Punctuated Equilibrium as metaphor

Beloved paleontologist and essayist Stephan Jay Gould often struggled with the idea of progress that haunted the pages of Charles Darwin’s On the Origins of Species. For many historians of science, and for Gould himself, Darwin’s belief that the current, living, plethora of species were more advanced forms of their extinct relatives, is most likely inspired by a fundamental assumption of the Victorian upper-class: that those at the top, both in nature and society, advanced due to their particular advantage, allowing them to succeed where others failed. In this view, life and society, were rationalized (rather than reasoned) as steady races, progressing toward that that goal, that more specialized, proficient victor.

Painting by Heinrich Harder

But we should not flippantly reduce this powerful notion of progress to sociology psychology. It is infused into almost every discipline and, within evolution, is understandable given the stratification of the fossil record. It is possible to understand the 35 million year old Mesohippus as an “early horse,” and the present riding horse (Equus ferus caballus) as the resultant of steady improvements on that older, more “basic” organism. Similarly, a progressive evolutionary theory formulates the Ambulocetus as a primitive “walking whale”, even though it was four-legged, but it was only mere steps away from having the advantage of flippers.

[Crump’s A Brief History of Science as Seen Though the Development of Scientific Instruments (2001), is saturated with such formulations of progress in respect to the “fitness” of our science…]

The fossil record, however, would come to resist the formulation of progressive evolution. There are rich fossil deposits at the Burgess Shale in British Columbia, demonstrating that, 530 million years ago, there were radically diverse and complex organisms of which there are neither newer, nor more advanced, descendents.

[…even though Butterfield had exercised many of those demons from the writing of history in 1931.2]

In fact, extinction is a phenomenon that seems to most violently push back against theories of evolutionary progress, specifically because it presents us with scenarios in which organisms are confronted with obstacles they can neither anticipate nor overcome through the gifts of gradual, progressive change.

[The work of philosopher Michel Foucault occupies itself with the emergence and disappearance of epistemological entities within the ecology of knowledge: objects, subjects, concepts, rules, etc. All these forms of emergence are also ways of enclosing thought, of making that attend-able. The emergence of an articulation, a part or portion, from an unarticulated background or complexity marks-off that entity as something. This requires tracing and philsophical excavation. Thus we call Foucault’s investigations archaeologies and genealogies of a knowledge, a knowledge which is discontinuous.]

When the Burgess Shale fossils were discovered by Charles Walcott in 1909, the fossils were understood through Darwin’s narrative of progress, and categorized as bizarre ancestors of established taxonomic categories.

[Self-consciously, an anachronistic reading of a text can create meaning: philosophical hermeneutics insists that we carry the present with us when turn to the past. When such an anachronistic reading is done “half-aware,” anachronism allows us to judge and assign value to the past, within reason. However, when anachronism is unaware of itself, the reader becomes a panicked marauder scrambling for value, destroying a priceless scroll in order to steal its silver container.]

Take, for example, Marrella splendens, a tiny, 530-million-year-old arthropod, who sported a large head chest and many feathery gills and legs. It was the first of Walcott’s discoveries, and the most prominent of the Shale’s residents. For Walcott, Marrella had to be a primitive form of trilobite; it was the only possible lineage in which it would fit. It wouldn’t fit anywhere else in the taxonomy.

[When attention is pushed to the limits of abstraction, it names the emergence and manipulation of enclosures, a function of spatialized thought: the distinctions between inside and outside, this and that, is and is not. Yet, each event of attention radically re-negotiates those limits.]

But Marrella wouldn’t exist as a trilobite for forever. Not only did the Marrella not fit anywhere within the established taxonomic classifications of the early 1900s, there were no known organisms in 1909 could explain Marrella’s “role” in a story of progressive evolution. The Burgess Shale is full of such creatures from nowhere.

[Nothing is ever really closed off. Niholas Luhmann, the Great German thinker of social systems, maintains that in order for any system to function, it must take inside that which is outside.4 There must be a function of “novelty”, the new, where something foreign enters into the established. This constitutes time. Without the new there is no temporal dimension of the system. And, systems that become completely closed off, without a function of novelty, cease to function completely; without functionality, there is no system, whether we’re speaking of car engines, bird populations, or the economy.]

It was only after close re-examination in 1971, that the complexity and specificity of Marrella, and the other Burgess Shale’s anomalies could be recast according to a different evolutionary movement than that of gradual progress.

For Stephan Jay Gould, the fossil record and the phenomena of extinction provide patterns which suggest the historical movement of species generation, differentiation and extinction was of punctuated equilibrium: fluctuations of diversity and discontinuities in evolutionary linage throughout time. Not gradual. Not progressive. Rather, within the complexity of ecology there are long periods of relatively low evolutionary activity (equilibrium), where very few changes occur. Then, there are punctuations, massive explosions within the diversity in life, and catastrophic extinction events that decimate it.

[The stratification and transformation of knowledge may not be a matter of perfecting premises, narrowing scopes, or locating final causes. Rather, the movements of knowledge may be a matter of thresholds, of bifurcations. Punctuated equilibrium. Not a ladder, but a lattice.]


One thought on “Punctuated Equilibrium as metaphor

  1. Pingback: The Giant’s Shoulders #36: The ABCs of the History of Science « The Dispersal of Darwin

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