Methodological and contextual factors in the Dawkins/Gould dispute over evolutionary progress

Biologists Richard Dawkins and Stephen Jay Gould have recently extended their decades-old disagreements about evolution to the issue of the nature and reality of evolutionary progress. According to Gould, ‘progress’ is a noxious notion that deserves to be expunged from evolutionary biology. In Dawkins' view, on the other hand, progress is one of the most important, pervasive and inevitable aspects of evolution. Simple appeals to ‘the evidence’ are clearly insufficient to resolve this disagreement, since it is precisely the interpretation of the evidence that is in dispute. Scientific controversies in general, and the Dawkins/Gould dispute over evolutionary progress in particular, are worth examining in some detail because doing so sheds light on the interconnected roles of methodological and contextual factors in the formation, articulation and defense of scientific claims. My aim in this paper is to clarify the structure of the Dawkins/Gould dispute by analyzing it in terms of a tri-level model of scientific controversies, involving ‘top-level’ substantive disagreements, ‘middle-level’ methodological differences, and ‘bottom-level’ differences in historical and social factors. This simple three-tiered model is sufficiently abstract to have more general applicability to other scientific controversies.     

Individuals and groups in evolution: Darwinian pluralism and the multilevel selection debate

Outlined here is an updated review of the long-standing ‘kin selection vs group selection’ debate. Group selection is a highly contentious concept, scientifically and philosophically. In 2012, Dawkins’ attack against Wilson’s latest book about eusociality concentrated all the attention on group selection and its mutual exclusivity with respect to inclusive fitness theory. Both opponents seem to be wrong, facing the general consensus in the field, which favours a pluralistic approach. Historically, despite some misunderstandings in current literature, such a perspective is clearly rooted in Darwin’s writings, which suggested a plurality of levels of selection and a general view that we propose to call ‘imperfect selfishness’. Today, the mathematically updated hypothesis of group selection has little to do with earlier versions of ‘group selection’. It does not imply ontologically unmanageable notions of ‘groups’. We propose here population structure as the main criterion of compatibility between kin selection and group selection. The latter is now evidently a pattern among others within a more general ‘multilevel selection’ theory. Different explanations and patterns are not mutually exclusive. Such a Darwinian pluralism is not a piece of the past, but a path into the future. A challenge in philosophy of biology will be to figure out the logical structure of this emerging pluralistic theory of evolution in such contentious debates.     

Gouldian arguments and the sources of contingency

‘Gouldian arguments’ appeal to the contingency of a scientific domain to establish that domain’s autonomy from some body of theory. For instance, pointing to evolutionary contingency, Stephen Jay Gould suggested that natural selection alone is insufficient to explain life on the macroevolutionary scale. In analysing contingency, philosophers have provided source-independent accounts, understanding how events and processes structure history without attending to the nature of those events and processes. But Gouldian Arguments require source-dependent notions of contingency. An account of contingency is source-dependent when it is indexed to (1) some pattern (i.e., microevolution or macroevolution) and (2) some process (i.e., Natural Selection, species sorting, etc.). Positions like Gould’s do not turn on the mere fact of life’s contingency—that life’s shape could have been different due to its sensitivity to initial conditions, path-dependence or stochasticity. Rather, Gouldian arguments require that the contingency is due to particular kinds of processes: in this case, those which microevolutionary theory cannot account for. This source-dependent perspective clarifies both debates about the nature and importance of contingency, and empirical routes for testing Gould’s thesis.     

Le dossier Vavilov

Vavilov’s dossier. Gould revived the memory of N.I. Vavilov, a victim of the Stalinian system and misjudged among occidental evolutionists. His contribution is impressive in applied research (phytogeography, his list of world-wide plant resources, a unique collection of germplasms intact and always available) as well as in theoretical research work on artificial selection, immunitary relationships between parasite and plant, the bases of his Law of homologous series in hereditary variations, and centers of origin of cultivated plants. Darwinian concept of natural selection were essential for him, but he considered that the evolutionary changes were not only produced by random variations, but by preset channels, recognising the internal constraints of heredity. His heritage has always been maintained in his Institutes. His Evolutionary theories are now confirmed by molecular genetics and systematics. S.J. Gould was the first to revive Vavilov’s memory and scientific importance. During his studies on the gastropod Cerion Gould recognised the balance between external and internal constraints in Evolution. To cite this article: M. Debrenne, F. Debrenne, C. R. Palevol 2 (2003).     

