Ethnobiology has a long tradition of metaphysical debates about the “naturalness,” “objectivity”, “reality”, and “universality” of classifications. Especially the work of Brent Berlin has been influential in developing a “convergence metaphysics” that explains cross-cultural similarities of knowledge systems through shared recognition of objective discontinuities in nature. Despite its influence on the development of the field, convergence metaphysics has largely fallen out of favor as contemporary ethnobiologists tend to emphasize the locality and diversity of classificatory practices. The aim of this article (...) is twofold: First, I provide a historical account of the rise and fall of convergence metaphysics in ethnobiology. I show how convergence metaphysics emerged as an innovative theoretical program in the wake of the “cognitive revolution” and the “modern evolutionary synthesis” but failed to incorporate both theoretical insights and political concerns that gained prominence in the 1980s and 1990s. Second, I develop a positive proposal of how to engage with metaphysical issues in ethnobiology. By integrating traditional research on convergence of classifications with more nuanced accounts of distinctly local categories, a revamped metaphysics of ethnobiological classification can make substantial contributions to debates about ontological difference in anthropology and about the relation between applied and theoretical ethnobiology. (shrink)

In this paper, we discuss the following four alternative ways of understanding the outcomes of resurrection biology. Implications of each of the ways are discussed with respect to concepts of species and extinction. Replication: animals created by resurrection biology do not belong to the original species but are copies of it. The view is compatible with finality of extinction as well as with certain biological and ecological species concepts. Re-creation: animals created are members of the original species but, despite their (...) existence, the species remains extinct. The view is incompatible with all species concepts presented. Non-extinction: animals produced belong to the original species which actually never went extinct. The view may be consistent with phenetic and phylogenetic species concepts as well as with finality of extinction. According to literal resurrection, resurrection biology is successful in reversing extinction through the creation of new members of species that once went extinct. This view presupposes non-finality of extinction and it is compatible with phenetic species concepts. It is notable that no species or extinction concept is consistent with all possible views of resurrection biology nor is any view of resurrection biology consistent with all species or extinction concepts. Thus, one’s views regarding species and extinction determine which views one can adopt regarding resurrection biology and vice versa. (shrink)

The vast majority of biological taxonomists use the Linnaean system when constructing classifications. Taxa are assigned Linnaean ranks and taxon names are devised according to the Linnaean rules of nomenclature. Unfortunately, the Linnaean system has become theoretically outdated. Moreover, its continued use causes a number of practical problems. This paper begins by sketching the ontological and practical problems facing the Linnaean system. Those problems are sufficiently pressing that alternative systems of classification should be investigated. A number of proposals for an (...) alternative system are introduced and evaluated. The best aspects of those proposals are brought together to form a post-Linnaean system, and a comparison of the Linnaean and post-Linnaean systems is conducted. The final section of this paper considers not only the theoretical reasons for replacing the Linnaean system, but also the practical feasibility of adopting an alternative system. (shrink)

At least 22 concepts of species are in use today and many of these are notably incompatible in their accounts of biological diversity. Much of the traditional turmoil embodied in the species problem ultimately derives from the packaging of inappropriate criteria for species into a single concept. This results from a traditional conflation of function of concepts with their applications, definitions with concepts, taxonomic categories with groups, and the ontological status of real species with teleological approaches to recover them. Analogous (...) to classifications of supraspecific taxa, our forging inappropriate and ambiguous information relating to theoretical and operational discussions of species ultimately results in a trade-off between convenience, accuracy, precision, and the successful recovery of natural biological diversity. Hence, none of these expectations or intentions of species or classifications is attainable through composite, and possibly discordant, concepts of biological diversity or its descent. Reviewing and evaluating the concepts of species for their theoretical and operational qualities illustrates that a monistic, primary concept of species, applicable to the various entities believed to be species, is essential. This evaluation reveals only one theoretical concept as appropriate for species, the Evolutionary Species Concept. This conceptualization functions as a primary concept and is essential in structuring our ideas and perceptions of real species in the natural world. The remaining concepts are secondary, forming a hierarchy of definitional guidelines subordinate to the primary concept, and are essential to the study of species in practice. Secondary concepts should be used as operational tools, where appropriate, across the variance in natural diversity to discover entities in accord with the primary concept. Without this theoretical and empirical structuring of concepts of species our mission to achieve reconciliation and understanding of pattern and process of the natural world will fail. (shrink)

