Richard Delisle

The label “Darwinism” has been with us for so long that it seems totally unreasonable to propose to dispose of it. Yet, we maintain it has outlived its utility in so far as it acts more like a distorting lens than as a magnifying one. This will be illustrated by investigating the notion of “evolutionary contingency” in Charles Darwin, Ernst Mayr, and Stephen Jay Gould. It is a common assumption of the received view that Darwinism is consubstantial with the idea of an open-ended evolutionary process in time. However, Darwin’s many commitments toward uniformitarianism seriously limited his understanding of evolutionary contingency, while the early Mayr (roughly between 1940 and 1970) stayed too close from this forgotten Darwin to fully engage with it (notwithstanding his rhetoric to the contrary). Indeed, the way Darwin and Mayr exploited the principle of divergence closed off several open avenues to evolutionary change, thus channeling the expression of contingency. For his part, Gould made a significant contribution toward a more robust appreciation of evolutionary contingency (a view partly supported by the late Mayr (1990–2005) who by that time had retreated significantly from his earlier view), although Gould’s justification has its intellectual roots in a mythical Darwin that never existed. Evolutionary contingency has thus far played the role of a blanket notion artificially uniting “Darwinism” and obscuring important features part of Darwin’s, Mayr’s, and Gould’s brands of biology. Our analysis points to the usefulness of distinguishing between competing ontologies of evolutionary time.

It is not uncommon to see in major areas of research concerned with science that historical studies are accompanied by the rise of complementary or contradictory historiographies. With time, it seems, scholars discover new approaches to study topics, thus questioning old concepts, traditions, periodizations and historical labels. Apparently, this has not been the case in evolutionary thought. In that area, the main historiographic labels such as Darwinian Revolution, Eclipse of Darwinism, and Modern Synthesis have been in place and largely uncontested for about 50 years. Such labels seem to work as irrefutable, and often hidden, premises of many historical reconstructions, philosophical analyses, and scientific conceptualizations. This volume aims to move beyond this state of affair, opening new thinking avenues by revisiting the traditional historiography and laying the groundwork for establishing a “new historiography” that considers the intertwined threads that compose evolutionary biology. Notably, evolutionary studies seem to have been marked by the tension between unification attempts and the proliferation of approaches, methodologies, and styles of thinking. As the contributors to this volume illustrate, research traditions branched off throughout the history of evolutionary thought, before and after Charles Darwin. The resulting complexity challenges traditional thinking categories, throwing a somewhat different light on a more recent label like the Extended Evolutionary Synthesis. More than 40 years after the now classic, The Evolutionary Synthesis: Perspectives on the Unification of Biology (1980), edited by Ernst Mayr and William Provine, the contributors to this volume aim to reevaluate where evolutionary biology stands today.

This chapter provides an overview of many issues to be further developed in the rest of this book. In contradiction to the common assumption that the Origin of Species constitutes a contribution to universal evolutionism, it is argued that one finds at the core of Darwin’s magnum opus an explanatory structure congenial to a static worldview. This is reflected in several key assumptions: (1) the evolutionary past is imagined by projecting extant forms backward in geological time; (2) the unity of the tree of life is denied and replaced by isolated and segmented entities called classes or phyla, each having its own independent evolutionary history; and (3) classes and phyla are believed to be largely modern-looking as far back in time as one can probe. Given such commitments, it is no surprise that Darwin was unable to complete his transition to universal evolutionism successfully. With James Hutton, Charles Lyell, Thomas Henry Huxley, and Richard Owen, Charles Darwin assumed that the world had long been fully constituted. This view emerges more clearly if the reader is willing to go beyond Darwin’s rhetoric in the Origin.

Charles Darwin believed in biological progress. Yet many modern scholars puzzled over how this belief could be compatible with his theory which, presumably, was based on “evolutionary opportunism.” We hold that the puzzle is even more problematic for the opposite reason: whereas evolutionary opportunism might eventually have found the ways to progress, Darwin ultimately deprived the evolutionary process of flexibility by confining it within the straitjacket of a rigid and pre-established pan-divergent pattern. In addition, having constrained evolution within nearly stable and permanent classes/phyla, Darwin restricted evolutionary motion to lower taxonomic entities, envisioning them as falling under endless cycles of rising and declining forms. At a very fundamental explanatory level, Darwin’s view appealed to an equilibrium system built around devices such as (1) demographic expansion performed at the proportional expense of demographic decline; (2) an evolutionary drive involving related forms that exhausts itself in reverse proportion to their taxonomic ascent; and (3) an evolutionary stalemate maintained between forms interlocked in a mutual adaptive deadlock. The biological progress recognized by Darwin does not ensue from the application of his theory; rather, it is an empirical fact that his theory cannot explain.