Gould on Laws in Biological Science

Are there laws in evolutionary biology? Stephen J. Gould has argued that there are factors unique to biological theorizing which prevent the formulation of laws in biology, in contradistinction to the case in physics and chemistry. Gould offers the problem of ’’complexity‘‘ as just such a fundamental barrier to biological laws in general, and to Dollo‘s Law in particular. But I argue that Gould fails to demonstrate: (1) that Dollo‘s Law is not law-like, (2) that the alleged failure of Dollo‘s Law demonstrates why there cannot be laws in biological science, and (3) that ’’complexity‘‘ is a fundamental barrier to nomologicality.     

Forget Evil: Autonomy,the Physician–Patient Relationship,and the Duty to Refer

Aulisio and Arora argue that the moral significance of value imposition explains the moral distinction between traditional conscientious objection and non-traditional conscientious objection. The former objects to directly performing actions, whereas the latter objects to indirectly assisting actions on the grounds that indirectly assisting makes the actor morally complicit. Examples of non-traditional conscientious objection include objections to the duty to refer. Typically, we expect physicians who object to a practice to refer, but the non-traditional conscientious objector physician refuses to refer. Aulisio and Arora argue that physicians have a duty to refer because refusing to do so violates the patient’s values. While we agree with Aulisio and Arora’s conclusions, we argue value imposition cannot adequately explain the moral difference between traditional conscientious objection and non-traditional conscientious objection. Treating autonomy as the freedom to live in accordance with one’s values, as Aulisio and Arora do, is a departure from traditional liberal conceptions of autonomy and consequently fails to explain the moral difference between the two kinds of objection. We outline how a traditional liberal understanding of autonomy would help in this regard, and we make two additional arguments—one that maintains that non-traditional conscientious objection undermines society’s autonomy, and another that maintains that it undermines the physician-patient relationship—to establish why physicians have a duty to refer.     

Selecting potential children and unconditional parental love

For now, the best way to select a child's genes is to select a potential child who has those genes, using genetic testing and either selective abortion, sperm and egg donors, or selecting embryos for implantation. Some people even wish to select against genes that are only mildly undesirable, or to select for superior genes. I call this selection drift – the standard for acceptable children is creeping upwards. The President's Council on Bioethics and others have raised the parental love objection : Just as we should love existing children unconditionally, so we should unconditionally accept whatever child we get in the natural course of things. If we set conditions on which child we get, we are setting conditions on our love for whatever child we get. Although this objection was prompted by selection drift, it also seems to cover selecting against genes for severe impairments.
I argue that selection drift is not inconsistent with the ideal of unconditional parental love and, moreover, that the latter actually implies that we should practise selection drift – in other words, we should try to select potential children with the best genetic endowments. My endowment argument for the second claim works from an analogy between arranging an endowment prior to conception to fund a future child's education, and arranging a genetic endowment by selecting a potential child who already has it, where in both cases the child would not have existed without the endowment. I conclude with some programmatic remarks about the nonidentity problem.     

A case reopened: teleology and its consequences for the units of selection discussion.

Darwinian explanations for teleology are often imprecise, and justify the occurrence of teleological features by referring to natural selection in a vague and unspecified sense. In this paper, the Darwinian account for teleology is further analyzed. It is argued that in theory only a specific form of teleology--teleology that is caused by and directed towards the preservation of the genetic program--can be explained in a naturalistic way by employing Darwin's theory of natural selection. This observation links teleology with the units of selection discussion, as for both discussions the end-direction of teleological processes and behavior is of elementary importance. According to Dawkins' analysis, the unit of selection is an active germ-like replicator with a sufficient degree of longevity-fecundity-copying fidelity. From the teleological point of view, the unit of selection should additionally incorporate the genetic program in order to naturalize teleology. It is shown that within sexually reproducing species these two requirements cannot be met. Dawkins' concept of genic selectionism cannot be maintained without violating the naturalistic claims on teleology, and none of the other frequently proposed unit of selection candidates can adequately meet the demands as developed by Dawkins and those developed in the light of teleology.     

