Since a coordinating vector of temporal cooling generates the entire system, and since many scientists and historians regard the theme of directionalism as even more central than the dynamics of paroxysm, several scholars have urged, in recent years, that the entire movement be redesignated as the “directionalist synthesis,” rather than “catastrophism.” The major “catastrophists” never defined themselves as a school opposed to a dichotomous Lyellian alternative, and therefore never gave their movement a name. The construction of such a dichotomy, with moral values attached to each side, set a major aspect of Lyell's rhetorical strategy.
Methodologically, all leading catastrophists adopted a distinctive attitude towards the geological record. They preached a radical empirical literalism: interpret what you see as a true and accurate record of actual events, and interpolate nothing. If horizontal strata overlie a sequence of broken and tilted beds, then a catastrophe must have terminated one world and initiated another, as the geological discontinuity implies. If one fauna disappeared at such a boundary, and younger beds contain fossils of different creatures, then a mass extinction must have eradicated the older fauna. The catastrophists advocated directionalism as a primary theme for the earth's history, and empirical literalism as a fundamental approach to science.
How ironic, then, that modern textbook cardboard should misidentify Lyell as an empiricist who, by laborious fieldwork and close attention to objective information, drove the dogmatists of catastrophism out of science. To the contrary, the catastrophists were the empirical literalists of their time! Lyell and Darwin opposed catastrophism by probing “behind appearance” to interpret, rather than simply to record, the data of geology. For Lyell and Darwin, the geological record must be treated as imperfect to an extreme degree — in the standard metaphor developed by Lyell and propagated by Darwin, like a book with few pages preserved and only a few letters surviving on each of these pages. Moreover, Lyell argued, the geological record has also become distorted in a systematic way that would foster a false concept of change if we attempted a literal reading. Geological unconformities and local extinctions look paroxysmal, but only because slow, daily changes rarely leave any evidentiary trace at all. We therefore can observe only the infrequently preserved waystations of a true continuity, and we misinterpret the massive lacunae as evidence for rapid change. If, to cite Lyell's example, Vesuvius erupted again and buried a modern Italian town directly atop Pompeii, would we interpret history by the literal evidence of a Latin culture suddenly extirpated in a (potentially global) episode of volcanism, then followed by the saltational origin of a distinct, but clearly allied, Italian civilization, accompanied by such new cultural artifacts as beer cans and electric bulbs?
Proper procedure in geology, Lyell asserted, requires that we interpolate into a systematically impoverished record the unpreserved events implied by our best theoretical understanding. Lyell and Darwin worked by interpretation [Page 486] and interpolation; the catastrophists preached empirical literalism! (I do not raise this issue to denigrate Lyell and Darwin, for I support their procedure as a general statement about scientific methodology. Slavish literalism should be shunned in general, and not only (as in this geological case) when we have reason to regard a preserved record as systematically imperfect. Still, I know no greater irony in the history of science than the inverted posthumous reputations awarded to Lyell and the catastrophists for their supposed positions on “objectivism” in science.)
In paleontology, catastrophism reached an apogee in Georges Cuvier's Discours preliminaire, originally written as a preface to his great four-volume compendium on fossil vertebrates (Recherches sur les ossemens fossiles, 1812), but published and republished separately as an “Essay on the theory of the earth.” Cuvier did not present his Essay as a textbook of catastrophism, but as a statement about the roles that paleontology and geology should play in unravelling the history of the earth. Nonetheless, Cuvier's Essay exposes all characteristic features of catastrophism as a science, and illustrates the incompatibility of this geological approach with Darwin's prerequisites for natural selection as a chief agent of macroevolutionary pattern.
