Scientific and Technical Communication: Theory, Practice and Policy | Migrating Across Disciplinary Boundaries: The Case of David Raup's and John Sepkoski's Periodicity Papers

Introduction

Historically, calls for interdisciplinarity have come either from disciplinarians hoping to invigorate their disciplines or from scholars who encounter a problem that transcends disciplinary lines. The first group are often specialists working within an emerging field in search of legitimacy or specialists within a discipline which has become stagnant and inbred. For instance, when the field of speech communication was in its infancy, Charles Woolbert argued that the emerging field shared territory with such established fields as English, history, law, political science, sociology, education, and philosophy (Woolbert, 1916: 72). Similarly Maxine Hairston, during a crucial time in the emerging discipline of composition studies, called for interdisciplinary ties: "[W]e have to extend our connections to disciplines outside our field--not only to linguistics, philosophy, cognitive psychology, and speech communication, but to less obviously connected fields such as biology, economics, and even the arts" (Hairston,1985: 279-280). Conversely, specialists within stagnant disciplines also call for interdisciplinarity. Barbara Herrnstein Smith acknowledges that dissatisfaction with traditional definitions of, and methodologies in, literary studies has opened the borders of the domain to traffic from other disciplines (Smith, 1989: 2). Even Stanley Fish, who claims that a scholar can inhabit only one disciplinary mindset at a time, rejoices in the positive effects interdisciplinarity has had on literary studies (Fish, 1989: 20-21).

Whether such calls come from juvenile or geriatric disciplines, they focus on the needs of the discipline. However, the other kind of call for interdisciplinarity focuses, not on the needs on the discipline, but on the need to fully understand a subject which does not fit nicely into disciplinary categories. Cifford Geertz's "Blurred Genres" signals an awareness that the disciplinary boundaries established in the last century are undergoing a reconfiguration. He claims that interdisciplinarity results from the recognition "that the lines grouping scholars together into intellectual communities . . . are these days running at some highly eccentric angles" (Geertz, 1980: 169). Wayne Booth, pointing out that several disciplinary attempts to explain why people change their minds have been limited by their narrowness, advocates a pluralistic approach when he says rhetoricians must "repudiate once and for all the notion of a takeover and embrace rather the notion of a pluralistic set of arts, learning from all relevant disciplines and indeed willing to be absorbed by other disciplines at appropriate moments" (Booth, 1971: 106).

Although Booth sounds as though he has little concern with disciplinary boundaries, at the heart of pluralism is a regard for the domains of disciplinary knowledge. Thus, collaboration is a project that entails reinterpretation without transformation. Stanley Fish's claim that importations from outside disciplines must be translated into the language of one's disciplinary home (Fish, 1989: 19) is consistent with Booth's pluralist approach. Conversely, Arabella Lyon argues that if interdisciplinary projects are to succeed, they "require more than simple importation of texts; the disciplines involved apparently need to share aims and actions (methodologies) if the imported texts are to blend and be productive" (Lyon, 1992: 684).

Steve Fuller also rejects pluralistic notions of interdisciplinarity. Arguing that collaborative projects which "abide by the local standards of all the disciplines drawn upon" are hardly improvements over disciplinary studies, he accuses pluralists of falling into the "fallacy of eclecticism" (Fuller, 1993: 41-42). In place of pluralistic conceptions of interdisciplinarity, Fuller puts forward a theory of interdisciplinarity as interpenetration, "an instance of strategically suppressed disagreement that enables an audience to move temporarily in a common direction" (35).

The two views of interdisciplinarity presented above have been labeled interdisciplinary and integrative approaches respectively (Klein, 1990: 27). Pluralist, or interdisciplinary, approaches follow the metaphor of "bridge building," whereas interpentrative, or integrative, approaches follow the metaphor of "restructuring" (27). These two approaches are really two extremes along a continuous spectrum, for even the most radical interpentrative collaboration will involve people whose experiences and perspectives are informed by their disciplinary training; conversely, it is impossible for specialists from different areas to engage in meaningful ways without some restructuring of knowledge and method. As Julie Klein says, "[Interdisciplinarity] is a process for achieving an integrative synthesis" (188).