At least three different issues are commonly referred to by the term “the species problem”: one concerns the necessary properties of species, a second the processes responsible for the existence of species, and a third methods for inferring species limits. Solutions have recently been proposed to the first two problems, which are conceptual in nature (the third is methodological). The first equates species with metapopulation lineages and proposes that existence as a separately evolving metapopulation lineage be considered the only necessary (...) property of species. The second views the species category as a cluster concept and proposes that no single process or set of processes be considered necessary for the existence of species. Although these two solutions have been portrayed as being in conflict, they are, in fact, highly compatible. Moreover, the proposals in question clarify the problem concerning methods for inferring the limits of species, which has for a long time been confused with the problem concerning the necessary properties of species. Together these proposals provide the opportunity for biology to move beyond debates about the definition of the species category and focus on estimating the boundaries and numbers of species as well as studying the diverse processes involved in their origin and persistence. BioEssays 27:1263–1269, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

This paper is a critical discussion of John Dupré's recent defence of promiscuous realism in Part 1 of his The Disorder of Things: Metaphysical Foundations of the Disunity of Science. It also discusses some more general issues in the philosophy of biology and science. Dupré's chief strategy of argumentation appeals to debates within the philosophy of biology, all of which concern the nature of species. While the strategy is well motivated, I argue that Dupré's challenge to essentialist and unificationist views (...) about natural kinds is not successful. One conclusion is that an integrative conception of species is a real alternative to Dupré's pluralism. (shrink)

This paper examines the species problem in microbiology and its implications for the species problem more generally. Given the different meanings of ‘species’ in microbiology, the use of ‘species’ in biology is more multifarious and problematic than commonly recognized. So much so, that recent work in microbial systematics casts doubt on the existence of a prokaryote species category in nature. It also casts doubt on the existence of a general species category for all of life (one that includes both prokaryotes (...) and eukaryotes). Prokaryote biology also undermines recent attempts to save the species category, such as the suggestion that species are metapopulation lineages and the idea that ‘species’ is a family resemblance concept. (shrink)

Biologists and philosophers that debate the existence of the species category fall into two camps. Some believe that the species category does not exist and the term 'species' should be eliminated from biology. Others believe that with new biological insights or the application of philosophical ideas, we can be confident that the species category exists. This paper offers a different approach to the species problem. We should be skeptical of the species category, but not skeptical of the existence of those (...) taxa biologists call 'species.' And despite skepticism over the species category, there are pragmatic reasons for keeping the word 'species.' This approach to the species problem is not new. Darwin employed a similar strategy to the species problem 150 years ago. (shrink)

The biological species (biospecies) concept applies only to sexually reproducing species, which means that until sexual reproduction evolved, there were no biospecies. On the universal tree of life, biospecies concepts therefore apply only to a relatively small number of clades, notably plants andanimals. I argue that it is useful to treat the various ways of being a species (species modes) as traits of clades. By extension from biospecies to the other concepts intended to capture the natural realities of what keeps (...) taxa distinct, we can treat other modes as traits also, and so come to understand that theplurality of species concepts reflects the biological realities of monophyletic groups.We should expect that specialists in different organisms will tend to favour those concepts that best represent the intrinsic mechanisms that keep taxa distinct in their clades. I will address the question whether modes ofreproduction such as asexual and sexual reproduction are natural classes, given that they are paraphyletic in most clades. (shrink)

Gayon's recent claim that Buffon developed a concept of species as physical individuals is critically examined and rejected. Also critically examined and rejected is Gayon's more central thesis that as a consequence of his analysis of Buffon's species concept, and also of Darwin's species concept, it is clear that modern evolutionary theory does not require species to be physical individuals. While I agree with Gayon's conclusion that modern evolutionary theory does not require species to be physical individuals, I disagree with (...) his reasons and instead provide logical rather than historical reasons for the same conclusion. (shrink)

