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Catastrophism

Catastrophism

, an idea that emerged at the begin­ning of the 18th century, holds that the has been affected by a series of sudden, short-lived, vio­lent events (such as land upheavals and floods that may have been worldwide in scope). These catastro­phes, or “revolutions,” shaped the earth’s surface, forming mountains and valleys, and at the same time destroyed whole species of organisms, some specimens of which were preserved as fossils. After each catastrophe, entirely different life forms repop­ulated the earth, either by migration or because life emerged again, which would explain the differences in fossil forms encountered in successive strati­graphic levels. Initially, this could be a way to ratio­nalize first field observations with an assumed short history of the earth and the decisively established organic origin of fossils as vestiges of ancient beings. However, a dynamics of paroxysm did not require catastrophists to hold to a limited geological time for the age of the earth. Many catastrophists believed that the earth was millions of years old and still concentrating its major changes on brief rup­tures. The earth today was viewed as the result of an accumulation of catastrophic events, which articu­late a directional history of the earth and life. Many scientists and historians regard directionalism more as a central theme than the dynamics of paroxysm and, consequently, some scholars redesignate catas­trophism as a “directionalist synthesis.”

Origins of Catastrophism

The Swiss naturalist Charles Bonnet (1720-1793) was the precursor of catastrophism. In his work Principles of Catastrophism, he suggested that all living things have been destroyed by catastrophes at periodic intervals throughout the earth’s history and they themselves accounted for fossils. Bonnet was the first to use the term evolution in a biological sense. He believed that a new creation follows a catastrophic event in which new life forms could elevate one level in the Great Chain of Being (the influential concept that all of nature, from nonliving matter to sophisticated organisms to spiritual beings, is arranged in an unbroken physical and metaphysical series or hierarchy).

Catastrophism, however, is generally associated with the great French anatomist and paleontologist Baron (1769-1832). Cuvier is credited with applying his anatomical principle of the “correlation of parts” in the systematic study of fossil vertebrates to arrive at his most memorable discovery: that species of animals have indeed become extinct. Cuvier reconstructs the skeleton of fossil tetrapods (mainly large mammals) from isolated bones by gathering together and re-creating lost skeletal elements, given that the anatomical structure of every organ is functionally related to all other organs in the body of an animal because animals interact with their environment, resulting in the functional and structural characteristics of their organs. He concluded that these large terrestrial vertebrates had become extinct, based on the fact that their skeletons are very different from those of present-day species, which were very well known on all continents; and given the unlikelihood of discovering new ones. To explain the patterns of extinction and faunal succession in the fossil record and the alternations of marine and continental sedimentary strata that he himself had registered, Cuvier argued that sudden land upheavals and inundation of low-lying areas by the sea might have been responsible for the most recent extinctions in Eurasia. He viewed these revolutions as naturally recurring events, subsequent to long intervals of stability during the history of life on Earth, and this led him to enumerate successive ages down into the sequence of strata indicated by the fossil animals that they contain. Timewise, the history of the earth had been indefinitely long. At the same time, Cuvier expresses the directionality of geological history. Following the Wernerian system, he argues in favor of systematically changing mineralogy throughout time, and for a pattern of decreasing effect or intensity of catastrophes, as an original universal ocean gets smaller. Thus catastrophic dynamics and directionality are interconnected in a distinctive and comprehensive view.

Cuvier also affirms directionality when he remarks that fossils from successively older strata become increasingly more different from modern species, and thus ever more “primitive” by the conventional definition of progress. However, in Cuvier’s view, species were immutable (fixed). Faced with bitter opposition to the evolutionary ideas of Jean-Baptiste Lamarck (1744-1829), his major argument was that mummified cats and ibises (brought to Paris by Napoleon’s expedition to Egypt) showed that no transformations had taken place in 3,000 years. Cuvier also argued that each species is so well coordinated, both functionally and structurally, that it could not have survived significant change. Ironically, Cuvier’s lifework is considered as marking a tran­sition between the 18th-century view of nature and the view that emerged in the second half of the 19th century as a result of the doctrine of evo­lution. By rejecting the Chain of Being in favor of classifying animals in four separate groups (verte­brates, mollusks, articulates, and radiates), each of which had a special type of anatomical organi­zation, he raised the key question of why animals were anatomically different.

