Of course we made mistakes — serious ones in at least two cases — and the theory has changed and improved by correcting these errors. In particular, and as documented extensively in Chapter 8, we were terribly muddled for several years about the proper way to treat, and even to define, selection at the level of species — the most important of all theoretical spinoffs from punctuated equilibrium. We confused sorting with selection (see Vrba and Gould, 1986, for a resolution). We also did not properly formulate the concept of emergence at first; and we remained confused for a long time about emergence of characters vs. emergence of fitness as criteria for species selection (Lloyd and Gould, 1993; Gould and Lloyd, 1999). In retrospect, I am chagrined by the long duration of our confusion, and its expression in many of our papers. But I think that we have now resolved these difficult issues.
Secondly, as discussed on pages 796–798, I think that we originally proposed an incorrect reason for the association of rapid change with speciation. But I believe that we portrayed the phenomenology correctly, and that we have, with the help of Futuyma's (1987) suggestions, now developed a proper explanation. Thus, the theory of punctuated equilibrium has altered substantially to correct these two errors. Interestingly (and ironically), however, these important changes do not figure at all in the deprecating claims of the urban legend about our supposed retreats and chameleon-like redefinitions — for our detractors hardly recognize the existence of punctuated equilibrium's truly radical claim for evolutionary theory: its implications for selection above the species level, and for the explanation of trends.
Punctuated equilibrium, in short, has enjoyed true Darwinian success through the years: it has struggled, survived, changed and expanded. But the theoretical evolution of punctuated equilibrium belongs to the sphere of cultural change with its Lamarckian mode of transmission by direct passage of acquired improvements. Thus, the theory need not remain in Darwinian stasis, but may grow — as it has — in (gulp!) a gradualist and progressive manner.
The saltationist canard has persisted as our incubus. The charge could never be supported by proper documentation, for we never made the link or [Page 1009] claim. All attempts collapse upon close examination. Dennett, for example, who insists (1997, p. 64) that “for a while he [Gould] had presented punctuated equilibrium as a revolutionary 'saltationist' alternative to standard neo-Darwinism,” documents his supposed best case by assuring readers (1995, p. 285) that “for a while, Gould was proposing that the first step in the establishment of any new species was a doozy — a non-Darwinian saltation.” Dennett directly follows this claim with his putative proof, yet another quotation from my 1980 paper, which he renders as follows: “Speciation is not always an extension of gradual, adaptive allelic substitution to greater effect, but may represent, as Goldschmidt argued, a different style of genetic change — rapid reorganization of the genome, perhaps non-adaptive” (Gould, 1980b, p. 119).
I regard Dennett's case as pitiful, but the urban legend can offer no better. First of all, this quotation doesn't even refer to punctuated equilibrium, but comes from a section of my 1980 paper on the microevolutionary mechanics of speciation. Secondly, Dennett obviously misreads my statement in a backwards manner. I am trying to carve out a small theoretical space for a style of microevolutionary rapidity at low relative frequency — as clearly stated in my phrase “not always an extension of gradual...” But Dennett states that I am proposing this mechanism as a general replacement for gradual microevolutionary change in all cases of speciation — “the first step in the establishment of any new species” in his words. But my chosen phrase — “not always” — clearly means “most of the time,” and cannot be read as “never.” In short, I made a plea for pluralism, and Dennett charges me with usurpation. Then, when I try to explain, I am accused of beating a retreat to save face. When placed in such a double bind, one can only smile and remember Schiller's famous dictum: Mit Dummheit kdmpfen die Gotter selbst vergebens.
Finally, the claim that we equated punctuated equilibrium with saltation makes no sense within the logical structure of our theory — so, unless we are fools, how could we ever have asserted such a proposition? Our theory holds, as a defining statement, that ordinary allopatric speciation, unfolding gradually at microevolutionary scales, translates to punctuation in geological time. Microevolutionary saltation also scales as punctuation — so the distinction between saltation and standard allopatry becomes irrelevant for punctuated equilibrium, since both yield the same favored result!
Moreover, the chronology of debate proves that we did not issue disclaimers on this subject only to cover our asses as we retreated from exaggerations of our supposed second phase, because we have been asserting this clarification from the very beginning — that is, from the first paper we ever wrote to comment upon published reactions to punctuated equilibrium. Our first response appeared in 1977, long before we issued the supposed clarion call of our false revolution in 1980. We wrote (Gould and Eldredge, 1977, p. 121), under the heading “Invalid claims of gradualism made at the wrong scale”: “The model of punctuated equilibria does not maintain that nothing occurs gradually at any level of evolution. It is a theory about speciation and its deployment in the fossil record. It claims that an important pattern, continuous [Page 1010] at higher levels — the 'classic' macroevolutionary trend — is a consequence of punctuation in the evolution of species. It does not deny that allopatric speciation occurs gradually in ecological time (though it might not — see Carson, 1975), but only asserts that this scale is a geological microsecond.”