The correct explanation of why species, in evolutionary theory, are individuals and not classes is the cladistic species concept. The cladistic species concept defines species as the group of organisms between two speciation events, or between one speciation event and one extinction event, or (for living species) that are descended from a speciation event. It is a theoretical concept, and therefore has the virtue of distinguishing clearly the theoretical nature of species from the practical criteria by which species may be (...) recognized at any one time. Ecological or biological (reproductive) criteria may help in the practical recognition of species. Ecological and biological species concepts are also needed to explain why cladistic species exist as distinct lineages, and to explain what exactly takes place during a speciation event. The ecological and biological species concepts work only as sub-theories of the cladistic species concept and if taken by themselves independently of cladism they are liable to blunder. The biological species concept neither provides a better explanation of species indivudualism than the ecological species concept, nor, taken by itself, can the biological species concept even be reconciled with species individualism. Taking the individuality of species seriously requires subordinating the biological, to the cladistic, species concept. (shrink)

Since the 1970s, there has been a tremendous amount of literature on Ghiselin's proposal that species are individuals. After recalling the origins and stakes of this thesis in contemporary evolutionary theory, I show that it can also be found in the writings of the French naturalist Buffon in the 18th Century. Although Buffon did not have the conception that one species could be derived from another, there is an interesting similarity between the modern argument and that of Buffon regarding the (...) individuality of species. The analogy is strong enough to force us to recognize that genuine evolutionary (or Darwinian) questions might be of secondary importance in the discussion. In consequence, the third section of the paper proposes an alternative schema for the logical structure of the Darwinian concept of species. Darwin distinguished the problem of the designation of a concrete species, and the problem of its signification of species within his theory of descent? The resulting notion of species involves a logical structure based on the fusion of the logical operations of classification and ordering. The difficulty — and interest — is that this interpretation of species does not entail any precise operational definition of species; it can only tell us what the ultimate signification of classification is within the theory of descent with modification through natural selection. (shrink)

Biologists and philosophers have long recognized the importance of species, yet species concepts serve two masters, evolutionary theory on the one hand and taxonomy on the other. Much of present-day evolutionary and systematic biology has confounded these two roles primarily through use of the biological species concept. Theories require entities that are real, discrete, irreducible, and comparable. Within the neo-Darwinian synthesis, however, biological species have been treated as real or subjectively delimited entities, discrete or nondiscrete, and they are often capable (...) of being decomposed into other, smaller units. Because of this, biological species are generally not comparable across different groups of organisms, which implies that the ontological structure of evolutionary theory requires modification. Some biologists, including proponents of the biological species concept, have argued that no species concept is universally applicable across all organisms. Such a view means, however, that the history of life cannot be embraced by a common theory of ancestry and descent if that theory uses species as its entities.These ontological and biological difficulties can be alleviated if species are defined in terms of evolutionary units. The latter are irreducible clusters of reproductively cohesive organisms that are diagnosably distinct from other such clusters. Unlike biological species, which can include two or more evolutionary units, these phylogenetic species are discrete entities in space and time and capable of being compared from one group to the next. (shrink)

The continuing discussion of the species problem suffers from the lack of a coherent ontological theory as a basis for determining whether species have an ontological status. It has attempted to apply a full-fledged metaphysical theory to the species problem: the ontology of Mario Bunge. In doing so a few ontological fundamentals including system, individual, real and conceptual object, and law are briefly introduced. It is with the help of these fundamentals that an analysis of the species-as-individuals thesis is carried (...) out, concluding that species are not individuals (things), but natural kinds, and that they have no ontological status. In contradistinction to the traditional view of natural kinds involving possible worlds metaphysics and semantics a notion of natural kind is given in terms of the state space approach and of nomological equivalence. (shrink)

