This paper investigates whether it is fruitful to describe the role culture began to play at some point in the Hominin lineage as pointing to a transition in individuality, by reference to the works of Buss, Maynard-Smith and Szathmáry, Michod and Godfrey-Smith. The chief question addressed is whether a population of groups having different cultural phenotypes is either paradigmatically Darwinian or marginal, by using Godfrey-Smith's representation of such transitions in a multi-dimensional space. Richerson and Boyd's «dual inheritance» theory, and the (...) explanation it provides of the evolution of cooperation in the Hominin lineage, is taken into account to shed light on the way Godfrey-Smith deals with cultural evolution, especially concerning the amount of variation in a population of groups with various cultural phenotypes, the role played by multi-level selection in the evolutionary dynamics of such a population and the adequacy of different modalities of group- reproduction. (shrink)

The developmental properties of organisms play important roles in the generation of variation necessary for evolutionary change. But how can individual development steer the course of evolution? To answer this question, we introduce developmental channeling as a disposition of individual organisms that shapes their possible developmental trajectories and evolutionary dappling as an evolutionary outcome in which the space of possible organismic forms is dappled—it is only partially filled. We then trace out the implications of the channeling-dappling framework for contemporary debates (...) in the philosophy of evolution, including evolvability, reciprocal causation, and the extended evolutionary synthesis. (shrink)

The literature on the evolution of religion has been divided by a fundamental debate between adaptation theories, which explain religious traits as products of selection for religion, and byproduct theories, which explain religious traits as products of selection for other, non-religious functions. Recently, however, a new position has emerged in this debate, as an influential new theory based on cultural selection claims to integrate adaptation theories with byproduct theories, yielding a single, unified account. I argue that the proponents of this (...) view do not say enough about how integration is actually supposed to work, from a logical point of view. Basic questions arise from the assumptions required for unifying these apparently conflicting approaches, which the authors of the account do not address. In response to these questions, I provide a model of the religious phenotype, the Goldberg Exaptation Model, which shows that adaptation and byproduct theories are consistent, and explains how they are positively related, over and above mere consistency. On this view, the religious phenotype is best understood on analogy with a Rube Goldberg device: it is assembled by selection for religion, but using parts designed by selection for other, non-religious functions. (shrink)

The vast literature on negative treatment of outgroups and favoritism toward ingroups provides many local insights but is largely fragmented, lacking an overarching framework that might provide a unified overview and guide conceptual integration. As a result, it remains unclear where different local perspectives conflict, how they may reinforce one another, and where they leave gaps in our knowledge of the phenomena. Our aim is to start constructing a framework to help remedy this situation. We first identify a few key (...) ideas for creating a theoretical roadmap for this complex territory, namely the principles of etiological functionalism and the dual inheritance theory of human evolution. We show how a “molecular” approach to emotions fits into this picture, and use it to illuminate emotions that shape intergroup relations. Finally, we weave the pieces together into the beginnings of a systematic taxonomy of the emotions involved in social interactions, both hostile and friendly. While it is but a start, we have developed the argument in a way that illustrates how the foundational principles of our proposed framework can be extended to accommodate further cases. (shrink)

Darwin’s classic ‘Origin of Species’ (Darwin 1859) described forces of selection acting upon individuals, but there remains a great deal of controversy about what exactly the status and definition of a biological individual is. Recently some authors have argued that the individual is dispensable – that an inability to pin it down is not problematic because little rests on it anyway. The aim of this paper is to show that there is a real problem of biological individuality, and an urgent (...) need to arbitrate over the current plethora of solutions to it. (shrink)

The problem of plant individuality is something which has vexed botanists throughout the ages, with fashion swinging back and forth from treating plants as communities of individuals (Darwin 1800 ; Braun and Stone 1853 ; Münch 1938 ) to treating them as organisms in their own right, and although the latter view has dominated mainstream thought most recently (Harper 1977 ; Cook 1985 ; Ariew and Lewontin 2004 ), a lively debate conducted mostly in Scandinavian journals proves that the issues (...) are far from being resolved (Tuomi and Vuorisalo 1989b ; Fagerström 1992 ; Pan and Price 2001 ). In this paper I settle the matter once and for all, by showing which elements of each side are correct. (shrink)

Microbes are generally thought of as unicellular organisms, but we know that many microbes live as parts of biofilms—complex, surface-attached microbial communities numbering millions of cells. Some authors have recently argued in favour of reconceiving biofilms as biological entities in their own right. In particular, some have claimed that multispecies biofilms are evolutionary individuals : 10126–10132 2015). Against this view, I defend the conservative consensus that selection acts primarily upon microbial cells.