Although some theorists favor one approach over another for ideological reasons, both types of collaboration exist and rhetorical studies of both are beginning to appear. For instance, Kaufer and Young, in their discussion of writing in the content areas, describe an instance in which restructuring of a biologist's and a rhetorician's definition of their own expertise took place. They end their article with an observation that captures the "restructuring" mindset: "Both must be willing to travel" (Kaufer and Young, 1993: 102). On the other hand, McCarthy and Fishman, in their "Boundary Conversations," describe a collaborative project that more closely resembles "bridge building": Disciplinary ways of knowing are not broken down but simply juxtaposed (McCarthy and Fishman, 1991: 434). Both of these studies reflect upon the experiences of the writers as participants in collaborative projects.

Rhetorical case studies of interdisciplinary discourse in which the scholar was not a participant are also beginning to appear. One of the earliest to my knowledge is a study of Niles Eldrege's and Stephen Jay Gould's difficulty in accommodating various disciplinary audiences as they presented their theory of punctuated equilibria (Lyne and Howe, 1986). This study brought to light the territorial squabbles that resulted from their making claims which transcended their home discipline. And Debra Journet (Journet, 1993) explores the rhetoric of S. E. Jelliffe who adopted the rhetorical strategy of mixing genres and thereby created an interdisciplinary audience for his theory of psychosomatic medicine. Despite these studies, the literature on interdisciplinary rhetoric is sparse, and few can argue with Klein's assertion that "We would know more about how individuals use these [interdisciplinary] skills if there were more accounts of how interdisciplinarians actually work" (Klein, 1990: 183).

A Case Study of Successful Interdisciplinary Rhetoric

In this chapter I analyze a successful example of interdisciplinary rhetoric, an article that was part of an ongoing scientific project attempting to explain the causes of mass extinctions. My purpose in analyzing this paper is to describe the authors' interdisciplinary rhetorical skills. Specifically, I show that the authors were successful in their interdisciplinary rhetoric because of their sense of timing (kairos) and their imaginative projection of an appropriate ethos.1

The paper which I analyze was written by David M. Raup and J. John Sepkoski, Jr. It is titled "Periodicity of extinctions in the geologic past," and it appeared in the Proceedings of the National Academy of Sciences, USA, (PNAS), 1984. To understand the context, we must turn the clock back. An article which appeared four years before Raup's and Sepkoski's created intense interest in mass extinctions. In June of 1980, Science published an article by Luis W. Alvarez, Walter Alvarez, Frank Asaro, and Helen V. Michel, titled, "Extraterrestrial Cause for Cretaceous-Tertiary Extinction." Reporting their discovery of unusually high concentrations of iridium in rock strata associated with Cretaceous-Tertiary extinctions, Alvarez, et. al., suggested that the iridium, which is largely of extraterrestrial origin, settled out of the atmosphere after a large meteorite hit the earth spewing tons of pulverized dust into the atmosphere, darkening the earth, cutting off photosynthesis and leading to mass extinctions (Alvarez, et.al, 1980: 1104). Not unlike the hypothesized meteorite, this article impacted the scientific community with such force that its fallout continues to show up in the journals over a decade after its publication. The Alvarez hypothesis initiated several years of collaborative efforts to ascertain whether or not meteorite impacts have caused mass extinctions.

Raup and Sepkoski contributed to this ongoing project, advancing the Alvarez hypothesis and making a controversial claim of their own. Specifically, they claimed that they had found statistical evidence in the geological record supporting a theory that mass extinctions have happened periodically on a 26-million-year (ma) cycle. The paper is an example of a particular kind of interdisciplinary rhetoric, one which respects expertise and boundaries and yet moves beyond those boundaries. If the success of a paper is judged by the interest and response it generates, then this paper is a very successful interdisciplinary article.

Raup and Sepkoski were not the first to put forward a theory that extinctions were cyclical. Alfred G. Fischer and Michael A. Arthur had published a paper in 1977 suggesting that extinctions occur on a 32-million-year cycle. Their idea had not caught on. Their suggestion, if true, would have been revolutionary, but as Raup says in The Nemesis Affair, "Many of us (most in fact) did our best to look the other way. Fischer and Arthur were claiming that the major extinctions of the past 250 million years were evenly spaced, coming every 32 million years. This was anathema!" (Raup, 1987: 107). Given the failure of Fischer and Arthur in 1977 and the success of Raup and Sepkoski in 1984, the question "why?" seems to demand an answer. One part of the answer is that the time was not ripe when Fischer and Arthur made their suggestion.