We have never changed this conviction, and we have always tried to correct any confusion of scaling between saltation and punctuation, even in papers written during the supposed apogee of our revolutionary ardor, during illusory stage 2 of the urban legend. For example, under the heading of “The relationship of punctuated equilibrium to macromutation,” I wrote in 1982c (p. 88): “Punctuated equilibrium is not a theory of macromutation ... it is not a theory of any genetic process ... It is a theory about larger-scale patterns — the geometry of speciation in geological time. As with ecologically rapid modes of speciation, punctuated equilibrium welcomes macromutation as a source for the initiation of species: the faster the better. But punctuated equilibrium clearly does not require or imply macromutation, since it was formulated as the expected geological consequence of Mayrian allopatry.”
An interlude on sources of error
With such limited skills in sociology and psychology, and from too close a personal and partisan standpoint, I cannot claim much insight into the general sources of persistent nonscientific errors among professional colleagues. But I wish to offer a few thoughts, at least to separate what Eldredge and I must own from the truly unfair, and often intemperate, charges so often made against us.
Any complex situation arises from multiple causes, with inevitable shortcomings on both sides of any basically dichotomous issue. But when I list our own faults and failures, I find nothing of great depth, and no indication of any sustained stupidity, carelessness, lack of clarity, or malfeasance. Thus, I continue to feel far more aggrieved than intemperate — although I wouldn't give up this lifetime's intellectual adventure for any alternative construction of a scientific career.
For our part, I think that critics can identify three sources of potential confusion that might legitimately be laid at our doorstep, and might have been prevented had our crystal ball been clearer.
1. In our original paper (Eldredge and Gould, 1972), but not subsequently, we failed to explain, in a sufficiently didactic and explicit manner, that when paleontologists use such terms as “rapid,” “sudden,” or “instantaneous,” they refer to expressions of events at geological scales, and not to rates of change in microevolutionary time. But we cannot be blamed for anything more than a failure to anticipate the range of interest that our paper would generate. After all, we wrote this paper for paleontologists, and never expected a wider au
dience. We used the standard terminology of our profession, well known and understood by all members of the clan. Indeed, few non-paleontologists ever read this original article, published in an obscure symposium volume with a small press run. From 1977 on, in all papers widely read [Page 1011] by neontologists, and serving as a basis for enlarged discussion, we clearly explained the differences in scaling between micro- and macroevolutionary rates.
2. As acknowledged on pages 1002–1004, I did use some prose flourishes that, in a context of considerable suspicion and growing jealousy, probably fanned the flames of confusion. Although I never stated anything unclearly, and committed no logical errors that could legitimately have inspired a resulting misreading, I should have toned down my style in a few crucial places.
3. We may have sown some confusion by using partially overlapping terminology for a specific theory (punctuated equilibrium), and for the larger generality (punctuational styles of change) in which that theory lies embedded. But this taxonomic usage does stress a legitimate commonality that we wished to emphasize. We also chose and used our terms with explicit consistency and clear definitions — so careful reading should have precluded any misunderstanding.
The testing and development of punctuated equilibrium — a well defined and circumscribed theory about the origin and deployment of speciation events in geological time — has always been our major concern. But as students of evolution, we have also been interested in the range of applicability for the geometric generalization represented by this theory — the unfolding of change as occasional punctuation within prevailing stasis, rather than as gradualistic continuity — to other scales of space and time, and for other causes and phenomena of life's history. We have called this more general and abstract style of change “punctuational,” and have referred to the hypothesis favoring its generality as “punctuationalism.”
We have always been careful and clear about the differences between our specific theory of punctuated equilibrium and the general proposition of punctuational change. (In fact, we strove to be explicit, even didactic, about this distinction because we recognized the confusion that might arise otherwise.) But perhaps the words are too close to expect general understanding of the distinction, particularly from hostile critics who have invested their emotional ire in the legend that we have been pursuing an imperialistic, grandstanding quest to enshrine punctuated equilibrium as a new paradigm for all the evolutionary sciences.
Still, as a statement of a basic intellectual principle, why should we allow ourselves to be forced into suboptimal decisions by the least thoughtful and most emotionally driven forms of misunderstanding among critics? Punctuationalism is the right and best word for the general style of change expressed by punctuated equilibrium as a specific example at a circumscribed level and phenomenology. As long as we take special care to be clear and explicit about the distinction, why should we sacrifice this most appropriate form of naming? I believe that we have been scrupulous in characterizing and highlighting this point, right from our first introduction in 1977, when we began a section entitled “Towards a general philosophy of change” with these words: “Punctuated equilibria is a model for discontinuous tempos of change at one biological level only: the process of speciation and the deployment of species in [Page 1012] geological time. Nonetheless, we believe that a general theory of punctuational change is broadly, though by no means exclusively, valid throughout biology” (Gould and Eldredge, 1977, p. 145). In 1982, in the midst of illusory stage 2, when I was supposedly touting macromutation as the cause of punctuated equilibrium in order to dethrone Darwinism, I explicitly drew the same distinction in order to separate the phenomena, while noting an interesting similarity in abstract geometric style of change across scales (Gould, 1982c, p. 90):
These legitimate styles of macromutation are related to punctuated equilibrium only insofar as both represent different and unconnected examples of a general style of thinking that I have called punctuational (as opposed to gradualist or continuationist thought). I take it that no one would deny the constraining impact of gradualistic biases upon evolutionary theorizing. Punctuational thinking focusses upon the stability of structure, the difficulty of its transformation, and the idea of change as a transition between stable states. Evolutionists are now discussing punctuational theories at several levels: for morphological shifts (legitimate macromutation), speciation (various theories for rapid attainment of reproductive isolation), and general morphological pattern in geological time (punctuated equilibrium). These are not logically interrelated, but manifestations of a style of thought that I regard as promising and, at least, expansive in its challenge to conventional ideas. Any manifestation may be true or false, or of high or low relative frequency, without affecting the prospects of any other. I do commend the general style of thought (now becoming popular in other disciplines as well) as a fruitful source for hypotheses.