I analyze two recent parsimony arguments that have been offered to break the current impasse in the chimpanzee mindreading controversy, the ‘logical problem’ argument from Povinelli, Penn, and Vonk, and Sober's attempt to apply model selection criteria in support of the mindreading hypothesis. I argue that Sober's approach fails to adequately rebut the ‘logical problem’. However, applying model selection criteria to chimpanzees' own mental models of behavior does yield a response to the ‘logical problem’ and reveals an adaptive advantage of (...) mindreading models and a potential solution to a paradox raised by Whiten. (shrink)

What changes when an evolutionary transition in individuality takes place? Many different answers have been given, in respect of different cases of actual transition, but some have suggested a general answer: that a major transition is a change in the extent to which selection acts at one hierarchical level rather than another. The current paper evaluates some different ways to develop this general answer as a way to characterise the property ‘evolutionary individuality’; and offers a justification of the option taken (...) in Clarke :413–435, 2013)—to define evolutionary individuality in terms of an object’s capacity to undergo selection at its own level. In addition, I suggest a method by which the property can be measured and argue that a problem which is often considered to be fatal to that method—the problem of ‘cross-level by-products’—can be avoided. (shrink)

There is currently a great debate about whether the holobiont, i.e. a multicellular host and its residential microorganisms, constitutes a biological individual. We propose that resident microorganisms have a general and important role in the individuality of the host organism, not the holobiont. Drawing upon the Equilibrium Model of Immunity, we argue that microorganisms are scaffolds of immune capacities and processes that determine the constituency and persistence of the host organism. A scaffolding perspective accommodates the contingency and heterogeneity of resident (...) microorganisms while accounting for their necessity and unifying contributions to host individuality. In our symbiotic view of life, holobionts may not be organisms or units of selection, but macroorganisms cannot persist nor function as individuals without their scaffolding microorganisms. (shrink)

Cultural selection models aim to explain cultural phenomena as the products of a selective process, often characterising institutions, practices, norms or behaviours as adaptations. I argue that a lack of attention has been paid to the explanatory power of cultural selection frameworks. Arguments for cultural selection frequently depend on demonstrating only that selection models can in principle be applied to culture, rather than explicitly demonstrating the explanatory payoffs that could arise from their application. Understanding when and how cultural selection generates (...) powerful explanations is crucial to evaluating cultural selection, as well as realising its promised epistemic and practical benefits. I argue that the ability for cultural selection to explain ‘design without a designer’ is crucial to successful and powerful cultural selection explanations. I introduce the strategy of comparing cultural selection to goal-directed agent accounts in order to evaluate when cultural selection can provide distinctive explanatory payoffs, drawing on two case studies to illustrate the benefits of this strategy. I argue that a focus on phenomena which cannot be explained through intention or agency-based explanations in particular could provide a fruitful avenue to identifying the cases where cultural selection can be insightfully applied. (shrink)

High-fidelity cultural transmission, rather than brute intelligence, is the secret of our species’ success, or so many cultural evolutionists claim. It has been selected because it ensures the spread, stability and longevity of beneficial cultural traditions, and it supports cumulative cultural change. To play these roles, however, fidelity must be a causally-efficient property of cultural transmission. This is where the grain problem comes in and challenges the explanatory potency of fidelity. Assessing the degree of fidelity of any episode or mechanism (...) of cultural transmission always depends upon an investigator’s choice of grain of description at which cultural traditions are being studied. The fidelity of cultural transmission then appears to be relative to the granularity at which one approaches cultural variation, and since there is a multiplicity of grains of description by which the same tradition can be studied, there results a multiplicity of measures of fidelity for a same event or mechanism of cultural transmission. If this is correct, because fidelity is always relative to the grain of description dictated by the local and specific research interests of the investigator, then there seems to be no fact of the matter as to whether cultural transmission is faithful or not, independently from a researcher’s framework of analysis. The aims of this paper are to offer a conceptual clarification of the grain problem in cultural evolution, to assess its causes, to unpack its epistemological implications, and to examine its reach and consequences for a science of cultural evolution. (shrink)

La idea de herencia extendida se ha transformado en un leitmotiv de lo que se ha dado en llamar ‘síntesis extendida’. Dicha idea, entretanto, lleva a ignorar una de las marcas distintivas de lo que clásicamente se ha entendido por transmisión hereditaria: su estrecha asociación con el proceso de reproducción. Sin considerar tal asociación, la noción de herencia, más que ampliarse, de hecho se disuelve; y aceptar esa disolución acarrearía demasiadas dificultades para el discurso de las ciencias biológicas. Una de (...) esas dificultades tiene que ver con el concepto de variación hereditaria. Con la disolución de la noción de herencia, ese concepto también se disolvería; y, sin éste, la Teoría de la Selección Natural no puede articularse. Pero, no habiendo motivos valederos para aceptar semejante costo teórico, aquí quiero mostrar que ambos conceptos, el de herencia y el de variación hereditaria, pueden y deben ser elucidados sin aceptar la idea de herencia ampliada. (shrink)