The longstanding species problem in biology has a history that suggests a solution, and that history is not the received history found in many texts written by biologists or philosophers. The notion of species as the division into subordinate groups of any generic predicate was the staple of logic from Aristotle through the middle ages until quite recently. However, the biological species concept during the same period was at first subtly and then overtly different. Unlike the logic sense, which relied (...) on definitions of the essence of both genus and species, biological species from the time of Epicurus were consistently considered to involve a reproductive element: in short, living species relied not on essential definitions, but on the generative cause, which might not be definable. I term this the generative conception of species: species were the generation by reproduction of form. This undercuts the claim that species before Darwin were essentialist, and divorces the notion of a type from that of essence. In fact, as late as the end of the nineteenth century, logicians explicitly treated biological “species” as a homonym only of logical essentialist species, and permitted considerable deviation from the type or form. At every point, species in logic were thought to be a subset, in effect, of some more general notion. I sketch a history of both philosophical and biological traditions of the species concept, before turning to the current conceptions. These are reconsidered in the light of this history, and in particular Mayr’s changing views are shown to be somewhat Whiggish, historiographically. Of the many touted biological species concepts, only one of which (Mayr’s) is called _the_ Biological Species Concept, none appears to capture all the relevant facts, intuitions, and operational requirements of biology. Cladistic conceptions, however, have much in common with the older philosophical literature, in that the natural group of cladism is the clade, or monophyletic group. After considering the Individuality Thesis, and the metaphysics of species, we see that species are the most particular terminal taxa in a clade, and that they are “defined” in terms of the particular synapomorphies, or evolved characters, that are causally responsible for keeping the lineages that organisms form distinct from one another. In this way, we can remain within the generative conception of species that has been in play for over two millennia, and yet avoid the pitfalls of prior attempts to find a universal conception of species. (shrink)

This paper isolates a hard, long-standing species problem: developing a comprehensive and exacting theory about the constitutive conditions of the species category, one that is accurate for most of the living world, and which vindicates the widespread view that the species category is of more theoretical import than categories such as genus, sub-species, paradivision, and stirp. The paper then uncovers flaws in several views that imply we have either already solved that hard species problem or dissolved it altogether – so-called (...) We Are Done views. In doing so the paper offers new criticisms of the general lineage species concept (GLSC), evolutionary species concept (EvSC), biological species concept (BSC), other similar concepts, Ereshefsky’s eliminative pluralism about the species category, and both Mishler’s pessimism and Wilkins’ phenomenalism about that category. Opposed to We Are Done views, the paper argues for a Revving Up view, on which we are nearly ready to begin the hard species problem in earnest. To help work towards these conclusions, the paper begins with an outline of a new kind of view of species (Barker 2019a), which proposes they are feedback systems of a mathematically specifiable and empirically testable sort. (shrink)

Far from being rigorously defined, the concept of species in a biologicalsense has suffered from imprecision since Charles Darwin. This is mainlydue to the absence of a definition that allows to combine within eachspecies the organisms that are considered part of it. The objective of thiswork is to show, on the one hand, the diversity of characterizations of theconcept of species as well as their respective problems and, on the other,the different sustainable ontological positions. As a consequence of theaforementioned imprecision, (...) the ethical consequences that this entails inthe debate about speciesism are analyzed. (shrink)

There is a perennial philosophical dream of a certain natural order for the natural kinds. The name of this dream is ‘the hierarchy requirement’. According to this postulate, proper natural kinds form a taxonomy which is both unique and traditional. Here I demonstrate that complex scientific objects exist: objects which generate different systems of scientific classification, produce myriad legitimate alternatives amongst the nonetheless still natural kinds, and make the hierarchical dream impossible to realize, except at absurdly great cost. Philosophical hopes (...) for a certain order in nature cannot be fulfilled. Natural kinds crosscut one another, ubiquitously so, and this crosscutting spells the end of the hierarchical dream. (shrink)

These preprints were automatically compiled into a PDF from the collection of papers deposited in PhilSci-Archive in conjunction with the PSA 2018.

Speciation—the origin of new species—has been one of the most active areas of research in evolutionary biology, both during, and since the Modern Synthesis. While the Modern Synthesis certainly shaped research on speciation in significant ways, providing a core framework, and set of categories and methods to work with, the history of work on speciation since the mid-twentieth century is a history of divergence and diversification. This piece traces this divergence, through both theoretical advances, and empirical insights into how different (...) lineages, with different genetics and ecological conditions, are shaped by very different modes of diversification. (shrink)