Catastrophism Versus

Catastrophism was the dominant paradigm of geol­ogy until uniformitarianism became commonly accepted. Because catastrophism was more easily associated with religious doctrines, it greatly over­shadowed the opposing uniformitarian ideas of James Hutton (1726-1797) that slow changes over long periods of time could explain the features of the earth. The dominant belief in many cultures about the creation and development of the world was essentially catastrophist. The finest example of these beliefs is the biblical account of the Great Flood, whose influence on scientific thinking per­sisted up to the threshold of the 19th century. Cuvier gave credence to his concept of catastroph­ism in 1812 in the essay “Discours preliminaire” (which he included in his “Recherches sur les osse- ments fossiles de quadrupeds”) as well as in the expansion of this essay into book form in 1825, “Discours sur les revolutions de la surface du globe,” the most important of all catastrophist texts. Cuvier’s essay was very influential in England, where natural theology was dominant during the early 19th century. A group of geologists that included William Buckland (1784-1856) and Robert Jameson (1774-1854) misinterpreted Cuvier’s ideas and explained catastrophism in a very different way. Jameson translated Cuvier’s essay and published it under the title “Essay on the .” He added extensive editorial notes to the translation that explicitly linked the lat­est of Cuvier’s revolutions with the biblical flood, and the resulting text was extremely influential in the English-speaking world. Buckland spent much of his early career trying to demonstrate the reality of the Noachian flood with geological evidence, and he frequently cited Cuvier but misinterpreted his work. As a result of the influence of these and other advocates of natural theology, the 19th-century debate over catastrophism took on religious con­notations in Britain that were not nearly as promi­nent elsewhere. Catastrophism became a bastion of ecclesiastical reactionaries in a vain effort to stem the inexorable advance of the natural sciences.

From around 1850 to 1980 most geologists endorsed uniformitarianism, thanks to the fact that it was clearly and concisely explained by (1797-1875) but also because Lyell, a lawyer by profession, discredited catastrophism as a viable explanation of geological phenomena. Cuvier’s catastrophism, which was widely spread by means of the distorted views of natural theology, was placed beyond the pale of scientific respectability by Lyell’s rhetoric that falsely attributed to him two major charges that he had not made (and that still persist in recent textbooks). For Lyell, catas- trophist became “a boundless field for speculation” that could “never rise to the rank of an exact .” Cuvier’s essay, however, exposes all characteristic features of catastrophism as a sci­ence. It is an irony of history that Cuvier, one of the greatest intellectuals of 19th-century science and a champion of rationality, as well as other catastrophists, should become an object of ridicule without being read.

The Enlightenment and the intellectual climate of the Revolution influenced French thinkers and sci­entists, who, after a long period in which science was dominated by tradition, irrationality, and superstition believed that systematic thinking applied to all areas of knowledge could lead to the progress of ideas. Influenced by these ideas, Cuvier avoided religious or metaphysical speculation in his scientific writings, but he was also habituated to processes of dramatic and discontinuous upheaval by life experi­ences of The Reign of Terror (during the French Revolution). He made no reference to divine cre­ation as the mechanism by which repopulation occurred following the extinction event. By contrast, he appointed the migration of surviving animals in isolated areas as the plausible mechanism. Nor did he make any explicit reference that the most recent revolution corresponded to the biblical flood. It is true that Cuvier paid special attention to the last revolution, concluding that it cannot be dated much farther back than 5 or 6 thousand years. He actually noted that no human fossils existed at all in the countries where the vertebrate fossil bones are dis­covered; however, as it is assumed that the last catastrophe occurred within human memory, he scanned the oldest records of all cultures and thus coordinated two sources of evidence, natural history for estimating the effect of ordinary causes since the last paroxysm and civil history. Since Western cultures recorded this event as Noah’s Flood, and since Cuvier used the Bible as one source of legiti­mate historical information among many, posterity charged him with distorting geological facts to sup­port religious traditionalism. However, his empirical hope was to understand catastrophes through a detailed study of the most recent event, the most suitable for this goal given the fragmentary nature of geological evidence and the tendency for such evi­dence to become more and more inadequate as we penetrated deeper into time.

Some textbooks have erroneously regarded Lyell as an empiricist who, by fieldwork and close attention to objective information, drove the dog­matism of catastrophists out of science. On the contrary, the catastrophists advocated empirical literalism as a fundamental approach to science. They interpreted what they observed as a true and accurate record of actual events and interpolated nothing. Early geologists and paleontologists noted that breaks or ruptures appeared frequently in the geological record when they studied the structure of the mountains. For instance, it is usually observed that deformed layers containing marine fossils may be truncated and overlain by other horizontal beds also containing marine fossils but that are entirely different from the previous ones. Applying the law of superposition and the princi­ple of original horizontality, the defining principles of stratigraphy already established during the 17th century, these were interpreted by geologists as two rock masses or strata of different ages that appear separated by a surface indicating that sedi­ment deposition was not continuous, the strata above the surface being younger than the strata below (unless the sequence has been overturned), and that folding and/or faulting of older strata occurred prior to deposition under the sea of the younger strata. This discontinuity evidences an event that catastrophists interpreted as paroxysmal to deform the original horizontal strata and eradi­cate the older fauna. Uniformitarian geology, how­ever, interpreted the folding and/or faulting of older strata and their elevation above the sea as associated processes that occur so slowly that we cannot appreciate the changes within a human perspective. Equally, the surface between both rock masses was formed through subaerial expo­sure and erosion over a very long time, representing a gap in the record that could cover several millions of years. According to Lyell, catastrophists misin­terpreted the massive lacunae as evidence for rapid change. Geological unconformities and local extinction look paroxysmal, but only because slow, daily changes rarely leave any evidentiary trace at all. In his view, the geological record must be treated as imperfect to an extreme degree. Proper procedure in geology requires interpolating into a systematically impoverished record the unpreserved events implied by our best theoretical understanding.