It’s the song,not the singer: an exploration of holobiosis and evolutionary theory

That holobionts (microbial communities and their animal or plant hosts) are units of selection squares poorly with the observation that microbes are often recruited (horizontally acquired) from the environment, not passed down vertically from parent to offspring, as required for collective reproduction. The taxonomic makeup of a holobiont’s microbial community may vary over its lifetime and differ from that of conspecifics. In contrast, biochemical functions of the microbiota and contributions to host biology are more conserved, with taxonomically variable but functionally similar microbes recurring across generations and hosts. To save what is of interest in holobiont thinking, we propose casting metabolic and developmental interaction patterns, rather than the taxa responsible for them, as units of selection. Such units need not directly reproduce or form parent-offspring lineages: their prior existence has created the conditions under which taxa with the genes necessary to carry out their steps have evolved in large numbers. These taxa or genes will reconstruct the original interaction patterns when favorable conditions occur. Interaction patterns will vary (for instance by the alteration or addition of intermediates) in ways that affect the likelihood of and circumstances under which such reconstruction occurs. Thus, they vary in fitness, and evolution by natural selection will occur at this level. It is on the persistence, reconstruction, and spread of such interaction patterns that students of holobiosis should concentrate, we suggest. This model also addresses other multi-species collectively beneficial interactions, such as biofilms or biogeochemical cycles maintaining all life.     

What can natural selection explain?

One approach to assess the explanatory power of natural selection is to ask what type of facts it can explain. The standard list of explananda includes facts like trait frequencies or the survival of particular organisms. Here, I argue that this list is incomplete: natural selection can also explain a specific kind of individual-level fact that involves traits. The ability of selection to explain this sort of fact (‘trait facts’) vindicates the explanatory commitments of empirical studies on microevolution. Trait facts must be distinguished from a closely related kind of fact, that is, the fact that a particular individual x has one trait rather than another. Whether or not selection can explain the latter type of fact is highly controversial. According to the so-called ‘Negative View’ it cannot be explained by selection. I defend the Negative View against Nanay’s (2005) objection.     

Inclusive fitness and the sociobiology of the genome

Inclusive fitness theory provides conditions for the evolutionary success of a gene. These conditions ensure that the gene is selfish in the sense of Dawkins (The selfish gene, Oxford University Press, Oxford, 1976): genes do not and cannot sacrifice their own fitness on behalf of the reproductive population. Therefore, while natural selection explains the appearance of design in the living world (Dawkins in The blind watchmaker: why the evidence of evolution reveals a universe without design, W. W. Norton, New York, 1996), inclusive fitness theory does not explain how. Indeed, Hamilton’s rule is equally compatible with the evolutionary success of prosocial altruistic genes and antisocial predatory genes, whereas only the former, which account for the appearance of design, predominate in successful organisms. Inclusive fitness theory, however, permits a formulation of the central problem of sociobiology in a particularly poignant form: how do interactions among loci induce utterly selfish genes to collaborate, or to predispose their carriers to collaborate, in promoting the fitness of their carriers? Inclusive fitness theory, because it abstracts from synergistic interactions among loci, does not answer this question. Fitness-enhancing collaboration among loci in the genome of a reproductive population requires suppressing alleles that decrease, and promoting alleles that increase the fitness of its carriers. Suppression and promotion are effected by regulatory networks of genes, each of which is itself utterly selfish. This implies that genes, and a fortiori individuals in a social species, do not maximize inclusive fitness but rather interact strategically in complex ways. It is the task of sociobiology to model these complex interactions.     