We argue that the logical outcome of the cladistics revolution in biological systematics, and the move towards rankless phylogenetic classification of nested monophyletic groups as formalized in the PhyloCode, is to eliminate the species rank along with all the others and simply name clades. We propose that the lowest level of formally named clade be the SNaRC, the Smallest Named and Registered Clade. The SNaRC is an epistemic level in the classification, not an ontic one. Naming stops at that level (...) because there is no currently acceptable evidence for clades within it, not because no smaller clades exist. Later, included clades may be named. They would then become the SNaRCs, while the original SNaRC would keep its original name. We argue that all theoretical tasks of biology, in evolution and ecology, as well as practical tasks such as conservation assessment, are better approached using this rankless phylogenetic approach. (shrink)

A number of influential biologists are currently pursuing efforts to restore previously extinct species. But for decades, philosophers of biology have regarded “de-extinction” as conceptually incoherent. Once a species is gone, it is gone forever. We argue that a range of metaphysical, biological, and ethical grounds for opposing de-extinction are at best inconclusive and that a pragmatic stance that allows for its possibility is more appealing.

The aim of this article is to discuss the nature of disagreement in scientific ontologies in the light of case studies from biology and cognitive science. I argue that disagreements in scientific ontologies are usually not about purely factual issues but involve both verbal and normative aspects. Furthermore, I try to show that this partly non-factual character of disagreement in scientific ontologies does not lead to a radical deflationism but is compatible with a “normative ontological realism.” Finally, I argue that (...) the case studies from the empirical sciences challenge contemporary metaontological accounts that insist on exactly one true way of “carving nature at its joints.”. (shrink)

The continuing discussion of the species problem suffers from the lack of a coherent ontological theory as a basis for determining whether species have an ontological status. It has attempted to apply a full-fledged metaphysical theory to the species problem: the ontology of Mario Bunge. In doing so a few ontological fundamentals including system, individual, real and conceptual object, and law are briefly introduced. It is with the help of these fundamentals that an analysis of the species-as-individuals thesis is carried (...) out, concluding that species are not individuals (things), but natural kinds, and that they have no ontological status. In contradistinction to the traditional view of natural kinds involving possible worlds metaphysics and semantics a notion of natural kind is given in terms of the state space approach and of nomological equivalence. (shrink)

Biologists and philosophers of biology typically regard essentialism about speciesas incompatible with modern Darwinian theory. Analytic metaphysicians such asKripke, Putnam and Wiggins, on the other hand, believe that their essentialist thesesare applicable to biological kinds. I explore this tension. I show that standard anti-essentialist considerations only show that species do not have intrinsic essential properties. I argue that while Putnam and Kripke do make assumptions that contradict received biological opinion, their model of natural kinds, suitably modified, is partially applicable to (...) biological species. However, Wiggins'' thesis that organisms belong essentially to their species is untenable, given modern species concepts. I suggest that Putnam''s, Kripke''s and Wiggins'' errors stem from adopting an account of the point of scientific classification which implies that relationally-defined kinds are likely to be of little value, an account which is inapplicable to biology. (shrink)

The Empiricist or Lockean view says natural kinds do not exist objectively in nature but are practical categories reflecting use of words. The Modern, Ostensive view says they do exist, and one can refer to such a kind by ostention and recursion, assuming his designation of it is related causally to the kind itself. However, this leads to a problem: Kinds are abstract repeatables, and it seems impossible that abstractions could have causal force. In defence of the Modern view, I (...) suggest we can think of kinds as — or as like — ecological niches existing in nature, which are causally effective by virtue of the fact that they predictively determine (some) properties of the things that happen to occupy them. (shrink)

Biological science uses multiple species concepts. Order can be brought to this diversity if we recognize two key features. First, any given species concept is likely to have a patchwork structure, generated by repeated application of the concept to new domains. We illustrate this by showing how two species concepts (biological and ecological) have been modified from their initial eukaryotic applications to apply to prokaryotes. Second, both within and between patches, distinct species concepts may interact and hybridize. We thus defend (...) a semantic picture of the species concept as a collection of interacting patchwork structures. Thus, although not all uses of the term pick out the same kind of unit in nature, the diversity of uses reflects something more than mere polysemy. We suggest that the emphasis on the use of species to pick out natural units is itself problematic, because that is not the term’s sole function. In particular, species concepts are used to manage inquiry into processes of speciation, even when these processes do not produce clearly delimited species. (shrink)