The Central Dogma of molecular biology, which holds that DNA makes protein and not the other way around, is as influential as it is controversial. Some believe the Dogma has outlived its usefulness, either because it fails to fully capture the ins-and-outs of protein synthesis (Griffiths and Stotz, 2013; Stotz, 2006), because it turns on a confused notion of information (Sarkar, 2004), or because it problematically assumes the unidirectional flow of information from DNA to protein (Gottlieb, 2001). This paper evaluates (...) an underexplored defense of the Dogma, which relies on the assumption that the Dogma and the Inheritance of Acquired Traits, a principle which dates as far back as Jean Baptiste-Lamarck, are incompatible principles (Smith, 1993; Judson, 1979; Dawkins, 1970; Cobb, 2017; Wilkins, 2002; Graur, 2018). By appealing to empirical evidence in molecular science, I argue that this apparent incompatibility is indeed merely apparent. I conclude by briefly demonstrating how these considerations bear on the topic of conceptual pluralism in the philosophy of science (Stencel and Proszewska, 2018; Lu and Bourrat, 2018). (shrink)

This is the second of two articles in which I reflect on “generalized Darwinism” as currently discussed in evolutionary economics. In the companion article (Callebaut, Biol Theory 6. doi: 10.1007/s13752-013-0086-2, 2011, this issue) I approached evolutionary economics from the naturalistic perspectives of evolutionary epistemology and the philosophy of biology, contrasted evolutionary economists’ cautious generalizations of Darwinism with “imperialistic” proposals to unify the behavioral sciences, and discussed the continued resistance to biological ideas in the social sciences. Here I assess Generalized Darwinism (...) as propounded by Geoffrey Hodgson, Thorbjørn Knudsen, and others, concentrating on the roles of theory and model building in science (and the roles of analogy and metaphor therein), generative replication, and the relation between selection and self-organization. I then point to advances in current biology that promise to be more fruitful as sources of inspiration for evolutionary economics than the project to generalize Darwinism in its current, “hardened Modern Synthesis” form; and I draw some conclusions. (shrink)

To explain agent-identification behaviours, universalist theories in the biological and cognitive sciences have posited mental mechanisms thought to be universal to all humans, such as agent detection and face recognition mechanisms. These universalist theories have paid little attention to how particular sociocultural or historical contexts interact with the psychobiological processes of agent-identification. In contrast to universalist theories, contextualist theories appeal to particular historical and sociocultural contexts for explaining agent-identification. Contextualist theories tend to adopt idiographic methods aimed at recording the heterogeneity (...) of human behaviours across history, space, and cultures. Defenders of the universalist approach tend to criticise idiographic methods because such methods can lead to relativism or may lack generality. To overcome explanatory limitations of proposals that adopt either universalist or contextualist approaches in isolation, I propose a philosophical model that integrates contributions from both traditions: the psycho-historical theory of agent-identification. This theory investigates how the tracking processes that humans use for identifying agents interact with the unique socio-historical contexts that support agent-identification practices. In integrating hypotheses about the history of agents with psychological and epistemological principles regarding agent-identification, the theory can generate novel hypotheses regarding the distinction between recognition-based, heuristic-based, and explanation-based agent-identification. (shrink)

Cultural evolution is a growing, interdisciplinary, and disparate field of research. In ‘Cultural evolution: conceptual challenges”, Tim Lewens offers an ambitious analytical survey of this field that aims to clarify and defend its epistemic contributions, and highlight the limitations and risks associated with them. One overarching contention is that a form of population thinking dubbed the ‘kinetic approach’ should be seen as a unifying and justifying principle for cultural evolution, especially when considering the role of formal modelling. This book makes (...) a number of extremely valuable contributions to the literature. However, I argue that not all is as it may seem regarding the kinetic approach and that, while it does little to diminish the book’s value, the use which Lewens makes for it is problematic. (shrink)

This essay analyzes and develops recent views about explanation in biology. Philosophers of biology have parted with the received deductive-nomological model of scientific explanation primarily by attempting to capture actual biological theorizing and practice. This includes an endorsement of different kinds of explanation (e.g., mathematical and causal-mechanistic), a joint study of discovery and explanation, and an abandonment of models of theory reduction in favor of accounts of explanatory reduction. Of particular current interest are philosophical accounts of complex explanations that appeal (...) to different levels of organismal organization and use contributions from different biological disciplines. The essay lays out one model that views explanatory integration across different disciplines as being structured by scientific problems. I emphasize the philosophical need to take the explanatory aims pursued by different groups of scientists into account, as explanatory aims determine whether different explanations are competing or complementary and govern the dynamics of scientific practice, including interdisciplinary research. I distinguish different kinds of pluralism that philosophers have endorsed in the context of explanation in biology, and draw several implications for science education, especially the need to teach science as an interdisciplinary and dynamic practice guided by scientific problems and explanatory aims. (shrink)