The extended phenotype(s): a comparison with niche construction theory

While niche construction theory locates animal artefacts in their constructors’ environment, hence treating them as capable of exerting selective pressure on both the constructors and their descendants, the extended phenotype concept assimilates artefacts with their constructors’ genes. Analogous contrasts apply in the case of endoparasite and brood parasite genes influencing host behaviour. The explanatory power of these competing approaches are assessed by re-examining the core chapters of Richard Dawkins’ The Extended Phenotype. Because animal artefacts (chapter 11) have multiple evolutionary consequences for their constructors, the extra-body effects of a gene seemingly include feedback effects on multiple other genes, a result which is more consistent with niche construction theory than with selfish gene theory. In the case of endoparasite genes influencing host behaviour (chapter 12), Dawkins’ argument leaves out what appears to be the key explanatory component, namely the role of the host’s own bodily systems in making it possible for such genes to exist. For action at a distance (chapter 13), it is unclear whether the key genes have extended effects because they sit in the body of the manipulating organism, or alternatively do not have such effects because they sit in the body of its victim. It is argued that niche construction theory offers a superior explanation in all three cases, regardless of whether the extended phenotype concept is interpreted in selfish gene or selfish organism terms.     

Sexual selection and the evolution of exclusive paternal care in arthropods

Internal fertilization and anisogamy are thought to impede the evolution of exclusive paternal care by reducing paternity assurance and increasing male promiscuity. The potential role of sexual selection in easing these constraints is currently being examined in vertebrates but has not been seriously studied in most arthropods. To distinguish the effects of sexual from natural selection on the evolution of arthropod paternal care, I tested predictions of the state of several life history and behavioural traits under both forms of selection across all known taxa with exclusive paternal care. The results suggest parallels between prezygotic nuptial gifts and exclusive postzygotic paternal care and support the hypothesis that, in arthropods, male behaviours that enhance female reproductive success either directly by releasing females from the fecundity constraints of maternal care (enhanced fecundity hypothesis) or indirectly by identifying mates with superior genes (handicap principle) are traits on which sexual selection has acted. Under such conditions males willing to guard young become preferred mates for gravid females and enjoy greater promiscuity than males unable or unwilling to guard. Females use nest construction or the act of guarding another female's eggs as honest signals of paternal intent and quality. Copyright 2000 The Association for the Study of Animal Behaviour.     

Conscientious objection,professional duty and compromise: A response to Savulescu and Schuklenk

In a recent article in this journal, Savulescu and Schuklenk defend and extend their earlier arguments against a right to medical conscientious objection in response to criticisms raised by Cowley. I argue that while it would be preferable to be less accommodating of medical conscientious than many countries currently are, Savulescu and Schuklenk's argument that conscientious objection is ‘simply unprofessional’ is mistaken. The professional duties of doctors should be defined in relation to the interests of patients and society, and for reasons set out in this article, these may support limited accommodation of conscientious objection on condition that it does not impede access to services. Moreover, the fact that conscientious objection appears to involve unjustifiable compromise from the objector's point of view is not a reason for society not to offer that compromise. Arguing for robust enforcement of the no‐impediment condition, rather than opposing conscientious objection in principle, may be a more effective way of addressing the harms resulting from an over‐permissive conscientious objection policy.     

On Pluralism and Competition in Evolutionary Explanations

A controversy arose concerning the adaptive significance ofclitoral orgasm, disputing whether the presence of the traitin females is explained by appeal to developmental processesor natural selection (Gould, 1987a, b; Alcock, 1987). In response,Sherman (1988) offered a pluralistic solution in terms of levelsof analysis in which Gould and Alcock's disagreement was construedas semantic and not substantial. I argue that Sherman's solutionis mistaken. I suggest that the nature of the Gould/Alcock disputeis better understood by considering the abstract structure ofscientific theories and their role in explanation. This accountleads to a representation of science as having a plurality oftheoretical models which are integrated piecemeal in the explanationof concrete phenomena.     

Conscientious objection in healthcare: How much discretionary space best supports good medicine?

Daniel Sulmasy has recently argued that good medicine depends on physicians having a wide discretionary space in which they can act on their consciences. The only constraints Sulmasy believes we should place on physicians’ discretionary space are those defined by a form of tolerance he derives from Locke, whereby people can publicly act in accordance with their personal religious and moral beliefs as long as their actions are not destructive to society. Sulmasy also claims that those who would reject physicians’ right to conscientious objection eliminate discretionary space, thus undermining good medicine and unnecessarily limiting religious freedom. I argue that, although Sulmasy is correct that some discretionary space is necessary for good medicine, he is wrong in thinking that proscribing conscientious objection entails eliminating discretionary space. I illustrate this using Julian Savulescu and Udo Schuklenk’s system for restricting conscientious objections as a counter‐example. I then argue that a narrow discretionary space constrained by professional ideals will promote good medicine better than Sulmasy’s wider discretionary space constrained by his conception of tolerance. Sulmasy’s version of discretionary space would have us tolerate actions that are at odds with aspects of good medicine, including aspects that Sulmasy himself explicitly values, such as fiduciary duty. Therefore, if we want the degree of religious freedom in the public sphere that Sulmasy favours then we must decide whether it is worth the cost to the healthcare system.     