Among scholars, Charles Darwin has often played the mythical role of a founding figure, one who must be either invoked or repudiated. In light of the analysis provided in this book, we argue that many of the notions Darwin employs—common ancestry, divergence, a self-regulated economy, evolutionary contingency, adaptation, natural selection, etc.—are incompatible with their uses in modern biology. Not only does modern evolutionary biology not originate with the Origin of Species, it also seems that the historiographical label “Darwinian Revolution” is largely without historical basis.

In Chapters 11 and 12 of the Origin of Species (as well as in Chapters 9 and 10), Darwin is busy refocusing his theory on the principle of divergence, after his theoretical drift in Chapters 6 and 7. This is done through investigations of closely related forms at low taxonomic levels assumed to have been derived from unique centers of dispersal. Yet, a close inspection of Darwin’s approach reveals his pan-divergent view of evolution was too rigid to accommodate the full complexity of evolution, forcing him to give up on the strong contingency thesis in favor of a much weaker version. This is seen in Darwin’s attempt to fit the pattern-process of evolution in an ideal model in which explanatory variables are symmetrically organized, whereby a certain quantity of geological time is proportional to a certain level of taxonomic separation; a certain distance in geographical space is proportional to a certain amount of selective pressure; a certain level of taxonomic separation is proportional to a certain distance in geographical space, and so on. What Darwin was pursuing was the preservation of the core of his theory: the twin principles of divergence-gradation. Owing to evolution’s complexity, however, it was not always possible for Darwin to subscribe to his ideal model, forcing him to adjust explanatory variables. An analysis of his utilization of this ideal model allows us to establish that Darwin’s theory contains two different components: (1) unmovable or irrefutable explanatory variables that could not be modified, since they formed part of the theory’s core (divergence and gradation), and (2) flexible variables that could be adjusted to protect the theory’s core through the postulated taxonomic level, the assumed geological depth, the geographical distance evaluated, and the selective pressure postulated. Darwin failed to make sense of the full complexity of evolution because he tried to save the core of his theory at all costs. For the same reason, we argue that “natural selection” is not part of his theory’s core, being merely an auxiliary explanatory component that should be jettisoned if necessary to protect that core.

With its twin focus on the mechanism of natural selection and the principle of divergence, Chapters 1–5 of the Origin of Species are often described as presenting the explanatory core of Darwin’s theory of evolution. Although Darwin might have pushed for this theoretical agenda, the critical reader willing to go beyond Darwin’s rhetoric encounters in them another dominant narrative. This alternative narrative sees life forms at low taxonomic levels as entangled in tight and complex reproductive networks from which it is difficult to break free considering, among other reasons, that nature does not favor inbreeding among forms that are too close and that life forms are dependent upon each other in multiple ways (symbiosis, coadaptation, predator-prey relationship, parasitism). An heir of the tradition of natural theology, Darwin’s intellectual toolkit was founded on such notions as contrivance (adaptation), interconnection (competition), and interdependence-symbiosis (harmony), which put him at a conceptual disadvantage when it came to reflecting upon the process-pattern of biological evolution. One gathers from Darwin’s exposition that life is less about neat irreversible divergent patterns propelled by a selective impetus than about complex genealogical strains and sub-breeds undergoing a perpetual fission-fusion process (reticulate evolution), a reality that blurs Darwin’s self-proclaimed proofs in favor of divergence. These contradictions bring to light the theory-laden character of Darwin’s account. In light of the solidarity of Chapter 8 of the Origin with Chapters 1–5, this former chapter will be included in our analysis here.