On the substantive side of catastrophism, Cuvier devoted most attention to demonstrating life's temporal directionality, and to illustrating the value of such a vector for inferring geological history and stratigraphic order. As his greatest contribution, Cuvier proved that species could become extinct (a phenomenon still widely doubted at the inception of the 19th century). In his major source of evidence, Cuvier demonstrated that the anatomy of some fossil quadrupeds lay outside the boundaries of variation within modern species. He also traced a stratigraphic sequence of increasing similarity to modern faunas in successively younger beds, thus documenting a directional pattern within sequences of extinction, and providing the earth with a meaningful history. Cuvier begins the Essay by castigating his predecessors for combining their grandiose speculative theorizing with an inattention to fossils and their stratigraphic positions. He then presents his concept of proper procedure in the form of a list of questions, mostly centered upon historical pattern and direction in stratigraphy. “Are there certain animals and plants peculiar to certain strata, and not found in others? What are the species that appear first in order, and those, which succeed? Do these two kinds of species ever accompany one another? Are there alterations* in their appearances; or, in other words, does the first species appear a second time, and does the second species then disappear?” (1818, p. 65).
Cuvier's answer, leading to the birth of modern paleontology, affirms directionality in two senses: fossils from successively older strata become increasingly [Page 487] less like modern forms, and thus ever more “primitive” by conventional definitions of progress:
It is, in the first place, clearly ascertained, that the oviparous quadrupeds are found considerably earlier, or in more ancient strata, than those of the viviparous class . . . The most celebrated of the unknown species belonging to known genera, or to genera nearly allied to those that are known, as the fossil elephant, rhinoceros, hippopotamus, and mastodon, are never found along with the more ancient genera; but are only contained in alluvial formations . . . Lastly, the bones of species which are apparently the same with those that still exist alive, are never found except in the very latest alluvial depositions (1818, pp. 112-115).
Cuvier expresses a similar interest in the directionality of physical history. He argues (following the Wernerian system) for systematically changing mineralogy through time, and for a pattern of increasing restriction of effect, as an original and universal ocean shrinks, thus decreasing the intensity of catastrophes as well: “The sea has not always deposited stony substances of the same kind. It has observed a regular succession as to the nature of its deposits; the more ancient the strata are, so much the more uniform and extensive are they; and the more recent they are, the more limited are they, and the more variation is observed in them at small distances” (1818, p. 34).
Cuvier treats directionality as his principal theme, but the validation of catastrophe does not rank far behind, and the two subjects mesh into a distinctive and comprehensive view. Cuvier opens the Essay with an exposition of catastrophist dynamics. Interestingly, he begins, as Lyell did from the other side (and as good advocates so frequently do), with a potent rhetorical device: we see the world in an inherently biased way from our limited and daily perspective, but deeper investigation reveals that opposite forces prevail in the fullness of time. Lyell began by questioning our undue focus on civil catastrophes of death, famine and war, and by arguing that we overemphasize such tragedies as a consequence of their personal impact. We therefore fail to appreciate the far greater power of ordinary events to render history by accumulation through time. Cuvier, in reversed perspective, claims that we grant too much power to the calm of daily life because we live within its immediate, surrounding pervasiveness. We therefore fail to realize that rare an
d unusual events set the basic pattern of history. After a preliminary discussion about the data and power of natural history as a science, Cuvier begins his Essay with a striking image devised to equate catastrophism with a broad and generous vision of reality:
When the traveller passes through those fertile plains where gently-flowing streams nourish in their course an abundant vegetation, and where the soil, inhabited by a numerous population, adorned with flourishing villages, opulent cities, and superb monuments, is never disturbed except by the ravages of war and the oppression of tyrants, he is not led to suspect that nature also has had her intestine wars, and that the surface of [Page 488] the globe has been much convulsed by successive revolutions and various catastrophes. But his ideas change as soon as he digs into that soil which presents such a peaceful aspect, or ascends the hills which border the plain; they are expanded, if I may use the expression, in proportion to the expansion of his view; and they begin to embrace the full extent and grandeur of those ancient events (pp. 29-30).