Mereological nihilism is the thesis that composition never occurs. Some philosophers have thought that science gives us compelling evidence against nihilism. In this article I respond to this concern. An initial challenge for nihilism stems from the fact that composition is such a ubiquitous feature of scientific theories. In response I motivate a restricted form of scientific anti-realism with respect to those components of scientific theories which make reference to composition. A second scientifically based worry for nihilism is that certain (...) specific scientific phenomena might require ineliminable quantification over composite objects. I address these concerns, and argue that there seem to be nihilist-friendly construals of the scientific phenomena in question. (shrink)

Evolutionary transitions in individuality (ETIs) are events during which individuals at a given level of organization (particles) interact to form higher-level entities (collectives) which are then recognized as new individuals at that level. ETIs are intimately related to levels of selection, which, following Okasha, can be approached from two different perspectives. One, referred to as ‘synchronic’, asks whether selection occurs at the collective level while the partitioning of particles into collectives is taken for granted. The other, referred to as ‘diachronic’, (...) asks about the origins of the partitioning of particles into collectives. After having presented the two perspectives and a classical formalism used to deal with the levels-of-selection question in the literature, namely the multilevel version of the Price equation, I show that because this formalism treats the levels-of-selection question from a synchronic perspective, it is inadequate to explain ETIs. This is because a fundamental aspect of ETIs is the origin of collectives. From there, I develop a framework for levels of selection compatible with the diachronic perspective. This framework relies on the distinction between what I call, on the one hand, a ‘functional aggregative collective trait’, and on the other hand, a ‘functional non-aggregative collective trait’. After having presented this distinction, I implement it in the Price equation, leading to a new statistical partitioning of this equation which, I argue, represents a causal decomposition more relevant for ETIs. Finally, I exploit this partitioning to explain the critical stages of an ETI. In addition to its explanatory power, a measure of the degree of functional non-aggregativity could be used as a proxy for the degree of individuality of a collective. (shrink)

One of intuitions driving the acceptance of a neat structured tree of life is the assumption that organisms and the lineages they form have somewhat stable spatial and temporal boundaries. The phenomenon of symbiosis shows us that such ‘fixist’ assumptions does not correspond to how the natural world actually works. The implications of lateral gene transfer (LGT) have been discussed elsewhere; I wish to stress a related point. I will focus on lateral function transfer (LFT) and will argue, using examples (...) of what many would call ‘superorganisms’, that the emergence of symbiotic individuals revives the importance of functional and adaptationist thinking in how we conceptualize the lineages of biological individuals. The consequence of the argument is that, if we really want to hold onto tree of life thinking, we had better accept that new saplings appear and disappear all the time. (shrink)

In this paper I critically evaluate Reisman and Forber’s :1113–1123, 2005) arguments that drift and natural selection are population-level causes of evolution based on what they call the manipulation condition. Although I agree that this condition is an important step for identifying causes for evolutionary change, it is insufficient. Following Woodward, I argue that the invariance of a relationship is another crucial parameter to take into consideration for causal explanations. Starting from Reisman and Forber’s example on drift and after having (...) briefly presented the criterion of invariance, I show that once both the manipulation condition and the criterion of invariance are taken into account, drift, in this example, should better be understood as an individual-level rather than a population-level cause. Later, I concede that it is legitimate to interpret natural selection and drift as population-level causes when they rely on genuinely indeterministic events and some cases of frequency-dependent selection. (shrink)

We assess the arguments for recognising functionally integrated multispecies consortia as genuine biological individuals, including cases of so-called ‘holobionts’. We provide two examples in which the same core biochemical processes that sustain life are distributed across a consortium of individuals of different species. Although the same chemistry features in both examples, proponents of the holobiont as unit of evolution would recognize one of the two cases as a multispecies individual whilst they would consider the other as a compelling case of (...) ecological dependence between separate individuals. Some widely used arguments in support of the ‘holobiont’ concept apply equally to both cases, suggesting that those arguments have misidentified what is at stake when seeking to identify a new level of biological individuality. One important aspect of biological individuality is evolutionary individuality. In line with other work on the evolution of individuality, we show that our cases can be distinguished by focusing on the fitness alignment between the partners of the consortia. We conclude that much of the evidence currently presented for the ubiquity and importance of multi-species individuals is simply not to the point, at least unless the issue of biological individuality is firmly divorced from the question of evolutionary individuality. (shrink)

Yes, fitness is the central concept of evolutionary biology, but it is an elusive concept. Almost everyone who looks at it seriously comes out in a different place.