We argue that Charles Darwin’s methodological commitments in the Origin of Species which appeal to vera causa, uniformitarianism, gradualism, actualism, and extrapolationism constitute a conceptual nexus founded on an ontological commitment to a fully constituted world, that is, a homogeneous world unchanging over time, with the past and the present conceived as identical (the “steady-state view”). Ultimately, this ontology prevented Darwin from successfully completing the intellectual transition to full and modern evolutionism. In addition, because a steady-state world is best investigated through empirico-inductivism, this approach condemned Darwin to integrating too many facts that could not be explained under his so-called all-encompassing theory of evolution. Confronted with this ill-integrated pluralism, the reader of the Origin is left with an array of competing evolutionary pictures and theories.

Our image of Charles Darwin’s work has been modernized to excess by often presenting it as a contribution to modern evolutionism. Uncovering the real Darwin requires a recalibration of his image: seeing him afresh as a scholar in transition between two revolutions (the Scientific Revolution and the Transformist Revolution), two worldviews (the static and the evolutionary), and two epistemologies. In order to recast the Origin of Species against this complex canvas, an “intellectual grid” presenting fundamental ideas and dominant systems of thought is sketched. Our view of Darwin is situated in reference to the views of major Darwin scholars like John C. Greene, Michael Ruse, and Robert J. Richards. It is argued that the historiography needs to be completed by paying closer attention to Darwin’s profound debts to the static worldview developed in the seventeenth and eighteenth centuries.

More clearly than elsewhere in the Origin of Species, Chapter 13 attempts to propose a “consilience of inductions,” that is, an effort to gather support from a host of disciplines assumed to be pointing at the same explanatory core. Far from being a success on close inspection, Darwin’s attempt will assemble a long list of contradictory claims he himself provides by imposing upon these disciplines a number of simplifying assumptions about the pattern-process of evolution: (1) “divergence” and “common ancestry” are tightly associated; (2) generally speaking, the most divergent forms are said to be selected over less divergent ones; (3) it is assumed that divergence today is at its maximum relative to the evolutionary past of each class/phylum; and (4) the taxonomic arrangement observed among extant forms is believed to have persisted throughout the entire evolutionary history. Darwin’s assumptions overlooked the full complexity and openness of evolution by putting it in a conceptual straitjacket. Chapter 13 is the place where Darwin will deliver his ultimate fight against an evolutionary engine that erases its genealogical traces as it rolls on, thus generating all sorts of complexities, including the rise of similar features (analogies) and the complete deletion of traces in apparently ancestorless forms. We will conclude our analysis by providing an overview of Part II of our book (Chaps. 10.1007/978-3-030-17203-9_3–10.1007/978-3-030-17203-9_6), arguing that a close reading of the Origin reveals a series of different pictures of evolution, some of which are squarely inconsistent. The Origin of Species is far from offering a unified and all-encompassing theory of evolution.

Upon close inspection, Chapters 6 and 7 of the Origin of Species present a staggering spectacle. As often held, these chapters are about the postulation of intermediate evolutionary connections and the rise of complex organs from simple ones. But these explanatory components are put in the service of an entirely non-Darwinian theory of evolution, whereby life is depicted as a series of parallel and independent lines racing to acquire similar structures across evolutionary grades and taxonomic levels. Whereas Darwin’s theory requires a delicate balance between the “unity of type” (descent) and the “conditions of existence” (natural selection), Chapters 6 and 7 present natural selection as an untamed force annihilating traces of affiliation and generating evolutionary analogies. We argue that at least two incompatible theories of evolution exist side by side in the Origin of Species.

This book offers a thorough reanalysis of Charles Darwin's Origin of Species, which for many people represents the work that alone gave rise to evolutionism. Of course, scholars today know better than that. Yet, few resist the temptation of turning to the Origin in order to support it or reject it in light of their own work. Apparently, Darwin fills the mythical role of a founding figure that must either be invoked or repudiated. The book is an invitation to move beyond what is currently expected of Darwin's magnum opus. Once the rhetorical varnish of Darwin's discourses is removed, one discovers a work of remarkably indecisive conclusions. The book comprises two main theses: The Origin of Species never remotely achieved the theoretical unity to which it is often credited. Rather, Darwin was overwhelmed by a host of phenomena that could not fit into his narrow conceptual framework. In the Origin of Species, Darwin failed at completing the full conversion to evolutionism. Carrying many ill-designed intellectual tools of the 17th and 18th centuries, Darwin merely promoted a special brand of evolutionism, one that prevented him from taking the decisive steps toward an open and modern evolutionism. It makes an interesting read for biologists, historians and philosophers alike.