Recent Theories

In the last decades of the 20th century a revival of Cuvier’s catastrophism, a neo-catastrophic school, gained wide acceptance with regard to certain events (such as the mass extinctions) in the distant past. One stimulus for this change was the work of Walter and Luis Alvarez who in 1980 suggested that an asteroid struck Earth 65 million years ago, at the end of the Cretaceous period, and caused a mass extinction in which 70% of all species, including the dinosaurs, disappeared. In 1990, a 180-kilometer candidate crater marking such an impact was identified at Chicxulub in the Yucatan Peninsula of Mexico. The improbability of such an event is no argument against such a hypothesis, because the improbable, even with odds of once every billion years, must have taken place a few times in geological history. The sedimentological importance of rare events is difficult to assess because the record of such events may be very sub­tle. This is especially true if a deposit has been thor­oughly bioturbated or if the record of an event is simply an erosional surface. Moreover, we know now that catastrophic events occur as natural events, as was illustrated by the observation of the Shoemaker-Levy 9 cometary collision with Jupiter. Since then, most of the mechanisms suggested to explain mass extinction events have been cata­strophic in nature.

Thus, new theories such as actualistic catastro­phism or episodic sedimentation, and disciplines like Event Stratigraphy and Cyclostratigraphy, developed in the geoscience community, represent a synthesis of Lyell’s uniformitarianism combined with Cuvier’s catastrophism. They are founded on the assumption that the earth as we know it today has been shaped by slow natural processes, but that most of the stratigraphic record was produced during cyclic and episodic astronomically forced events that were disturbed by other occasional natural catastrophic events such as bolide impacts or cataclysmic volcanic activity, which have pro­duced abrupt environmental changes that have greatly affected the evolution of life on Earth. The immensity of geological time is important not only because of the immensity of the cumulative effects, but also because the long duration provides a chance for the improbable to take place.

This conceptual change in during the last third of the 20th century also pro­duced new theories, such as punctuated equilib­rium and a revival of saltationism, that posit that evolution among the species takes place in rapid bursts separated by long periods in which little change occurs. These ideas contrast with Darwin’s gradualism that, influenced by Lyell’s uniformi­tarianism, requires that the fossil record be imper­fect to interpolate the intermediate forms that, as Cuvier explicitly noted, have never been found.

See also Chicxulub Crater; Charles Darwin; Dinosaurs; Age of Earth; Erosion;  Organic; Extinction Evolution; Extinction and Evolution; Mass Extinctions; Fossil Record; Interpretations of Fossils; Geology; James Hutton; K-T Boundary; Charles Lyell; Noah; Paleontology; Stratigraphy; Uniformitarianism

Further Readings

Briggs J. C. (1998). Biotic replacements: Extinction or clade interaction? BioScience, 48(5), 389-395.

Dott, R. H. (1983). Episodic sedimentation: How normal is average? How rare is rare? Does it matter? Journal of Sedimentary Research, 53(1), 5-23

Gould, S. J. (2002). The structure of evolutionary theory (p. 1464). Cambridge, MA: Harvard University Press.

Hsü, K. J. (1989). Catastrophic extinctions and the inevitability of the improbable. Journal of the Geological Society, 146(5), 749-754.

Koutsoukos, E. (Ed.). (2005). Applied stratigraphy. Topics in Geobiology, 23, 488.

Oldroyd, D. (1996). Thinking about the earth: A history of ideas in geology (p. 440). Cambridge, MA: Harvard University Press.

Palmer, T. (2003). Perilous planet Earth: Catastrophes and catastrophism through the ages. Cambridge, UK: Cambridge University Press.

Rudwick, M. J. S. (2005). Bursting the limits of time: The reconstruction of geohistory in the age of revolution. Chicago: University of Chicago Press.

Virgili, C. (2007). Charles Lyell and scientific thinking in geology. Comptes Rendus Geoscience, 339(8), 572-584.

Wicander, R., & Monroe J. S. (2003). : Evolution of earth and life through time (4th ed.). London: Brooks/Cole.

York, R., & Brett, C. (2005). Natural history and the nature of history. Monthly Review, 57(7), 21-29.

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