In this paper I argue against the claim, recently put forward by some philosophers of biology and evolutionary biologists, that there can be two or more ontologically distinct levels of selection. I show by comparing the fitness of individuals with that of collectives of individuals in the same environment and over the same period of time – as required to decide if one or more levels of selection is acting in a population – that the selection of collectives is a (...) by-product of selection at the individual level; thus, talking about two or more levels of selection represents merely a different perspective on one and the same process. (shrink)

ABSTRACTIn Darwinian Population and Natural Selection, Peter Godfrey-Smith brought the topic of natural selection back to the forefront of philosophy of biology, highlighting different issues surro...

There are two ways evolution by natural selection is conceptualized in the literature. One provides a ‘recipe’ for ENS incorporating three ingredients: variation, differences in fitness, and heritability. The other provides formal equations of evolutionary change and partitions out selection from other causes of evolutionary changes such as transmission biases or drift. When comparing the two approaches there seems to be a tension around the concept of heritability. A recent claim has been made that the recipe approach is flawed and (...) should be abandoned. In this article, I show that the tension is only a superficial one. If one uses a concept of heritability strictly in line with the formal equations of evolutionary change, the recipe approach keeps its validity and generality. To demonstrate that the intuitive concept of heritability is not a general one, I use one formulation of the Price equation formulated by Okasha, show that the concept of heritability in his formulation incorporates both the intuitive notion of heritability as a measure of similarity between parent and offspring characters, and a measure of persistence. I advocate for persistence to be incorporated in the concept of heritability used in recipes for ENS in the same way heredity is, show that this is readily attainable and thereby dissolve any point of tension concerning heritability between the recipe and the analytical approach to ENS. 1 Introduction2 Heritability in the Price Equation2.1 Different approaches to heredity and heritability2.2 Heritability: From recipes to the Price equation3 A Problem for the Recipes?4 Reinterpreting Heritability for Recipes5 Conclusion Appendix. (shrink)

Heritability is routinely interpreted causally. Yet, what such an interpretation amounts to is often unclear. Here, I provide a causal interpretation of this concept in terms of range of causal influence, one of several causal dimensions proposed within the interventionist account of causation. An information-theoretic measure of range of causal influence has recently been put forward in the literature. Starting from this formalization and relying upon Woodward’s analysis, I show that an important problem associated with interpreting heritability causally, namely the (...) locality problem, amounts, at least partly, to a low invariance and low stability between the genotype/environment and the phenotype of individuals. In light of this, I plead for a causal interpretation of heritability that takes the notions of Woodward’s invariance and stability into consideration. In doing so, I defuse naive causal interpretations of heritability. (shrink)

For evolution by natural selection to occur it is classically admitted that the three ingredients of variation, difference in fitness and heredity are necessary and sufficient. In this paper, I show using simple individual-based models, that evolution by natural selection can occur in populations of entities in which neither heredity nor reproduction are present. Furthermore, I demonstrate by complexifying these models that both reproduction and heredity are predictable Darwinian products (i.e. complex adaptations) of populations initially lacking these two properties but (...) in which new variation is introduced via mutations. Later on, I show that replicators are not necessary for evolution by natural selection, but rather the ultimate product of such processes of adaptation. Finally, I assess the value of these models in three relevant domains for Darwinian evolution. (shrink)

There is a tension between, on the one hand, the view that natural selection refers to individual-level causes, and on the other hand, the view that it refers to a population-level cause. In this article, I make the case for the individual-level cause view. I respond to recent claims made by McLoone that the individual-level cause view is inconsistent. I show that if one were to follow his arguments, any causal claim in any context would have to be regarded as (...) vindicating a form of population-level cause view. I show why this is implausible and how a consistent individual-level cause position can be held within the interventionist account of causation. Finally, I argue that there is one sense in which natural selection might be said to refer to population-level causes of evolutionary change. The upshot is that, as noted by others, natural selection can be regarded as referring to a population-level cause in the context of frequency-dependent selection and other situations of fitness-altering interactions between the individuals of a population. But whether this statement is true will depend on the empirical case investigated, not some a priori conceptual distinction. Thus, even though situations of frequency dependence might be ubiquitous, it is orthogonal to the conceptual question of whether frequency-independent natural selection—McLoone’s target—refers to individual- or population-level causes. (shrink)

