Frédéric Bouchard

Functional diversity holds the promise of understanding ecosystems in ways unattainable by taxonomic diversity studies. Underlying this promise is the intuition that investigating the diversity of what organisms actually do—i.e. their functional traits—within ecosystems will generate more reliable insights into the ways these ecosystems behave, compared to considering only species diversity. But this promise also rests on several conceptual and methodological—i.e. epistemic—assumptions that cut across various theories and domains of ecology. These assumptions should be clearly addressed, notably for the sake of an effective comparison and integration across domains, and for assessing whether or not to use functional diversity approaches for developing ecological management strategies. The objective of this contribution is to identify and critically analyze the most salient of these assumptions. To this aim, we provide an “epistemic roadmap” that pinpoints these assumptions along a set of historical, conceptual, empirical, theoretical, and normative dimensions.

We argue that a fashionable interpretation of the theory of natural selection as a claim exclusively about populations is mistaken. The interpretation rests on adopting an analysis of fitness as a probabilistic propensity which cannot be substantiated, draws parallels with thermodynamics which are without foundations, and fails to do justice to the fundamental distinction between drift and selection. This distinction requires a notion of fitness as a pairwise comparison between individuals taken two at a time, and so vitiates the interpretation of the theory as one about populations exclusively.

Philosophers of biology have been absorbed by the problem of defining evolutionary fitness since Darwin made it central to biological explanation. The apparent problem is obvious. Define fitness as some biologists implicitly do, in terms of actual survival and reproduction, and the principle of natural selection turns into an empty tautology: those organisms which survive and reproduce in larger numbers, survive and reproduce in larger numbers. Accordingly, many writers have sought to provide a definition for ‘fitness’ which avoid this outcome. In particular the definition of fitness as a probabilistic propensity has been widely favored.1 Others, recognizing that no definition both correct and complete can actually be provided, have accepted the consequence that the leading principle of the theory is a definitional truth and attempted to mitigate the impact of this outcome for the empirical character of the theory.2 Still others have argued that ‘fitness’ is properly viewed as a term undefined in the theory of natural selection (on the model of mass—a term undefined in Newtonian mechanics).3 But few have contemplated the solution to this problem proposed by Mohan Matthen and André Ariew (hereafter, MA), in..

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

Ecological fitness has been suggested to provide a unifying definition of fitness. However, a metric for this notion of fitness was in most cases unavailable except by proxy with differential reproductive success. In this article, I show how differential persistence of lineages can be used as a way to assess ecological fitness. This view is inspired by a better understanding of the evolution of some clonal plants, colonial organisms, and ecosystems. Differential persistence shows the limitation of an ensemblist noncausal understanding of evolution. Causal explanations are necessary to understand the evolution by natural selection of these biological systems. †To contact the author write to: Department of Philosophy, University of Montreal, P.O. Box 6128, Station Centre‐Ville, Montreal, Quebec, H3C 3J7 Canada; e‐mail: [email protected].

Given the complexity of most phenomena, we have to delegate much epistemic work to other knowers and we must find reasons for relying on these specific knowers and not others. In our societies, these other knowers are often called experts and we rely on their epistemic authority more and more. For many complex phenomena such as climate change, genetically modified crops, and immunization, the experts that are called upon are scientific experts. For that reason, finding good reasons and justification for deferring to their knowledge is of paramount societal importance. As we shall see, many have analyzed this epistemic dependence on scientific experts and have tried to show in what contexts are there good...

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 (a symbiotic termite–fungus community), 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.