The Open Door: Kairos as Rhetorical Timeliness

The first rhetorical dynamic that contributed to Raup's and Sepkoski's successful interdisciplinarity was their sense of timing. In classical rhetoric, the Greek word kairos refers to a rhetorical situation that is ripe, an opportunity or window during which otherwise difficult or impossible tasks become possible. 2 When a rhetor grasps the kairos, her rhetoric is kairotic, or timely. Raup's and Sepkoski's paper was rushed into publication in order to take advantage of an open window. In The Nemesis Affair, Raup says, "We wanted quick publication, although there was no compelling reason for any hurry" (Raup, 1987: 127). He then explains that he and Sepkoski weren't worried about being scooped, but, he says, "[we] felt like we had something exciting and we were impatient to get it in print" (127). In 1984 (among scholars interested in the geological record and evolutionary change) being able to show statistical evidence to support periodicity of mass extinctions was similar to being able to unravel the structure of DNA in 1953.

The time (kairos) was ripe for this paper; many changes had occurred in the seven years since the appearance of the Fischer and Arthur paper; most notably the Alvarez paper about the iridium anomaly at the K-T boundary had appeared in 1980. After the Alvarez paper appeared, several interdisciplinary conferences were held in which the topic of mass extinctions and meteoric impacts had been discussed. Three of these conferences were the Snowbird conference in October 1981, the Dahlem conference in Berlin during May of 1983, and the "Dynamics of Extinction" symposium held in Flagstaff, Arizona, in August 1983 (Raup, 1987: 25). The first is significant because its main topic was the Alvarez hypothesis. At the second, David Raup presented, for the first time and in an informal way, his and Sepkoski's data about periodicity. At the third, Sepkoski presented the data formally. Roger Lewin, a professional science writer, reported on Sepkoski's presentation in the September 2, 1983, issue of Science, and so Raup and Sepkoski were in the situation of needing to publish their study rapidly because news of it was already out. In fact, because the Lewin article had mentioned a possible connection with extraterrestrial causes, certain astrophysicists were requesting preprints of the forthcoming article (Raup, 1987: 136).

Other changes had also taken place. Perhaps the most comical was that Alvarez had reported discovering another iridium anomaly in Montana in Science 1981, only to find out later that the iridium had not come from outer space, or even from Montana, but from the wedding band worn by the technician who prepared the samples for analysis. In his retraction, Alvarez gave errors of this kind a new name, "wedding-ring anomalies" (Alvarez, et. al., 1982: 888). However, while retracting his Montana claim, Alvarez reported finding another iridium anomaly, this time associated with the Eocene extinctions. Thus, evidence for meteoric impacts in coincidence with extinctions was mounting.

Furthermore, there were some new tools available. One was Sepkoski's Compendium of data on the fossil record of life, which had been put on computer disks enabling quick database searches and statistical analyses. Another important tool was W. B. Harland's A Geological Time Scale, 1982. According to the review of that book, the Harland time scale is a cutting edge and comprehensive synthesis of available data (Dalrymple, 1983: 944). The combination of a mood of expectation, a more useful compendium of the fossil record, and an updated and more authoritative geologic time scale set the stage for Raup's and Sepkoski's periodicity paper. Furthermore, the audience for extinction papers was larger than in 1977 because the Alvarez paper had been published in Science and had transcended disciplinary lines. This conversation was not representative of science as puzzle solving but science in the process of a paradigm shift (from Lyell's gradualism to the view that earth history has been shaped by catastrophes); it was a time of revolutionary science and rapid change.

Raup's and Sepkoski's sense of timeliness seems to permeate the text of the periodicity paper. In several places they refer to the moment or to the rapid process of change. In their purpose statement they say their purpose is to test Fischer's proposition by using "as rigorous methodology as present data permit" (Raup and Sepkoski, 1984: 801, italics added). They had the best data available at the time in Sepkoski's Compendium, but they knew it was changing. Sepkoski was busy trying to expand the data to accommodate analysis of records for levels more specific than that of the family. Explaining their decision to place extinctions at the ends of stages of geologic time, they say their inference is the best "in the present state of knowledge" (802). At another point, they wish to dismiss a possible 30-ma (million-year) periodicity, and so they say that it "cannot be confirmed with the present time scales" ((804). Qualifying their claim in the conclusions section, they explain that the length of the cycle may shift as time scale data improve (805, italics added). Furthermore, "at present" Sepkoski's data do not support one geologist's 50-ma hypothesis; in fact, "due to the relatively weak state of the Paleozoic time scale . . . nothing can be said unequivocally at this time" (805). Finally, they call for timely help from astrophysicists when they say, "much more information is need before definitive statements about causes can be made" (805, italics added).