Drift is often characterized in statistical terms. Yet such a purely statistical characterization is ambiguous for it can accept multiple physical interpretations. Because of this ambiguity it is important to distinguish what sorts of processes can lead to this statistical phenomenon. After presenting a physical interpretation of drift originating from the most popular interpretation of fitness, namely the propensity interpretation, I propose a different one starting from an analysis of the concept of drift made by Godfrey-Smith. Further on, I show (...) how my interpretation relates to previous attempts to make sense of the notion of expected value in deterministic setups. The upshot of my analysis is a physical conception of drift that is compatible with both a deterministic and indeterministic world. (shrink)

Building upon a non-standard understanding of evolutionary process focusing on variation and persistence, I will argue that communities and ecosystems can evolve by natural selection as emergent individuals. Evolutionary biology has relied ever increasingly on the modeling of population dynamics. Most have taken for granted that we all agree on what is a population. Recent work has reexamined this perceived consensus. I will argue that there are good reasons to restrict the term “population” to collections of monophyletically related replicators and (...) interactors, which explains why many existing models in population biology exclude by definition many genuine evolving biological individuals such as communities and ecosystems. By studying a case of community evolution, we will see that it is variation that is important to evolutionary processes, not populations. Variation within a population is only one of many types of variation that can lead to evolution by natural selection. The upshot of focusing on variation is that cases of community and ecosystem adaptive change become tractable in evolutionary terms. I will show that complex emergent individuals such as communities and ecosystems cannot be fully accommodated by conventional population/reproduction models but can be accommodated by variation/persistence models. (shrink)

Following Wallace’s suggestion, Darwin framed his theory using Spencer’s expression “survival of the fittest”. Since then, fitness occupies a significant place in the conventional understanding of Darwinism, even though the explicit meaning of the term ‘fitness’ is rarely stated. In this paper I examine some of the different roles that fitness has played in the development of the theory. Whereas the meaning of fitness was originally understood in ecological terms, it took a statistical turn in terms of reproductive success throughout (...) the 20th Century. This has lead to the ever-increasing importance of sexually reproducing organisms and the populations they compose in evolutionary explanations. I will argue that, moving forward, evolutionary theory should look back at its ecological roots in order to be more inclusive in the type of systems it examines. Many biological systems can only be satisfactorily accounted for by offering a non-reproductive account of fitness. This argument will be made by examining biological systems with very small or transient population structures. I argue this has significant consequences for how we define Darwinism, increasing the significance of survival over that of reproduction. (shrink)

Altruism is one of the most studied topics in theoretical evolutionary biology. The debate surrounding the evolution of altruism has generally focused on the conditions under which altruism can evolve and whether it is better explained by kin selection or multilevel selection. This debate has occupied the forefront of the stage and left behind a number of equally important questions. One of them, which is the subject of this article, is whether the word “selection” in “kin selection” and “multilevel selection” (...) necessarily refers to “evolution by natural selection.” I show, using a simple individual-centered model, that once clear conditions for natural selection and altruism are specified, one can distinguish two kinds of evolution of altruism, only one of which corresponds to the evolution of altruism by natural selection, the other resulting from other evolutionary processes. (shrink)

Extensive social choice theory is used to study the problem of measuring group fitness in a two-level biological hierarchy. Both fixed and variable group size are considered. Axioms are identified that imply that the group measure satisfies a form of consequentialism in which group fitness only depends on the viabilities and fecundities of the individuals at the lower level in the hierarchy. This kind of consequentialism can take account of the group fitness advantages of germ-soma specialization, which is not possible (...) with an alternative social choice framework proposed by Okasha, but which is an essential feature of the index of group fitness for a multicellular organism introduced by Michod, Viossat, Solari, Hurand, and Nedelcu to analyze the unicellular-multicellular evolutionary transition. The new framework is also used to analyze the fitness decoupling between levels that takes place during an evolutionary transition. (shrink)

A recent development in biology has been the growing acceptance that holobionts, entities comprised of symbiotic microbes and their host organisms, are widespread in nature. There is agreement that holobionts are evolved outcomes, but disagreement on how to characterize the operation of natural selection on them. The aim of this paper is to articulate the contours of the disagreement. I explain how two distinct foundational accounts of the process of natural selection give rise to competing views about evolutionary individuality.