The 1920-1960 period saw the creation of the conditions for a unification of disciplines in the area of evolutionary biology under a limited number of theoretical prescriptions: the evolutionary synthesis. Whereas the sociological dimension of this synthesis was fairly successful, it was surprisingly loose when it came to the interpretation of the evolutionary mechanisms per se, and completely lacking at the level of the foundational epistemological and metaphysical commitments. Key figures such as Huxley, Simpson, Dobzhansky, and Rensch only paid lip service to the conceptual dimension of the evolutionary synthesis, as they eventually realized that a number of evolutionary phenomena could not be explained by its narrow theoretical corpus. Apparently, the evolutionary synthesis constituted a premature event in the development of evolutionary biology. Not only are the real achievements of the evolutionary synthesis in need of reevaluation, but this reassessment also has important implications for the historiography of Darwinism and the current debates about the darwinian movement.

The holism/reductionism debate in evolutionary biology has often been analysed as involving two main phenomenological levels within neo-Darwinism: genetic and organismic. This analytical framework assumes that explanation in evolution is either found in the field of genetics or the field of organismic biology. It is argued here that this framework is far too restrictive to incorporate what at least some founding members of neo-Darwinism had in mind in their search for the ultimate cause of evolution. Dobzhansky's "super-holism" locates this drive in the highest possible entity imaginable — an ontologically unified evolutionary cosmos — while Rensch's ontological "super-reductionism," on the other hand, places it at the lowest possible entity of microphysics, that is, at the level of an energetic field of protopsychical nature. Not only it is suggested that a much-expanded framework is required for analysing the holism/reductionism debate in neo-Darwinism, but also that this new framework may have implications for the conceptualization of the neo-Darwinian movement itself.

Contrairement à une croyance trop répandue, le darwinisme et son prolongement au XXe siècle — le néo-darwinisme — ne portent pas sur une idée de l'évolution fondée sur la simple notion de « la survie du plus apte ». Si la théorie de la sélection naturelle est partie intégrante du néo-darwinisme, plusieurs de ses fondateurs seront en quête d'une conception beaucoup plus généreuse, pleine et compréhensive de l'évolution. En réalité, la révolution dite darwinienne s'insère au coeur d'une révolution intellectuelle beaucoup plus importante : la révolution transformiste. Avant d'être des darwiniens, de dignes représentants de cette mouvance s'afficheront comme étant des transformistes. Cela signifie que, en plus des mécanismes de l'évolution biologique, d'autres éléments tout aussi cruciaux seront pris en considération`, dans l'élaboration d'une véritable synthèse évolutionniste : les rapports entre l'évolution biologique et l'évolution cosmique ; les interrogations portant sur la question d'une possible direction évolutive ; l'enseignement à tirer pour l'homme de sa place et de son rôle dans la nature. A la croisée de l'histoire, de la philosophie et de la science, cet ouvrage cherche à démontrer, à travers l'analyse des travaux de plusieurs néo-darwiniens de premier plan, que la révolution darwinienne demeurera incomplète aussi longtemps que la révolution transformiste le restera.

The Evolutionary Synthesis is often seen as a unification process in evolutionary biology, one which provided this research area with a solid common theoretical foundation. As such, neo-Darwinism is believed to constitute from this time onward a single, coherent, and unified movement offering research guidelines for investigations. While this may be true if evolutionary biology is solely understood as centred around evolutionary mechanisms, an entirely different picture emerges once other aspects of the founding neo-Darwinists’ views are taken into consideration, aspects potentially relevant to the elaboration of an evolutionary worldview: the tree of life, the ontological distinctions of the main cosmic entities , the inherent properties of self-organizing matter, evolutionary ethics, and so on. Profound tensions and inconsistencies are immediately revealed in the neo-Darwinian movement once this broader perspective is adopted. This pluralism is such that it is possible to identify at least three distinct and quasi-incommensurable epistemological/metaphysical frameworks as providing a proper foundation for neo-Darwinism. The analysis of the views of Theodosius Dobzhansky, Bernhard Rensch, and Ernst Mayr will illustrate this untenable pluralism, one which requires us to conceive of the neo-Darwinian research agenda as being conducted in more than one research programme or research tradition at the same time