaches at UCLA) for February 21, 1989: “Gersick likened this transition to a midlife crisis, which, she said, is part of a phenomenon known as 'punctuated equilibrium' . . . For organizations which rely on the results of creative efforts, Gersick notes that understanding the transitions within the creative process can help groups to work more effectively. 'Managers may be able to build more punctuation points into the process.'”
8. In humor (and to restore equilibrium after the last quotation), Weller properly situates punctuated equilibrium between gradualism and true saltationism in his book Science Made Stupid (for another example, see Fig. 9-37).
These citations obviously vary greatly in cogency and utility, but they do indicate that punctuated equilibrium has struck a chord of consonance with themes in contemporary culture that many analysts view as central and troubling. Some usages amount to mere misguided metaphorical fluff, but others may direct and focus major critiques. In any case, since people are not stupid [Page 979] (at least not consistently so over such a broad range of disciplines), I must conclude that punctuated equilibrium has something general, perhaps even important, to say.
AN EPISODIC HISTORY OF PUNCTUATED EQUILIBRIUM
Early stages and future contexts
I have never enjoyed a reputation for modesty, so I believe that the following introductory comments represent a genuine memory, not a bias following a bent of personality. I was proud of our 1972 paper, and of my initiating oral presentation at the 1971 meeting of the Geological Society of America in Washington, D.C. I hoped that punctuated equilibrium would influence the practice of paleontology by showing that the fossil record, read literally, might depict the process of evolution as understood by neontologists, and not only reflect an absence of evidence pervasive and discouraging enough to make the empirical study of macroevolution virtually impossible at fine scale. Among the ordinary run of papers, this goal cannot be called modest, so I maintained some hope for punctuated equilibrium from the start. But I had no premonition about the hubbub that punctuated equilibrium would generate — for two reasons internal to the theory and to professional life, and also for our general inability to know the contingencies of external history.
For the internal reasons, I simply did not grasp, at first, the broader implications of punctuated equilibrium for evolutionary theory, as embodied in our proposals about stasis and the necessary explanation of macroevolutionary pattern by species sorting. I do clearly remember — and this recollection
9-37. A humorous perspective on punctuated equilibrium.
[Page 980]
continues to strike me as viscerally eerie — that I felt something significant lurking in the short section on trends (1972, pp. 111-112) that Eldredge had written. I somehow knew that this section included the most important claim in the paper, but I just couldn't articulate why. Second, I never imagined that the paper would generate any readership beyond the small profession of paleontology.
Two incidents reinforce my memory of modest expectations. My father, a brilliant and self-taught man who never had much opportunity for formal education and therefore grasped the logic of arguments far better than the sociological realities of the academy, got excited when he read the 1972 paper in manuscript, and said to me: “this is terrific; this will really make a splash; this will change things.” I replied with mild cynicism, and with the distinctive haughtiness of an “overwise” youngster who views his parents as naive, that such a hope could not be fulfilled because so few scientists ever bother to read papers carefully, or to mull over the implications of an argument not rooted exclusively in graphs and tables. As a second example, my former thesis advisor John Imbrie stopped to congratulate me on my “well argued non-Neo-Darwinian argument about paleontology and evolution” after my original oral presentation in 1971.1 appreciated the praise, but remained mystified by why he thought that an argument for operational paleobiology, based on proper scaling of allopatric speciation, could be viewed as theoretically iconoclastic as well.
The early history of punctuated equilibrium unfolded in a fairly conventional manner for ideas that “catch on” within a field. The debate remained pretty much restricted to paleontology (and largely pursued in the new journal founded by the Paleontological Society to publish research in the growing field of evolutionary studies — Paleobiology). Theoretical implications received an airing, but most discussion, to our pride and delight, arose from empirical and quantitative studies done explicitly to test the rival claims of gradualism vs. punctuation and stasis in data-rich fossil sequences. Most important were the critical studies of Gingerich (1974,1976) on putative gradualism in Tertiary mammalian sequences from the western United States. In any case, our hopes for a fruitful unleashing of empirical studies based on new respect for the power and adequacy of the fossil record were surely fulfilled.