This paper uses two case studies to explore an interest-relative view of taxonomy and how it complements kind pluralism in biology. First, I consider the ABC island bear, which can be correctly classified into more than one species. I argue that this classificatory pluralism can be explained by reference to the range of alternative explanatory interests in biology. In the second half of the paper, I pursue an interest-relative view of classification more generally. I then apply the resultant view to (...) a second case study: whether whales are fish. I argue that this question is not one about scientific vs folk usage, as has been assumed. I also develop a new view: that Fish should be rejected as a category, both from the point of view of biological science, and from the point of view of folk taxonomy. Along the way, I use the interest-relative view to shed light on the circumstances under which higher taxa should be accepted as legitimate categories for biological science. (shrink)

We argue that the economy of nature constitutes an invocation of structure in the biological sciences, one largely missed by philosophers of biology despite the turn in recent years toward structural explanations throughout the philosophy of science. We trace a portion of the history of this concept, beginning with the theologically and economically grounded work of Linnaeus, moving through Darwin’s adaptation of the economy of nature and its reconstitution in genetic terms during the first decades of the Modern Synthesis. What (...) this historical case study reveals, we argue, is a window into the shifting landscape of the explanatory and ontic uses of structural concepts. In Linnaeus, the economy of nature has both ontic and explanatory import; in Darwin the ontic and explanatory aspects start to come apart ; and finally, in the Modern Synthesis, the economy of nature is replaced by the conceptual toolkit of population genetics, the structural elements of which are nearly entirely explanatory. Having traced a historical trajectory of structural concepts that moves from an ontic formulation to an increasingly explanatory one, we conclude by outlining some insights for structural realism. (shrink)

This paper outlines an alternative perspective on species that avoids some of the underlying assumptions held by the BSC and other gene-centred species concepts. It begins with a characterisation of the species problem and some of the assumptions underpinning conceptions of species. In particular, the underlying bias of some conceptions (such as the BSC) to focus exclusively on the adult stage of the life cycle in articulating what a species is.

This article characterizes various species concepts in terms of set-theoretic models that license biological inferences and illustrates the logical connections among different species concepts. Species in this construal are abstract models, rather than biological or even tangible entities, and relate to individual organisms via representation, rather than the membership or mereological whole/part relationship. The proposal sheds new light on vexed issues of species and situates them within broader philosophical contexts of model selection, scientific representation, and scientific realism.

College of Medicine, University of South Alabama Mobile, AL 36688-0002, USA wbp501{at}jaguar1.usouthal.edu ' + u + '@' + d + ' '//--> Abstract Recent work in viral genomics has shown that bacteriophages exhibit a high degree of mosaicism, which is most likely due to a long history of prolific horizontal gene transfer (HGT). Given these findings, we argue that each of the most plausible attempts to properly classify bacteriophages into distinct species fail. Mayr's biological species concept fails because there is (...) no useful viral analog to sexual reproduction. Phenetic species concepts fail because they obscure the mosaicism and the rich reticulated viral histories. Phylogenetic species concepts, even when extended to take into account reticulation, fail because there is no non-arbitrary distinction between recombination events that create a new viral species and those that do not. There is good reason to think that bacteriophages, arguably the Earth's most abundant biological agent, evolve without forming species. Introduction The Biology of Viruses 2.1 Bacteriophage life cycles 2.2 Mechanisms of HGT The Species Problem and Species Concepts 3.1 Phenetic species concepts 3.2 The biological species concept 3.3 Phylogenetic species concepts 3.4 The ecological species concept 3.5 Homeostatic property cluster species Viruses and Species Taxonomy Reticular Phylogenies Conclusion CiteULike Connotea Del.icio.us What's this? (shrink)

The circumscription of taxa and classification of organisms are fundamental tasks in the systematization of biological diversity. Their success depends on a unified idea concerning the species concept, evolution, and taxonomy; paradoxically, however, it requires a complete distinction between taxa and evolutionary units. To justify this view, I discuss these three topics of systematics. Species concepts are examined, and I propose a redefinition for the Taxonomic Species Concept based on nomenclatural properties, in which species are classes conventionally represented by a (...) binomial. Speciation is subsequently discussed, to demonstrate that concepts on the evolutionary process are damaged when species are considered as evolutionary units. Speciation should be considered a transition among patterns of a population and, consequently, always a sympatric process. This view contrasts with the majority of speciation models, which analyze cladogeneses and classify speciation geographically, usually considering allopatry the essential condition for the differentiation process. Finally, taxonomy is considered, to show that the equivalence between evolutionary and taxonomic units may also damage the practice of biological systematization. Principles and rules of nomenclature and classification should offer freedom to accommodate divergent opinions about systematics and to incorporate the evolution of knowledge; therefore, they should remain independent of biological theories. (shrink)