However, when I turn to factors that must be laid at our critics' doorstep, I can compile a longer and more serious list, including attitudes and practices that do compromise the ideals of scholarship. (Remember that I deal, in this section, only with personal and nonscientific critiques of punctuated equilibrium. We have also been properly subjected to very sharp, entirely appropriate, and fully welcomed criticism of a technical and scientific nature — and the theory of punctuated equilibrium has only been altered and improved thereby. I have discussed these legitimate criticisms in Section IV of this chapter.)
1. The emotional source of jealousy. Given the vehemence of many deprecations, combined with a weakness or absence of logical or scientific content, I must conclude that the primary motivating factor lies in simple jealousy — that most distressing, yet most quintessentially human, of all destructive emotions (“as cruel as the grave” according to the Song of Songs; “the jaundice of the soul,” in Dryden's metaphor; and, in the most memorable definition of all, Shakespeare's words of warning to Othello: “It is the green-eyed monster which doth mock the meat it feeds on”).
Punctuated equilibrium has generated a large and public volume of commentary. I am confident that genuine interest and content has generated the [Page 1013] bulk of this publicity, but I understand the all too human tendency to view achievements of perceived rivals as imposture rooted in base motivation. Moreover, jealousy gains a particularly potent expression in science for the ironic reason that professional norms do not permit us to acknowledge such feelings or motivations, even to ourselves. Our negativities are supposed to arise from perceived fallacies in the logic or empirical content of hypotheses we dislike, not from personal expressions of envy. Thus, if our emotions exude distress and anger, but we cannot admit, or even recognize, jealousy as a source, then we must impute our genuine envy to the supposed intellectual malfeasance of our opponents — and our internal feeling becomes falsely objectified as their failing. This form of transference leads to larger problems in the sociology of science than we have generally been willing to admit.
2. THE PHILOSOPHICALLY INTERESTING ISSUE OF LIMITED CONCEPTUAL space. I have long faced a paradox in trying to understand why many intelligent critics seem unable to understand or acknowledge our reiterated insistence that the radical claim of punctuated equilibrium lies not in any proposal for revised microevolutionary mechanisms (especially not in any novel explanations for punctuations), but rather at the level of macroevolution, in claims for efficacy of higher-level selection based on the status of species, under punctuated equilibrium, as genuine Darwinian individuals.
When smart people don't “get it,” one must conclude that the argument lies outside whatever “conceptual space” they maintain for assessing novel ideas in a given area. Many evolutionists, particularly those committed to the strict Darwinism of unifocal causation at Darwin's own organismic level, or below at the genic level, have never considered the hierarchical model, and apparently maintain no conceptual space for the notion of effective selection at hig
her levels. These scientists then face the following situation: (1) they note correctly that punctuated equilibrium stakes some claim for novelty within evolutionary theory; (2) their concept of “evolutionary theory” does not extend to causation above the organismic level, so they do not grasp the actual content of our claim; (3) they correctly understand that punctuated equilibrium offers no radical statement about microevolutionary mechanics; (4) Q.E.D., the authors of punctuated equilibrium must be grandstanding by asserting a radical claim without content. But the limit lies within the conceptual space of our critics, not in the character of our rhetoric.
3. THE PARTICULAR PREJUDICE THAT FANS THE FLAMES. Certain Words embody unusual power, for reasons both practical and emotional — “fire” in a crowded theater, or “communist” at right-wing pep rallies of old. For reasons of impeccable historical pedigree, thoroughly explored in Chapters 2–6 of this book, and rooted largely in Darwin's own philosophical preferences, the most incendiary words for dedicated Darwinians (once we get past Lamarckism, creationism, and a few others) must be the various synonyms of “sudden” — “rapid,” “instantaneous,” “quick,” “discontinuous,” and the like. Proponents of punctuated equilibrium do use these words — but at an appropriate scale of geological time, to express microevolutionary continuities that translate to punctuations in this larger temporal realm. Nonetheless, [Page 1014] some orthodox Darwinians react with knee-jerk negativity towards any claim at all about rapidity. Any invocation of “rapid” must conjure up saltation and Goldschmidt, and must be met by counterattack. How else can we explain such a persistent confusion based on a false construction, then elevated to an urban legend, that the originators of punctuated equilibrium have always tried to identify and dispel?
The Structure of Evolutionary Theory Page 161