The kairotic nature of the article is also reinforced by pronouncements about the importance of the work. They claim that their conclusion is "inescapable" (804), a word that creates the image of prey being cornered, ready to be snared. There is a sense of impending changes in science because, as they put it, "The implications of periodicity for evolutionary biology are profound" (805). Though they do not refer to Lyell or Cuvier, they and their readers know that Lyell's gradualism, which won the day over Cuvier's catastrophism in the early 1800s, was in danger of being overthrown, a possibility that caused even the authors some "philosophical anguish" (Lewin, 1983: 936). Thus, changes had been taking place and even greater changes were on the horizon; this paper inhabits an opportune moment, a rhetorical kairos. Unlike Fischer's and Arthur's paper that suggested a 32-ma periodicity and languished uncited in 1977, this paper virtually exploded on the scene. Remarkably, just two months after this paper was published, four papers suggesting astrophysical causes for periodicity and one paper showing periodicity in meteorite craters appeared in the April 19, 1984, issue of Nature. The first four articles, all by astrophysicists, cite the periodicity paper by Raup and Sepkoski as their first reference, and the fifth paper, by a geologist, cites it as the fifth reference. These papers, printed under the title "Letters to Nature," came in to Nature even before the periodicity paper appeared in publication. All of the authors were working from preprints, a situation which caused John Maddox, editor of Nature, to reprimand Raup and Sepkoski for their unorthodox behavior. He says, "The most obvious complaint against the system [of circulating preprints] is that it is discriminatory, excluding from the circle of those in the know people who happen not to be on the authors' mailing list" (Maddox, 1984: 685). There would have been no call for John Maddox's reprimand in times of normal science, but in that season of rapid change and kairotic opportunity, Maddox was forced to say something in order to protect a system that is supposed to give voice to science but which in extraordinary times is too slow to keep pace with the changes.

The Inviting Image: Ethos as Rhetorical Identification

The second factor that contributed to the successful interdisciplinary rhetoric of this article is the authors' projection of an appropriate ethos. In ancient Greek, the words to prepon meant "the appropriate"; in relationship to rhetoric, the appropriate changes with circumstances, and so rhetors must be able to adapt to the rhetorical situation.3 Ethos refers to the persona projected during a speech or contained within a paper. An appropriate ethos, therefore, is a manufactured image or persona that gains attention, elicits trust, and invites participation within a changing environment. In short, it is ethos that causes the audience to identify with the writer or speaker, and it is through identification that consubstantiality is formed, and it is through consubstantiality that people act together in collaborative endeavors (Burke, 1969: 21). Creating identification is difficult enough in disciplinary rhetoric; doing so in interdisciplinary situations is much more difficult.

Raup's and Sepkoski's periodicity article appeared in the Proceedings of the National Academy of Sciences (PNAS) in February 1984, just four months after it was submitted and just five months after Lewin's report on Sepkoski's presentation of the research had appeared in Science. PNAS is published by the National Academy, which is made up of some 1500 people considered to be top scholars in the sciences. The Academy was created by Congress to advise the government on scientific matters. Members of the Academy can publish in PNAS without going through peer review, and because David Raup was a member, the periodicity paper was published without being refereed. Although he claims that only a couple critics have chastised him and Sepkoski for not publishing in a refereed journal, Raup spends three pages in The Nemesis Affair (126-129) explaining their decision to do so. Compensating for its not being refereed, Raup points out that the journal has a quick publication schedule and a large circulation in the United States and abroad. Furthermore, it is a respected journal because it speaks for the Academy, a prestigious "club" that not even Carl Sagan is a member of (Raup, 1987: 164). Another advantage of publishing in PNAS, although Raup does not specifically mention it, is that it is an interdisciplinary journal. Scientists from several disciplines would read it; this is the kind of audience Raup and Sepkoski wanted because the controversy over extinctions was spilling over the boundaries of paleontology and geology into other fields.

The paper, framed by an abstract at the front and acknowledgements and references at the end, is divided into the following sections:

Introduction
Data Base
Measurement of Extinction Rates
Statistical Analysis of the Time Series
Fourier Analysis
Nonparametric Testing
Best-fit Cycle
Conclusions
Implications

To create identification in an interdisciplinary context, Raup and Sepkoski take on different personae as the paper develops and thereby move the audience from one room in the larger house of science to other rooms. In the introduction, data base, and measurement sections, they assume the personae of orthodox paleontologists. In the statistical analysis section, they assume the roles of expert statisticians. In the conclusions section they combine the two previous personae, and in the implications section they play the role of speculative generalists or amateur astrophysicists. These changing personae make up an appropriate interdisciplinary ethos which invites participation from diverse quarters.