A defense of conscientious objection: Why health is integral to the permissibility of medical refusals

Schuklenk, Smalling, and Savulescu put forth four conditions that delineate when conscientious objection is impermissible. Roughly, they argue for the following claim: if some practice is legal, standard, expected of a profession, and in the patient's interest, then medical professionals cannot refuse to perform the practice. In this essay, I argue that these conditions are not jointly sufficient to deny medical professionals the ability to refuse to perform procedures that detract from a patient's health. They are insufficient to bar medical refusals to perform certain practices because, even when these conditions are met, non-health conducive practices would not be open to refusal by the physician. I provide an example of a non-health conducive practice female genital mutilation, which meets all of the proposed conditions but, intuitively, should be open to medical refusals. As a result, I conclude that the proposed conditions are insufficient to determine when conscientious objection is impermissible. I then offer an amendment to their position by suggesting that a practice, in addition to the other four conditions, must also be health conducive in order to remove the medical professional's ability to refuse to perform the practice.     

The consequences of direct versus indirect species interactions to selection on traits: pollination and nectar robbing in Ipomopsis aggregata

Organisms experience a complex suite of species interactions. Although the ecological consequences of direct versus indirect species interactions have received attention, their evolutionary implications are not well understood. I examined selection on floral traits through direct versus indirect pathways of species interactions using the plant Ipomopsis aggregata and its pollinators and nectar robber. Using path analysis and structural equation modeling, I tested competing hypotheses comparing the relative importance of direct (pollinator-mediated) versus indirect (robber-mediated) interactions to trait selection through female plant function in 2 years. The hypothesis that provided the best fit to the observed data included robbing and pollination, suggesting that both interactors are important in driving selection on some traits; however, the direction and intensity of selection through robbing versus pollination varied between years. I then increased my scope of inference by assessing traits and species interactions across more years. I found that the potential for temporal variation in the direction and intensity of selection was pronounced. Taken together, results suggest that assessing the broader context in which organisms evolve, including both direct and indirect interactions and across multiple years, can provide increased mechanistic understanding of the diversity of ways that animals shape floral and plant evolution.     

San Marco and evolutionary biology

Gould and Lewontin use San Marco, Venice, to criticise the adaptationist program in biology. Following their lead, the architectural term “spandrel” is now widely used in biology to denote a feature that is a necessary byproduct of other aspects of the organism. I review the debate over San Marco and argue that the spandrels are not necessary in the sense originally used by Gould and Lewontin. I conclude that almost all the claims that Gould makes about San Marco are wrong and that it is reasonable to view the architectural spandrel as an adaptation. The spandrels example has not provided a good illustration of why adaptive explanations should be avoided. In fact, it can be used as an example of how adaptive explanations can be dismissed even when there is evidence in their favour. I also discuss the use of the concept of a spandrel in biology.     

Urban evolutionary ecology brings exaptation back into focus

The contribution of pre-existing phenotypic variation to evolution in novel environments has long been appreciated. Nevertheless, evolutionary ecologists have struggled with communicating these aspects of the adaptive process. In 1982, Gould and Vrba proposed terminology to distinguish character states shaped via natural selection for the roles they currently serve (‘adaptations’) from those shaped under preceding selective regimes (‘exaptations’), with the intention of replacing the inaccurate ‘preadaptation’. Forty years later, we revisit Gould and Vrba’s ideas which, while often controversial, continue to be widely debated and highly cited. We use the recent emergence of urban evolutionary ecology as a timely opportunity to reintroduce the ideas of Gould and Vrba as an integrated framework to understand contemporary evolution in novel environments.