We argue that ecology in general and biodiversity and ecosystem function research in particular need an understanding of functions which is both ahistorical and evolutionarily grounded. A natural candidate in this context is Bigelow and Pargetter’s evolutionary forward-looking account which, like the causal role account, assigns functions to parts of integrated systems regardless of their past history, but supplements this with an evolutionary dimension that relates functions to their bearers’ ability to thrive and perpetuate themselves. While Bigelow and Pargetter’s account focused on functional organization at the level of organisms, we argue that such an account can be extended to functional organization at the community and ecosystem levels in a way that broadens the scope of the reconciliation between ecosystem ecology and evolutionary biology envisioned by many BEF researchers. By linking an evolutionary forward-looking account of functions to the persistence-based understanding of evolution defended by Bouchard and others, and to the theoretical research on complex adaptive systems, we argue that ecosystems, by forming more or less resilient assemblages, can evolve even while they do not reproduce and form lineages. We thus propose a Persistence Enhancing Propensity account of role functions in ecology to account for this overlap of evolutionary and ecological processes

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.

E. O. Wilson (1974: 54) describes the problem that social organisms pose: “On what bases do we distinguish the extremely modified members of an invertebrate colony from the organs of a metazoan animal?” This framing of the issue has inspired many to look more closely at how groups of organisms form and behave as emergent individuals. The possible existence of “superorganisms” test our best intuitions about what can count and act as genuine biological individuals and how we should study them. As we will discuss, colonies of certain organisms display many of the properties that we usually reserve only to individual organisms. Although there is good reason to believe that many social insects form genuine emergent biological individuals, the conclusion offered here is of a slightly different sort. I will argue that to understand some social insects' interactions and the emergent traits they give rise to, it may be helpful to shift our understanding from a community-level approach to an ecosystem-level approach. I will argue that viewing certain insect colonies (termites) as parts of ecosystems allows us to better understand some of the adaptations that have emerged from their evolution.

Our intuitive assumption that only organisms are the real individuals in the natural world is at odds with developments in cell biology, ecology, genetics, evolutionary biology, and other fields. Although organisms have served for centuries as nature’s paradigmatic individuals, science suggests that organisms are only one of the many ways in which the natural world could be organized. When living beings work together—as in ant colonies, beehives, and bacteria-metazoan symbiosis—new collective individuals can emerge. In this book, leading scholars consider the biological and philosophical implications of the emergence of these new collective individuals from associations of living beings. The topics they consider range from metaphysical issues to biological research on natural selection, sociobiology, and symbiosis. The contributors investigate individuality and its relationship to evolution and the specific concept of organism; the tension between group evolution and individual adaptation; and the structure of collective individuals and the extent to which they can be defined by the same concept of individuality. These new perspectives on evolved individuality should trigger important revisions to both philosophical and biological conceptions of the individual. Contributors: Frédéric Bouchard, Ellen Clarke, Jennifer Fewell, Andrew Gardner, Peter Godfrey-Smith, Charles J. Goodnight, Matt Haber, Andrew Hamilton, Philippe Huneman, Samir Okasha, Thomas Pradeu, Scott Turner, Minus van Baalen

La philosophie de la biologie est un domaine extrêmement actif de la recherche dans la tradition philosophique anglo-saxonne. Elle réunit philosophes et biologistes autour de la question de la définition des concepts fondamentaux : gène, cellule, organisme, espèce, développement, évolution, adaptation, etc. Ce livre, qui rassemble les contributions d’une trentaine de spécialistes français et étrangers, présente en 24 chapitres l’état de la recherche actuelle dans tous les principaux domaines de la biologie. Il peut être utilisé comme manuel pour les cours de philosophie des sciences au niveau Master.

Our intuitive assumption that only organisms are the real individuals in the natural world is at odds with developments in cell biology, ecology, genetics, evolutionary biology, and other fields. Although organisms have served for centuries as nature's paradigmatic individuals, science suggests that organisms are only one of the many ways in which the natural world could be organized. When living beings work together--as in ant colonies, beehives, and bacteria-metazoan symbiosis--new collective individuals can emerge. In this book, leading scholars consider the biological and philosophical implications of the emergence of these new collective individuals from associations of living beings. The topics they consider range from metaphysical issues to biological research on natural selection, sociobiology, and symbiosis.