Species are considered the basic unit of biological classification and evolution. Hence, they are used as a benchmark in several fields, although the ontological status of such a category has always been a matter of debate. This paper aims to discuss the problem of the definition of species within the new mechanistic approach. Nevertheless, the boundary between entities, activities, and mechanisms remains difficult to establish and always requires an analysis of what is meant by explanation. As a case study, the (...) paper describes the debate concerning the species category by considering different kingdoms: Animals, Bacteria, and Fungi. The inherently biological differences between those groups prevent the use of a single, universally applicable concept of species that could fit the mechanisms responsible for the variability present in these kingdoms. The same issue is encountered within each group, as highlighted through a focus on mammals and microbes. This controversy has given rise to opposite approaches, namely: monism, which looks for a single definition that might account for all species, and pluralism, which admits that different groups of organisms require somewhat different definitions. In order to develop an adequate definition of species, we propose to apply a new mechanistic framework, which considers the ontic-epistemic dimensions of scientific explanation in close parallel. The apt correlation between epistemic and the ontic aspects highlights the way in which the concept of species and the reference to data are strictly co-determined. This suggests that the concept of species is better understandable within a dual ontic-epistemic approach. (shrink)

Evolution in its contemporary meaning in biology typically refers to the changes in the proportions of biological types in a population over time (see the entry on the concept of evolution to 1872 for earlier meanings). As evolution is too large of a topic to address thoroughly in one entry, the primary goal of this entry is to serve as a broad overview of contemporary issues in evolution with links to other entries where more in-depth discussion can be found. The (...) entry begins with a brief survey of definitions of evolution, followed by a discussion of the different modes of evolution and related philosophical issues, and ends with a summary of other topics in the philosophy of evolution focusing particularly on topics covered in this encyclopedia. (shrink)

It has increasingly been recognised that units of biological classification cannot be identified with the units of evolution. After briefly defending the necessity of this distinction I argue, contrary to the prevailing orthodoxy, that species should be treated as the fundamental units of classification and not, therefore, as units of evolution. This perspective fits well with the increasing tendency to reject the search for a monistic basis of classification and embrace a pluralistic and pragmatic account of the species category. It (...) also provides a diagnosis of the paradoxical but popular idea that species are individuals: Species are not individuals, but the units of evolution are. (shrink)

The project of this paper is to understand what a phylogenetic tree represents and to discuss some of the implications that this has for the practice of systematics. At least the first part of this task, if not both parts, might appear trivial—or perhaps better suited for a single page in a textbook rather than a scholarly research paper. But this would be a mistake. While the task of interpreting phylogenetic trees is often treated in a trivial way, their interpretation (...) is tied to foundational conceptual questions at the heart of systematics—questions whose answers are hotly disputed. I have previously argued that widely shared ideas about the meaning and interpretation of phylogenetic trees are inconsistent with species concepts other than some genealogical version of a phylogenetic species concept (Velasco 2008). Here I rely on a similar approach and concentrate on the implications of the necessary conditions underlying the inferences that we make using phylogenetic trees. I argue that common practices for the interpretation and use of trees are in conflict and that unacceptable principles about species as units of phylogeny must be given up. According to the view that I will develop, all phylogenetic trees depict the history of populations. The branches on trees represent collections of population lineages through time and the splits represent population lineage splits. This is true regardless of whether the tips of the trees are themselves populations, or are species or higher taxa. Although this conclusion might be paired naturally with a view that species must be monophyletic groups, this population-centric view of trees is independent of that view of species. If we still want to have species that are paraphyletic groups of populations, this is permissible as long as we also do not treat species as the units of phylogeny. This population-centric view opposes a species-centric view of phylogeny and might be called a “rank-free” approach since it entails that we do not need to determine which groups are species (which is partly a ranking question) in order to build a tree. This conclusion and the argument for it are meant to be consistent with, but not require, acceptance of the conclusions of Velasco (2008) regarding species. (shrink)