The next several sections of the Essay present, in sequence, a framework for regarding catastrophe as the primary agent of geological change — “proofs of revolutions”; “proofs that revolutions have been numerous”; “proofs that revolutions have been sudden”; “proofs of the occurrence of revolutions before the existence of living beings.” Cuvier then examines, as Lyell did but to reach an opposite conclusion, the efficacy of modern causes, declaring them insufficient to render the events of catastrophic episodes. Cuvier's words — in the most famous passage of his entire oeuvre — have usually been cited out of context, to equate catastrophism with despair and even with hostility to scientific explanation. But, clearly, Cuvier harbored no such intent. He does express some regret at the discordance between catastrophic and daily causes — for the task of science would become easier if present forces sufficed. But the significance of the geological record lies in its potential for documenting the catastrophic causes:
It has long been considered possible to explain the more ancient revolutions on its surface by means of these still existing causes; in the same manner as it is found easy to explain past events in political history, by an acquaintance with the passions and intrigues of the present day. But we shall presently see that unfortunately this is not the case in physical history; the thread of operation is here broken, the march of nature is changed, and none of the agents that she now employs were sufficient for the production of her ancient works [or, to cite Cuvier's most famous line in its French original — le fil des operations est rompu; la marche de la nature est changee; et aucun des agens qu'elle emploie aujourd'hui ne lui auroit suffi pour produire ses anciens ouvrages] (1818, p. 44; 1812, P. 17).
Note Cuvier's careful choice of words. He does not appeal to mystery by stating that current causes didn't work in an uninterpretable past; rather, he deems modern causes insufficient to explain the evidence for historical catastrophes. We must therefore study the geological record directly if we wish to resolve the causes of catastrophes. I find nothing objectionable, or contrary to good scientific methodology, in this argument.
Cuvier summarizes the substantive part of his Essay in a paragraph that unites catastrophe with directionality, and the physical record with the biological history of the earth:
Life, therefore, has been often disturbed on this earth by terrible events — calamities which, at their commencement, have perhaps moved and overturned to a great depth the entire outer crust of the globe, but [Page 489] which, since these first commotions, have uniformly acted at a less depth [sic] and less generally. Numberless living beings have been the victims of these catastrophes; some have been destroyed by sudden inundations, others have been laid dry in consequence of the bottom of the seas being instantaneously elevated. Their races even have become extinct, and have left no memorial of them except some small fragment, which the naturalist can scarcely recognize (1818, p. 38).
The last line of this quotation helps to explain the longest and most brilliant (though ultimately incorrect) final section of the Essay — the source of so much misunderstanding about Cuvier, and about catastrophism. Given the fragmentary nature of geological evidence, and the tendency for such evidence to become more and more inadequate as we penetrate deeper into time, our best empirical hope for understanding catastrophes lies in a detailed study of the most recent event. By coordinating two sources of evidence — natural history for estimating the effect of ordinary causes since the last paroxysm, and civil history (because the last catastrophe occurred within human memory) — we might characterize at least one event well enough to build a model for the generality. Cuvier therefore scans the oldest records of all cultures, rejecting some as fabulous, adjusting and coordinating others, and finally reaching the conclusion that “the crust of our globe has been subjected to a great and sudden revolution, the epoch of which cannot be dated much farther back than five or six thousand years ago” (1818, p. 166). Since Western culture recorded this event as Noah's flood, and since Cuvier used the Bible as one source of information about this episode, posterity has interpreted this section of the Essay as a tortured exercise in Christian apologetics — thus affirming the usual interpretation of catastrophism as theological reaction.
But Cuvier proceeds with a precisely opposite intent, and his Essay therefore becomes a seminal work of Enlightenment humanism. Cuvier does not marshall geological and civil history to support the biblical account of Noah's flood; rather, he uses the Old Testament as one source among many in a broad effort to unite the traditions of disparate fields towards a common intellectual goal. Of course Cuvier cites the Bible — as one legitimate source for making historical inferences, but with no favored status. Cuvier pays as much attention to the traditions of the Assyrians, the Parsis and the Hindus, and he grants even more credence to the records of ancient China. His evidence for the last catastrophe does not rest upon scriptural assertion, but on a supposed confluence of differing empirical sources, as the lengthy title for this chapter of the Essay proclaims: “The concurrence of historical and traditionary testimonies, respecting a comparatively recent renewal of the human race, and their agreement with the proofs that are furnished by the operations of nature.”