This paper attempts to reconcile critics and defenders of inclusive fitness by constructing a synthesis that does justice to the insights of both. I argue that criticisms of the regression-based version of Hamilton’s rule, although they undermine its use for predictive purposes, do not undermine its use as an organizing framework for social evolution research. I argue that the assumptions underlying the concept of inclusive fitness, conceived as a causal property of an individual organism, are unlikely to be exactly true (...) in real populations, but they are approximately true given a specific type of weak selection that Hamilton took, on independent grounds, to be responsible for the cumulative assembly of complex adaptation. Finally, I reflect on the uses and limitations of “design thinking” in social evolution research. The debate about the foundations of inclusive fitness theory that has followed in the wake of Nowak, Tarnita and Wilson’s (1) critique has been remarkably polarizing. After several rounds of rebuttals and replies, there is still little evidence of any serious reconciliation between the theory’s critics (2-10) and its defenders (11-24). It doesn’t have to be this way. I believe that, on the main points of disagreement, it is possible to find a way forward that does justice to the insights of both camps. My aim in this paper is to find that way forward. (shrink)

Andrew Bourke’s Principles of Social Evolution identifies three stages that characterize an evolutionary transition in individuality and deploys inclusive fitness theory to explain each stage. The third stage, social group transformation, has hitherto received relatively little attention from inclusive fitness theorists. In this review, I first discuss Bourke’s “virtual dominance” hypothesis for the evolution of the germ line. I then contrast Bourke’s inclusive fitness approach to the major transitions with the multi-level approach developed by Richard Michod, Samir Okasha and others. (...) I suggest that, rather than choosing between these approaches, we should exploit the strengths of both. Finally, I stress the need for a firmer conceptual grasp of the nature of social group transformation. (shrink)

Various results show the ‘formal equivalence’ of kin and group selectionist methodologies, but this does not preclude there being a real and useful distinction between kin and group selection processes. I distinguish individual- and population-centred approaches to drawing such a distinction, and I proceed to develop the latter. On the account I advance, the differences between kin and group selection are differences of degree in the structural properties of populations. A spatial metaphor provides a useful framework for thinking about these (...) differences: kin and group selection may be conceptualized as large, overlapping regions of K - G space. I then consider some implications of the account, defend it from possible objections, and further argue that the structural features characteristic of both kin and group selection may recur at multiple levels of biological organization. (shrink)

I distinguish two roles for a fitness concept in the context of explaining cumulative adaptive evolution: fitness as a predictor of gene frequency change, and fitness as a criterion for phenotypic improvement. Critics of inclusive fitness argue, correctly, that it is not an ideal fitness concept for the purpose of predicting gene-frequency change, since it relies on assumptions about the causal structure of social interaction that are unlikely to be exactly true in real populations, and that hold as approximations only (...) given a specific type of weak selection. However, Hamilton took this type of weak selection, on independent grounds, to be responsible for cumulative assembly of complex adaptations. In this special context, I argue that inclusive fitness is distinctively valuable as a criterion for improvement and a standard for optimality. Yet to call inclusive fitness a criterion for improvement and a standard for optimality is not to make any claim about the frequency with which inclusive fitness optimization actually occurs in nature. This is an empirical question that cannot be settled by theory alone. I close with some reflections on the place of inclusive fitness in the long running clash between ‘causalist’ and ‘statisticalist’ conceptions of fitness. (shrink)

Inclusive fitness theory was not originally designed to explain the major transitions in evolution, but there is a growing consensus that it has the resources to do so. My aim in this paper is to highlight, in a constructive spirit, the puzzles and challenges that remain. I first consider the distinctive aspects of the cooperative interactions we see within the most complex social groups in nature: multicellular organisms and eusocial insect colonies. I then focus on one aspect in particular: the (...) extreme redundancy these societies exhibit. I argue that extreme redundancy poses a distinctive explanatory puzzle for inclusive fitness theory, and I offer a potential solution which casts coercion as the key enabler. I suggest that the general moral to draw from the case is one of guarded optimism: while inclusive fitness is a powerful tool for understanding evolutionary transitions, it must be integrated within a broader framework that recognizes the distinctive problems such transitions present and the distinctive mechanisms by which these problems may be overcome. (shrink)

This paper focuses on physiological integration in multicellular systems, a notion often associated with biological individuality, but which has not received enough attention and needs a thorough theoretical treatment. Broadly speaking, physiological integration consists in how different components come together into a cohesive unit in which they are dependent on one another for their existence and activity. This paper argues that physiological integration can be understood by considering how the components of a biological multicellular system are controlled and coordinated in (...) such a way that their activities can contribute to the maintenance of the system. The main implication of this perspective is that different ways of controlling their parts may give rise to multicellular organizations with different degrees of integration. After defining control, this paper analyses how control is realized in two examples of multicellular systems located at different ends of the spectrum of multicellularity: biofilms and animals. It focuses on differences in control ranges, and it argues that a high degree of integration implies control exerted at both medium and long ranges, and that insofar as biofilms lack long-range control (relative to their size) they can be considered as less integrated than other multicellular systems. It then discusses the implication of this account for the debate on physiological individuality and the idea that degrees of physiological integration imply degrees of individuality. (shrink)