In the introduction, they assume the roles of paleontologists instructing those outside that discipline. First, they make a bold declaration, "virtually all species of animals and plants that have ever lived are now extinct," a claim that may shock outsiders but is presented as a settled issue within the field. They then instruct the reader about the basic assumptions of the field, namely that the extinction process is usually considered a continuous process. Among the articles cited to demonstrate this traditional, orthodox assumption is Raup's own article on cohort analysis, which appeared a couple years before the Alvarez paper and can be described as containing a conservative view of extinctions. By placing that article among the traditionalists' articles, Raup and Sepkoski signal their own conservatism. They then inform those outside the field, though most are aware, that there is "increasing evidence" that extinctions are short-lived events, and they cite the Fischer and Arthur 1977 paper which Raup had originally considered anathema. What was unspeakable seven years earlier has now found its way into the introductory paragraph of a major paper, but not without qualification. After explaining that Fischer and Arthur used a limited data base and did no statistical testing, Raup and Sepkoski announce their purpose: "The purpose of this paper, therefore, is to test the proposition of periodicity in the record of marine extinctions over the past 250 ma (Late Permian to Recent) by using as rigorous a methodology as present data permit" (801). Having opened the possibility of talking about periodicity by citing the Fischer and Arthur study and having shown the deficiencies of that study, Raup and Sepkoski have opened space for their own news. Surprisingly, the 1980 Alvarez paper has not been cited at this point in the paper, and it isn't cited until the implications section of the paper.

In the next two sections (data base and measurement of extinction rates) Raup and Sepkoski maintain the ethos of conservative paleontologists with progressive methodologies and state-of-the-art material, discussing their improved data base, namely the Sepkoski compendium and the Harland time scale. They still sound like paleontologists, however, because the issues addressed are field specific--the arbitrariness of the definition of "family" (Lewin had called it a mysterious unit in his article) and the discrepancies between the Harland scale and the Odin scale. Furthermore, the discussion of how to measure extinction rates, though sophisticated, is an in-house sort of topic, a subject best left to paleontologists.

However, in the statistical analysis section of the paper, a section that is really the heart of the paper, they assume the role of expert statisticians.4 This change in persona is signalled when they say, ". . . qualitative impressions may be misleading. For this reason, we have applied a variety of standard and nonstandard tests of periodicity to the time series" (802). It's as though they come out of the provincial quarter of paleontology with its "nineteenth-century" flavor into the cosmopolitan world of the academy forsaking the vernacular and adopting the lingua franca of statistics.5

Raup and Sepkoski act as though they are among peers when they talk statistics. They use technical language usually without defining it: "smooth power spectrum," "first harmonic," "random walk," "composite cycle," and "non-unimodal curve." They carefully explain the statistical procedure they followed to get their results, displaying concern that other statisticians will be able to judge the validity of their procedure. Not only do they discuss their Fourier analysis and their best-fit analysis, they also divide the nonparametric test procedure into three subparts, explaining how they placed several periodic impulse functions on the time series, randomized the real data, and compared the standard deviations of the real data with a distribution formed by 500 simulations (802).

They address issues tied primarily to statistics rather than to paleontology. For example they say, "It can be argued that the necessary minimal spacing of 12 X 106 years between observed extinction peaks can make random (Poisson) data appear periodic to Fourier analysis" (802), and "It could be argued that the statistical significance of the results could have been generated by periodic elements in the scale itself" (803). They report their results in terms of levels of statistical significance, showing that their tests give results well within P<0.01 for their claimed 26 ma (million year) periodicity (803). Reporting three major statistical tests and seemingly innumerable variations of those tests, Raup and Sepkoski project an image of expert statisticians: they are knowledgeable about programming computers, about statistical procedures, about possible sources of error, and about levels of significance.

Having established their ethos first as paleontologists (conservative in theory, progressive in methods) and second as statisticians, Raup and Sepkoski have made room for their major claim, which appears in the conclusions section of the paper: "It seems inescapable that the post-Late Permian extinction record contains a 26-ma periodicity, assuming that the Harland time scale . . . is a reasonable approximation of reality" (804-805). In this short section of the paper, the two previous roles--paleontologist and statistician--are combined. They once again talk like paleontologists, referring to the "Permian-Miocene interval" and the "Early Triassic" (804); but they also continue to use terms like "autocorrelation" and "nonparametric test" (805). They report one last test in this section, one in which they had attempted to find out if the 26-ma periodicity was some kind of statistical shadow of a 52-ma cycle. They claim that their tests do not support the latter. This seeming excursion from the direct path makes little sense unless we have read Lewin's report of the Flagstaff conference. There we find out that Eugene Shoemaker--an expert in meteorite craters--had said that we could "expect to incur a significant [meteor] impact on a 50-million year cycle" (Lewin, 1983: 936). Without specifying the significance of their test, Raup and Sepkoski have set up the final section of the paper, headed "Implications."