Cuvier's Essay also stresses the methodology of catastrophism, particularly the empirical literalism of its favored approach to the geological record. Cuvier, even more strongly than Lyell, dismisses the speculative tradition pursued by previous generations, with their grandiloquent claims for comprehensive [Page 490] grasp, but so little attention paid to facts of the stratigraphic record. (Cuvier even includes Lyell's hero, James Hutton, among the speculative system builders, though praising him faintly for proceeding “with more caution.”) True scientific progress now demands a methodological revolt — a scaling down of explanatory focus from fuzzy and grand theorizing to immediate and palpable observation, a move from the armchair to the field and museum. Progress also demands the specific coordination of two empirical sources — stratigraphic succession as documented by fieldwork, and taxonomic knowledge of organic diversity as revealed in large museum collections. We may designate the knowledge of causes as our final goal, but we must proceed by voluminous and coordinated study of the empirical record:
If, from the want of sufficient evidence, these questions cannot be satisfactorily answered, how shall we be able to explain the causes of the presently existing state of our globe ... Naturalists seem to have scarcely any idea of the propriety of investigating facts before they construct their systems. The cause of this strange procedure may be discovered by considering that all geologists hitherto have either been mere cabinet naturalists, who had themselves hardly paid any attention to the structure of mountains, or mere mineralogists, who had not studied in sufficient detail the innumerable diversity of animals, and the almost infinite complexity of their various parts and organs. The former of these have only constructed systems; while the latter have made excellent colle
ctions of observations, and have laid the foundations of true geological science, but have been unable to raise and complete the edifice (1818, pp. 66-67).
Cuvier's unwillingness to proceed much beyond immediate data deprives the Essay of any “grand” conclusion — perhaps for the better. Cuvier never specifies how the two substantive themes of directionalism and successive catastrophes might unite to forge a general theory of the earth's behavior. He presents no proposal, like Elie de Beaumont's of later years, for a general theory of planetary dynamics. Cuvier's final section includes no general summary, no stirring plea for ultimate solutions, but only presents some practical suggestions for fruitful empirical work, accompanied by a list of potential examples. We should now focus, Cuvier argues, not on the most recent strata (which have been intensely studied already), and not on the earth's beginnings (which remain too distant and too different for adequate resolution), but on fossiliferous rocks of intermediate age — on the gypsum quarries of Aix, the sand-hills of the Apennines, and the “stinkstone slate of Oeningen.” “It appears to me,” Cuvier concludes, “that a consecutive history of such singular deposits would be infinitely more valuable than so many contradictory conjectures respecting the first origin of the world and other planets and respecting phenomena which have confessedly no resemblance whatever to those of the present physical state of the world” (1818, p. 173).
Lyell would not have disagreed with these sentiments; homilies about the primacy of observation, after all, top the list of clichés in scientific prose. As [Page 491] their primary query, both Cuvier and Lyell asked not whether, but rather how, science should treat the empirics of the geological record — and Cuvier's chief difference with Lyell and Darwin centered upon his empirical literalism versus their commitment to probing behind the appearances of a systematically imperfect record. A dramatic example of this distinction occurs at a key point in Cuvier's Essay, and serves to illustrate the real and continuing contrast between legitimate themes in catastrophism versus Darwin's need for a uniformitarian geology based upon the accumulation of small effects. In Section 30 on “proofs that the extinct species of quadrupeds are not varieties of the presently existing species,” Cuvier considers a potential argument against the reality of mass extinctions produced by geological catastrophes. No one can deny that many fossil quadrupeds represent species no longer living — for Cuvier had proved this point beyond a doubt. Only one logical alternative therefore remained to challenge Cuvier's own conclusion that these ancient species had perished — namely, evolution. Perhaps these forms never died, but gradually changed into different species now extant. Lamarck, Cuvier's closest colleague, had been advocating this idea for more than a decade, and straining their former friendship thereby (see Chapter 3). But Cuvier replied with an empirical rejoinder that could scarcely be gainsaid so long as the fossil record could be treated as literally accurate. No intermediary forms have been found as fossils, while new species occur in strata directly atop the doomed faunas:
The Structure of Evolutionary Theory Page 78