In this paper, I address the charge that the category species should be abandoned in biological work. The widespread appeal to species in scientific discourse provides a presumption in favor of the category’s usefulness, but a defeasible presumption. Widely acknowledged troubles attend species: these troubles might render the concept unusable by showing that ‘species’ is equivocal or meaningless or in some similar way fatally flawed. Further, there might be better alternatives to species. I argue that the presumption in favor of (...) species is not defeated on these scores. Troubles attending species, which arise on account of contextual variation attending the use of ‘species’, do not indicate that the concept is unusable. And alternatives to the use of ‘species’, which have been proposed in connection with rank-free systematics and in connection with conservation efforts, fail to provide a proper replacement for species. (shrink)

This is an essay about ethics and environmental responsibility. The thesis is that biologic species qua species--not only as collections of individuals or as elements of ecosystems--deserve moral regard. The argument establishes moral considerability on powers and freedoms of relative self-determination and autonomy. It is argued that species are living beings in their own right with their own projects and interests which deserve special regard. The essay draws from the arguments of Plato, Aristotle, Plotinus, Boethius, Avicenna, Maimonides, Leibniz, Spinoza, Kant, (...) and others, concerning the moral value of natural beings, but situates itself in the contemporary dialogue of environmental ethics. Lengthy consideration is given to species concepts defended by evolution theorists, biological systematists, and ecologists. ;The argument claims that natural beings, including species, have moral value because they have projects and interests which make a legitimate, but not universal, claim on the moral agent. Beings make moral claims when they are integral and integrating, individual, and concreative--conditions comparable to those with which we describe the moral status of a person. We may call such beings rational by analogy to the integration and singularity of intellect, and confer upon them analogous moral consideration. They are due regard in proportion to their projects in the same sense that moral subjects are due regard for having the projects of moral subjects. (shrink)

Many phylogenetic systematists have criticized the Biological Species Concept (BSC) because it distorts evolutionary history. While defenses against this particular criticism have been attempted, I argue that these responses are unsuccessful. In addition, I argue that the source of this problem leads to previously unappreciated, and deeper, fatal objections. These objections to the BSC also straightforwardly apply to other species concepts that are not defined by genealogical history. What is missing from many previous discussions is the fact that the Tree (...) of Life, which represents phylogenetic history, is independent of our choice of species concept. Some species concepts are consistent with species having unique positions on the Tree while others, including the BSC, are not. Since representing history is of primary importance in evolutionary biology, these problems lead to the conclusion that the BSC, along with many other species concepts, are unacceptable. If species are to be taxa used in phylogenetic inferences, we need a history-based species concept. (shrink)

Species are thought by many to be important units of evolution. In this paper, I argue against that view. My argument is based on an examination of the role of species in the synthetic theory of evolution. I argue that if one adopts a gradualist view of evolution, one cannot make sense of the claim that species are units in the minimal sense needed to claim that they are units of evolution, namely, that they exist as discrete entities over time. (...) My second argument is directed against an appeal to Eldredge and Gould's theory of punctuated equilibria to support the claim that species are units of evolution. If one adopts their view, it may be possible to identify discrete temporal entities that can plausibly be termed species, but there is no reason to claim that those entities are units of evolution. Thus, on two plausible interpretations of the role of natural selection in the process of evolution, species are of no special importance. I then consider some of the reasons why species have been thought to be important evolutionary units by many contemporary evolutionary biologists. Finally, I discuss briefly the implications of this conclusion for evolutionary biology. (shrink)

Concepts and methods originating in one discipline can distort the structure of another when they are applied to the latter. I exemplify this mostly with reference to systematic biology, especially problems which have arisen in relation to the nature of species. Thus the received views of classes, individuals (which term I suggest be replaced by units to avoid misunderstandings), and sets are all inapplicable, but each can be suitably modified. The concept of fuzzy set was developed to deal with species (...) and I defend its applicability. Taxa at all levels are real and participate in biological processes. Analysis of cause and pattern provides the deep structure in which metabiology is grounded; violation of this principle has led to diverse errors in biology. (shrink)