Biological individuality is a notoriously thorny topic for biologists and philosophers of biology. In this paper we argue that biological individuality presents multiple, interconnected questions for biologists and philosophers that together form a problem agenda. Using a case study of an interdisciplinary research group in ecology, behavioral and evolutionary biology, we claim that a debate on biological individuality that seeks to account for diverse practices in the biological sciences should be broadened to include and give prominence to questions about uniqueness (...) and temporality. We show that broadening the problem agenda of biological individuality draws attention to underrecognized philosophical issues and discussions and thereby organizes and enriches the existing debate. (shrink)

Bourrat and Griffiths :33, 2018) have recently argued that most of the evidence presented by holobiont defenders to support the thesis that holobionts are evolutionary individuals is not to the point and is not even adequate to discriminate multispecies evolutionary individuals from other multispecies assemblages that would not be considered evolutionary individuals by most holobiont defenders. They further argue that an adequate criterion to distinguish the two categories is fitness alignment, presenting the notion of fitness boundedness as a criterion that (...) allows divorcing true multispecies evolutionary individuals from other multispecies assemblages and provides an adequate criterion to single out genuine evolutionary multispecies assemblages. A consequence of their criterion is that holobionts, as conventionally defined by hologenome defenders, are not evolutionary individuals except in very rare cases, and for very specific host-symbiont associations. This paper is a critical response to Bourrat and Griffiths’ arguments and a defence of the arguments presented by holobiont defenders. Drawing upon the case of the hologenomic basis of the evolution of sanguivory in vampire bats, I argue that Bourrat and Griffiths overlook some aspects of the biological nature of the microbiome that justifies the thesis that holobionts are evolutionarily different to other multispecies assemblages. I argue that the hologenome theory of evolution should not define the hologenome as a collection of genomes, but as the sum of the host genome plus some traits of the microbiome which together constitute an evolutionary individual, a conception I refer to as the stability of traits conception of the hologenome. Based on that conception I argue that the evidence presented by holobiont defenders is to the point, and supports the thesis that holobionts are evolutionary individuals. In this sense, the paper offers an account of the holobiont that aims to foster a dialogue between hologenome advocates and hologenome critics. (shrink)

Both Aristotle and Ernst Mayr present theories of dual explanation in biology, with proximal, clearly physical explanations and more distal, biology-specific explanations. Aristotle’s presentation of final cause explanations in Posterior Analytics relates final causes to the necessary material, formal, and efficient causes that mediate them. Johnson and Leunissen demonstrate the problematic nature of historical and recent interpretations and open the door for a new interpretation consistent with modern evolutionary theory. Mayr’s differentiation of proximate and ultimate/evolutionary causes provides a key to (...) appropriating Aristotle for modern use, if care is taken to differentiate Mayr’s proximate/distal and mechanical/evolutionary distinctions from his intentional/non-intentional distinction. Building on Mayr, and noting his appropriation of ancient and recent commentary, a strong case can be made for nested explanation, wherein evolutionary explanations are instantiated in systems of mechanical explanations. Biological concepts of organism, gene, function, etc., are etiologically prior to mechanical explanations of function, but temporally posterior to mechanical explanations of historical adaptation. Such an analysis sheds light on recent arguments within evolutionary biology while highlighting the importance of epistemology in contemporary science. (shrink)

Biological individuals are usually defined by evolutionists through a reference to natural selection. This article looks for a concept of individuality that would hold at the same time for organisms and for communities or ecosystems, the latter being unaffected by natural selection. In the wake of Simon’s notion of “quasi-independence,” I elaborate a concept of “weak individuality” defined by probabilistic connections between sub-entities, read off our knowledge of their interactions. This formal scheme of connections allows one to infer what are (...) the individuals in the domain addressed by the theory of the interactions. The article argues that if ecosystems do not have strong individuality, they still possess a weak individuality, ecological theories providing the values of the variables in the formula for individuality. (shrink)

Canguilhem criticized the concept of “public health”: health and disease are concepts that only apply to individuals, taken as organic totalities. Their extension to a different level of organization is purely metaphorical. The importance assumed by epidemiology in the construction of our knowledge of the normal and the pathological does, however, call for reflection on the role and the status of the population level of organization in our approach to health phenomena. The entanglement of the biological and the social in (...) human life and in contemporary societies justifies this level of analysis for better understanding the complexity and the interaction of health determinants both at the level of individuals and their interactions and at that of the population. But is this population level just a useful level of analysis that makes it possible to bring to light the social determinants of health at the individual level, or does it rest instead on characteristics of the population that are irreducible to individual characteristics, but which are nevertheless important for understanding and taking action with respect to both population and individual health? Defending this second alternative, I show how the epidemiological point of view, and in particular that of social epidemiology, leads us to rethink the possibility of a concept of “population health” that is not reducible to the sum of individual instances of health. (shrink)

Given immunity’s general role in the organism’s economy—both in terms of its internal environment as well as mediating its external relations—immune theory has expanded its traditional formulation of preserving individual autonomy to one that includes accounting for nutritional processes and symbiotic relationships that require immune tolerance. When such a full ecological alignment is adopted, the immune system becomes the mediator of both defensive and assimilative environmental intercourse, where a balance of immune rejection and tolerance governs the complex interactions of the (...) organism’s ecological relationships. Accordingly, immunology, which historically had affiliated with the biology of individuals, now becomes a science concerned with the biology of communities. With this translocation, the ontological basis of the organism is undergoing a profound change. Indeed, the recent recognition of the ubiquity of symbiosis has challenged the traditional notions of biological individuality and requires a shift in the metaphysics undergirding biology, in which a philosophy of the organism must be characterized by ecological dialectics “all-the-way-down.”. (shrink)

The Darwinian theory of evolution is itself evolving and this book presents the details of the core of modern Darwinism and its latest developmental directions. The authors present current scientific work addressing theoretical problems and challenges in four sections, beginning with the concepts of evolution theory, its processes of variation, heredity, selection, adaptation and function, and its patterns of character, species, descent and life. The second part of this book scrutinizes Darwinism in the philosophy of science and its usefulness in (...) understanding ecosystems, whilst the third section deals with its application in disciplines beyond the biological sciences, including evolutionary psychology and evolutionary economics, Darwinian morality and phylolinguistics. The final section addresses anti-Darwinism, the creationist view and issues around teaching evolution in secondary schools. The reader learns how current experimental biology is opening important perspectives on the sources of variation, and thus of the very power of natural selection. This work examines numerous examples of the extension of the principle of natural selection and provides the opportunity to critically reflect on a rich theory, on the methodological rigour that presides in its extensions and exportations, and on the necessity to measure its advantages and also its limits. Scholars interested in modern Darwinism and scientific research, its concepts, research programs and controversies will find this book an excellent read, and those considering how Darwinism might evolve, how it can apply to the human sciences and other disciplines beyond its origins will find it particularly valuable. Originally produced in French (Les Mondes Darwiniens), the scope and usefulness of the book have led to the production of this English text, to reach a wider audience. This book is a milestone in the impressive penetration by Francophone scholars into the world of Darwinian science, its historiography and philosophy over the last two decades. Alex Rosenberg, R. Taylor Cole Professor of Philosophy, Duke University Until now this useful and comprehensive handbook has only been available to francophones. Thanks to this invaluable new translation, this collection of insightful and original essays can reach the global audience it deserves. Tim Lewens, University of Cambridge. (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)