The nature and status of cultural evolution and its connection with biological evolution are controversial in part because of Richard Dawkin’s suggestion that the scientific study of culture should include “memetics,” an analog of genetics in which genes are replaced by “memes”—the hypothetical units of cultural evolution. Memetics takes different forms; I focus on its minimal form, which claims merely that natural selection shapes to some extent the evolution of some aspects of culture. Advocates and critics of memetics disagree about (...) the scientific status of memetics, but they agree that memetics must face the following fundamental problems. Problem 1: Cultural evolution differs too much from biological evolution. Problem 2: Culture is too complex. Problem 3: Memes are too difficult to identify and track. Problem 4: Memetics produces only trivial results. This paper examines these problems in the context of a minimal memetic analysis in one specific context: patented inventions. Technology is a special subset of culture, and patented inventions are a special subset of technology—not least because there is a detailed written record of every patent. I describe four recent empirical results on technological innovation derived from memetic analysis of the patent record. Result 1: Inkjet printing, PCR, and stents are key drivers of technological innovation. Result 2: Patent genealogies are tangled and incestuous. Result 3: Door-opening innovations drive the evolution of technology. Result 4: The evolving content of the drivers of innovation confirms the importance of inkjet printing, PCR, and stents, among other inventions. These results show that minimal memetics can provide a novel and illuminating analysis the evolution of patented technology. Furthermore, this memetic analysis can answer all of the main problems with memetics. Problem 1 can be dismissed because culture and biology can be quite disanalogous, provided that natural selection still operates in both. Problem 2 is a mirage, because memetic analysis of the patented inventions is consistent with the full richness and complexity of the evolution of technology. Problem 3 is easy to solve, because the patent record makes it trivial to identify and track patents and their key traits through lineages. Problem 4 can be fully answered only after memetic analysis becomes widespread, but the results reviewed here shows that minimal memetics does yield scientific results that are nontrivial and interesting. (shrink)

Shapiro has suggested that the empirical plausibility of the multiple realizability of human-like minds is dubious, because a contrary thesis, the Mental Constraint Thesis, enjoys positive empirical evidence. The Mental Constraint Thesis states that, given the actual physical laws, there is only one way to realize a human-like mind. I will suggest, however, that the Mental Constraint Thesis is not a contrary to the empirical multiple realizability thesis relevant to psychological reduction or autonomy and, as a consequence, has no bearing (...) on those classificatory issues. (shrink)

This paper addresses the foundations of Teleological Individualism, the view that organisms, even non-sentient organisms, are goal-oriented systems while biological collectives, such as ecosystems or conspecific groups, are mere assemblages of organisms. Typical defenses of Teleological Individualism ground the teleological organization of organisms in the workings of natural selection. This paper shows that grounding teleological organization in natural selection is antithetical to Teleological Individualism because such views assume a view about the units of selection on which it is only individual (...) organisms that are units of selection. However, none of the Conventionalist, Reductionist, or Multi-Level Realist theories serve to justify such an assumption. Thus, Teleological Individualism cannot be grounded in natural selection. (shrink)

The Price equation is currently considered one of the fundamental equations —or even the fundamental equation— of evolution. In this article, we explore the role of this equation within cultural evolutionary theory. More specifically, we use it to account for the explanatory power and the theoretical structure of a certain generalised version of dual-inheritance theory. First, we argue that, in spite of not having a definite empirical content, the Price equation offers a suitable formalisation of the processes of cultural evolution, (...) and provides a powerful heuristic device for discovering the actual causes of cultural change and accumulation. Second, we argue that, as a consequence of this, a certain version of the Price equation is the fundamental law of cultural evolutionary theory. In order to support this claim, we sketch the ideal structure of dual-inheritance theory and we stress the unificatory role that the Price equation plays in it. (shrink)

Darwinian evolution is a population-level phenomenon. This paper deals with a structural population concept within the framework of generalized Darwinism, resp. within a generalized theory of evolution. According to some skeptical authors, GD is in need of a valid population concept in order to become a practicable research program. Populations are crucial and basic elements of any evolutionary explanation—biological or cultural—and have to be defined as clearly as possible. I suggest the “causal interactionist population concept”, by R. Millstein for this (...) purpose, and I will try to embed the approach into a generalized evolutionary perspective by mathematically formalizing its key definitions. Using graph-theory, populations as described in the CIPC can serve as proper clusters of evolutionary classification based on the rates of interactions between their elements. I will introduce the concept of a cohesion index as a measurement of possible population candidates within a distribution of elements. The strength of this approach lies in its applicability and interactions are relatively easy to observe. Furthermore, problems of clustering tokens via typicality, e.g. their similarity in intrinsic key characteristics, can be avoided, because CIPC is a external approach. However, some formal problems and conceptual ambiguities occur within a simple version of this CI, which will be addressed in this paper as well as some possible applications. (shrink)