Enough data, argument, and misconception as well had accumulated by the summer of 1976 that Eldredge and I decided to write a retrospective and follow-up — a longer article dedicated mostly to the detailed analysis of published data,
and appearing in Paleobiology under the title: “Punctuated equilibria: the tempo and mode of evolution reconsidered” (Gould and Eldredge, 1977). Meanwhile, we couldn't fail to note that the arguments of punctuated equilibrium, substantially aided by the support and extension of our colleague S. M. Stanley in a widely discussed PNAS article of 1975 that introduced the term “species selection” in a modern context (and developed the implications that I had been unable to articulate from our original section on evolutionary trends), were now beginning to attract attention in the larger [Page 981] field of neontological evolutionary studies. Stanley then followed with an important book on macroevolution (1979).
From an isolated South Africa, Elisabeth Vrba published an astonishing paper (1980) that gave an even more cogent and comprehensive voice to the macroevolutionary implications of punctuated equilibrium. (Following British custom from a former colony, she published as E. S. Vrba; Eldredge and I had never heard of her work and didn't even know her gender. The paper burst upon us as a most wonderful surprise.) In 1980, to fulfill an invitation from the editors to celebrate the 5th anniversary of our new journal Paleobiology, I then published a general article on the potential reform of evolutionary theory, a pretty modest proposal I thought, but, oh my, did neo-Darwinian hackles rise (see pp. 1002–1004).
At this point, the story becomes more like ordinary history in the crucial sense that predictable components, driven by the internal logic of a system, interact with peculiar contingencies to yield a result that no one could have anticipated. Punctuated equilibrium did begin to receive general commentary in professional journals (with Ridley's 1980 News and Views piece for Nature as a first example), but I am sure that our theory would never have become such a public spectacle if this interest had not coincided with two other events (or rather one event and a surrounding political context).
In October 1980, Chicago's Field Museum of Natural History held a large international conference on Macroevolution. This meeting, inspired in good part (but by no means entirely, or even mainly) by the developing debate over punctuated equilibrium, would have been a major event in our profession in any case. But the Chicago meeting escalated to become something of a cultural cause celebre because, and quite coincidentally, the symposium occurred at the height of renewed political influence for the creationist movement in America.
This fundamentalist movement, dedicated (as a major political goal) to suppressing the teaching of evolution in America's public schools, had flourished in the early 1920's under the leadership of William Jennings Bryan, had culminated in the famous Scopes trial in Tennessee in 1925, but had then petered out and become relatively inactive, especially following the 1968 Supreme Court decision, Epperson vs. Arkansas, that finally overturned the anti-evolution laws of the Scopes era on First Amendment grounds.
But creationism surged again in the 1970's, largely in response to an increasingly conservative political climate, and to the growing political savvy and organizational skills of the evangelical right. Creationists enjoyed a second round of success in the late 1970's, culminating in the passage of “equal time” laws for creationism and evolution in the states of Arkansas and Louisiana. We would eventually win this battle, first by overturning the Arkansas law in early 1982 (see pp. 986–990 for the role of punctuated equilibrium in this trial), and then by securing a resounding Supreme Court victory in 1987 in Edwards vs. Aguillard. But, in 1980 as the Chicago meeting unfolded, creationists were enjoying the height of their renewed political influence, and evolutionists were both justly furious and rightly worried. [Page 982]
Even with this temporal conjunction, the Chicago meeting wouldn't have attracted public attention if the press had not been alerted by accidental circumstances (neither the participants nor the organizers invited general journalists to the meeting). At most, reports would have appeared in the News and Views sections of Nature and Science, and professional history might have been tweaked or even altered a bit.
But the general press caught on and grossly misread the forthcoming meeting as a sign of deep trouble in the evolutionary sciences (rather than the fruitful product of a time of unusual interest and theoretical reassessment for a factual basis that no one doubted), and therefore as an indication that creationism might actually represent a genuine alternative, or at least a position that stood to benefit from any perceived confusion among evolutionists.
No single source can be blamed for thus alerting and misinforming the press, but an unfortunate article by James Gorman appeared in the popular magazine Discover just a month before the meeting (“The tortoise or the hare,” October, 1980), leading with the following confused and unfortunate paragraph:
Charles Darwin's brilliant theory of evolution, published in 1859, had a stunning impact on scientific and religious thought and forever changed man's perception of himself. Now that hallowed theory is not only under attack by fundamentalist Christians, but is also being questioned by reputable scientists. Among paleontologists, scientists who study the fossil record, there is growing dissent from the prevailing view of Darwinism. Partly as a result of the disagreement among scientists, the fundamentalists are successfully reintroducing creationism into textbooks and schoolrooms across the U.S. In October, a hundred or so scientists from half a dozen different disciplines will gather at Chicago's Field Museum...