As they have migrated through different personae, Raup and Sepkoski have managed to bring paleontologists and statisticians together in one audience. Their last report in the conclusions added geologists to the train, but in this final section of the paper, they anticipate others as well, specifically astrophysicists. They are moving from what Raup calls his "corner of science" (Raup, 1987: 150) to the common parlor, claiming that if periodicity can be demonstrated, "implications are broad and fundamental" (805).

In order to accommodate the astrophysicists, Raup and Sepkoski take on the personae of generalists and of amateur astrophysicists. First, as generalists, they adopt a form of deductive reasoning easily followed by non-specialists. Their reasoning is in the form of a descending logic tree made up of an "if" clause followed by a question which provides a set of alternatives. The second alternative is always the logical choice. For example, after questioning whether the causes (forcing agent) of this apparent periodicity are biological or environmental, they then say, "If the forcing agent is in the physical environment, does this reflect an earthbound process or something in space?" (105). Thus, by gradual removes down the logic tree, they migrate from the ethos of their own expertise to the field of astrophysics, speculating that perhaps the cause is the solar system's passage through the spiral arms of the galaxy, which would, "increase the comet flux" (805). Not until this point, some twenty lines from the end of the article, do they reference the Alvarez paper of 1980 which initiated the conversation they are participating in. They simply mention that their scenario would follow the "Alvarez hypothesis." In this final section of the paper they reference Shoemaker, Alvarez, and Ganapathy, all geologists who can contribute information about meteorite craters and iridium anomalies, but they can not speak authoritatively about larger issues in astronomy. They leave the door open for experts in astrophysics, saying, "However, much more information is needed before definitive statements about causes can be made" (805).

Conclusions

As I think the above analysis demonstrates, the interdisciplinary rhetoric of Raup and Sepkoski migrates across boundaries. Raup and Sepkoski seem to be cosmopolitan travelers capable of speaking the local dialect of paleontology but also the lingua franca of statistics, able to engage in esoteric methodologies of experts and in the well-worn but reliable methodology of descending logic trees. They are able to become "all things to all people."

Such rhetoric can happen only in special circumstances, when the timing is right. And even then, there is no guarantee of success. Through their skillful manipulation of personae, Raup and Sepkoski create an environment in which identification, consubstantiality, and collaborative work may occur. They build bridges between disciplines and respect disciplinary boundaries while they simultaneously restructure the relationship between the disciplines, getting diverse people to move at least temporarily in the same direction, and adding to a growing body of knowledge within the interdisciplinary project of understanding the history of mass extinctions.

Notes

(Bottom of first page.) This article originally appeared in Social Epistemology (Taylor and Francis, ISSN 0269-1728), Volume 9, Number 2, April-June 1995. Reprinted here with the publisher's permission.

1 Most discussions of ethos rely heavily on Aristotle's discussion of it as one of the three pisteis, along with logos and pathos. The literature on ethos is extensive. (See, for example, Halloran, 1982; Miller's and Halloran, 1993; Corts, 1968; Arthur Miller, 1975; Sattler, 1947; Sullivan, 1993.)

2 There are several articles which discuss kairos as it pertains to rhetoric (Poulakos, 1983; Kinneavy, 1986; Carter, 1988; Carolyn Miller, 1992).

3 For more on to prepon see John Poulakos, 1983.

4 Expertise is not exactly the same thing as ethos, though expertise is a kind of ethos. See Geisler, 1992; Carter, 1990. These articles put forth different descriptions of the qualities of expertise. William Rifkin (1989) has developed a theory of expert status as a negotiated concept.

5 Steve Fuller refers to such universal languages as "pidgins," which sometimes evolve from trading zones. He points to Monte Carlo that evolved out of the pooling of expertise and continues to be a body of research to which several disciplines contribute (Fuller, 1993: 45).

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Migrating Across Disciplinary Boundaries:
The Case of David Raup's and John Sepkoski's Periodicity Papers

Dale L. Sullivan

Book Contents

Migrating Across Disciplinary Boundaries