This misconstruction yielded two unfortunate consequences — first, in inspiring a substantial contingent of the general press to attend the Chicago meeting under the false assumption that these technical proceedings would yield newsworthy stories about the success and status of creationism; and, second, by creating a blatantly false taxonomy that dichotomized natural historians into two categories: true-blue Darwinians vs. anyone with any desire to revise anything about pure Darwinism (including the strangest bedfellows of evolutionary revisionists and creationist ignoramuses). We must never doubt the potency of such false taxonomies, especially when promulgated by a general press that grasps the true issues poorly, and also plays to an audience too prone to read any dispute as a dichotomous pairing of good and evil. (Consider, for example, the harm done when scientific fraud, the worst of conscious betrayals for all we hold dear as a profession, gets linked with scientific error, a correctable and unavoidable consequence of any boldness in inquiry, because both lead to false conclusions. The pairing of punctuated [Page 983] equilibrium and creationism because both deny pure Darwinian gradualism, falls into the same category.)
The Chicago meeting also produced many good and responsible commentaries in the general press (Rensberger in the New York Times, November 4, 1980, for example) and in professional journals (Lewin in Science for November 21, 1980, for example). But some very bad accounts also appeared, especially unfortunate in their linkage of success for punctuated equilibrium with the spread of creationism. For example, a lead article in Newsweek (November 2, 1980), perhaps the most widely read of all reports, did properly brand the link as a confusion, and also stated that punctuated equilibrium represents a revision, not a refutation, of evolution, but such passing “subtleties” can easily be missed when subjects become so tightly juxtaposed, as in the Newsweek story: “At a conference in mid-October at Chicago's Field Museum of Natural History, the majority of 160 of the world's top paleontologists, anatomists, evolutionary geneticists and developmental biologists supported some form of this theory of 'punctuated equilibria.' While the scientists have been refining the theory of evolution in the past decade, some nonscientists have been spreading anew the gospel of creationism.”
This kind of reporting kindled the understandable wrath of orthodox Darwinians and champions of the Modern Synthesis. They became justifiably infuriated by two outrageous claims, both falsely linked to punctuated equilibrium by some press reports. First, some absurdly hyped popular accounts simply proclaimed the death of Darwinism (with punctuated equilibrium as the primary assassin), rather than reporting the more accurate but less arrest
ing news about extensions and partial revisions. For example, the same Newsweek article stated that “some scientists are still fighting a rear-guard action on behalf of Darwinism,” and “it is no wonder that scientists part reluctantly with Darwin.” Moreover, even the best and most balanced articles often carry exaggerated and distorted headlines (most scientists, I suspect, don't know that reporters are not generally permitted to write their own headlines). Boyce Rensberger's New York Times story on the Chicago conference could not have been more fair or accurate, but the hyped headline proclaimed: “Recent studies spark revolution in interpretation of evolution.” Since the article focussed on punctuated equilibrium, some colleagues then blamed Eldredge and me for an exaggeration promulgated neither by ourselves nor by the reporter.
Second, since punctuated equilibrium had served as the most general and accessible topic among the many questions debated at the Chicago Macroevolution meeting, our theory became the public symbol and stalking horse for all debate within evolutionary theory. Moreover, since popular impression now falsely linked the supposed “trouble” within evolutionary theory to the rise of creationism, some intemperate colleagues began to blame Eldredge and me for the growing strength of creationism! Thus, we stood falsely accused by some colleagues both for dishonestly exaggerating our theory to proclaim the death of Darwin (presumably in our own cynical quest for [Page 984] fame), and for unwittingly fostering the scourge of creationism as well. I believe that the strong feelings generated by punctuated equilibrium ever since cannot be divorced from this unfortunate historical context. (I also believe, of course, that the intense interest — as opposed to those intense feelings — arises largely from the challenging intellectual content of the theory itself.)
The Structure of Evolutionary Theory Page 156