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)

An examination of the post-Darwinian history of biological taxonomy reveals an implicit assumption that the definitions of taxon names consist of lists of organismal traits. That assumption represents a failure to grant the concept of evolution a central role in taxonomy, and it causes conflicts between traditional methods of defining taxon names and evolutionary concepts of taxa. Phylogenetic definitions of taxon names (de Queiroz and Gauthier 1990) grant the concept of common ancestry a central role in the definitions of taxon (...) names and thus constitute an important step in the development of phylogenetic taxonomy. By treating phylogenetic relationships rather than organismal traits as necessary and sufficient properties, phylogenetic definitions remove conflicts between the definitions of taxon names and evolutionary concepts of taxa. The general method of definition represented by phylogenetic definitions of clade names can be applied to the names of other kinds of composite wholes, including populations and biological species. That the names of individuals (composite wholes) can be defined in terms of necessary and sufficient properties provides the foundation for a synthesis of seemingly incompatible positions held by contemporary individualists and essentialists concerning the nature of taxa and the definitions of taxon names. (shrink)

I adopt a cladistic view of species, and explore the possibility that there exists an equally valuable cladistic view of organismic traits. This suggestion seems to run counter to the stress on functional views of biological traits in recent work in philosophy and psychology. I show how the tension between these two views can be defused with a multilevel view of biological explanation. Despite the attractions of this compromise, I conclude that we must reject it, and adopt an essentially cladistic (...) conception of biological traits. (shrink)

The species category is defined as thesmallest historical individual within which there is a parental pattern of ancestry and descent. The use of historical individual in this definition is consistent with the prevailing notion that speciesper se are not involved in processes — they are effects, not effectors. Reproductive isolation distinguishes biparental historical species from their parts, and it provides a basis for understanding the nature of the evidence used to discover historical individuals.

This paper takes up the cause of species pluralism. An argument for species pluralism is provided and standard monist objections to pluralism are answered. A new form of species pluralism is developed and shown to be an improvement over previous forms. This paper also offers a general foundation on which to base a pluralistic approach to biological classification.

In addition to the distinction between species as a category and speciesas a taxon, the word species is ambiguous in a very different butequally important way, namely the temporal distinction between horizontal andvertical species. Although often found in the relevant literature, thisdistinction has thus far remained vague and undefined. In this paper the use ofthe distinction is explored, an attempt is made to clarify and define it, andthen the relation between the two dimensions and the implications of thatrelation are examined. (...) Using Darwin's analogy of language evolution forspeciesevolution, and by appealing to a major change in the conception of languagebetween 19th- and 20th-century linguistics, it is argued that the horizontaldimension has priority (pragmatic, epistemological, logical, and ontological)over the vertical dimension. This has immense ramifications for the modernspecies problem. Fundamentally, it favors horizontal species concepts oververtical ones. In so doing it places species realism on a much more securefoundation and largely undercuts species pluralism. In addition it raises aserious problem for the increasingly popular family of phylogenetic speciesconcepts, which generally suffer from a dimensionality confusion. However,thereis a recent trend within this family that attempts to restore the priority ofthe horizontal dimension. It is concluded that this trend should be affirmedandthat the species-as-individuals view should be abandoned. (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)

An examination of the post-Darwinian history of biological taxonomy reveals an implicit assumption that the definitions of taxon names consist of lists of organismal traits. That assumption represents a failure to grant the concept of evolution a central role in taxonomy, and it causes conflicts between traditional methods of defining taxon names and evolutionary concepts of taxa. Phylogenetic definitions of taxon names (de Queiroz and Gauthier 1990) grant the concept of common ancestry a central role in the definitions of taxon (...) names and thus constitute an important step in the development of phylogenetic taxonomy. By treating phylogenetic relationships rather than organismal traits as necessary and sufficient properties, phylogenetic definitions remove conflicts between the definitions of taxon names and evolutionary concepts of taxa. The general method of definition represented by phylogenetic definitions of clade names can be applied to the names of other kinds of composite wholes, including populations and biological species. That the names of individuals (composite wholes) can be defined in terms of necessary and sufficient properties provides the foundation for a synthesis of seemingly incompatible positions held by contemporary individualists and essentialists concerning the nature of taxa and the definitions of taxon names. (shrink)

The issue of whether species are individuals is now an old one; the literature abounds with arguments, counter-arguments and counter-counter-arguments for their individuality. The question I want to take up in this paper is not whether species are indeed individuals, but what ramifications their alleged individuality has for macroevolutionary theory.According to those biologists who argue for a new theory of macroevolution, the individuality of species is one of the fundamental premises of that theory. For example, Joel Cracraft writes of himself (...) and others thatThe issue of individuality… is at the heart of arguments of those evolutionary biologists who see a need to view the patterns and processes of evolution as being hierarchically arranged into microevolutionary and macroevolutionary levels (1987, p. 332). (shrink)

Although the term taxon is one of the most common concepts in biology, a range of its meanings cannot be comprehended by an universal definition. Usually, biologists construe their knowledge of “the same” taxon by substantially different interpretations, so they find themselves in need either to justify this “multiplication of taxon essences”, or to surmount their plurality unifying its interpretations into a single explanation of what a taxon is. In both cases, an ontological status (“reality”) of that taxon is questioned. (...) Therefore, discrepancy between universality of the taxon concept in biology and unavoidable plurality of its interpretations can be regarded as a source of problem of the taxon ontology. The present work aims to clarify the premises of this discrepancy using phenomenological approach. Three ways of the taxon positing (as a class, as a place in the world, and as a individualized body) have been distinguished. Taxon as a class is established by common essence that is shared by a set of living beings. These living beings are regarded as speculative objects beyond an idea of the world, i.e. as objects of the experimental science. A question about ontology of taxon as a class refers to the scholastic problem of universalia; its status can be defined within the scope of the nominalism/realism opposition. Taxon as a place of common appearance of the specimens is regarded in the context of the etiological relations unifying various entities into the entire world. Taxon as a place refers to a certain position in the Natural System that is construed as an etiological map of the world. In this case a specimen of a living being is known as a curiosity, i.e. representant of its relationships as well as of the place of its origin. Ontological status of a taxon as a place is to be clarified within the framework of the natural/artificial opposition. The positing of a taxon as a collective body marked off by limits of joint survival of living beings is characteristic for biology in the strict sense which arose in the very beginning of the 19 century. A taxon as a body established by the techniques of disciplinary power sensu M. Foucault extended from the human bodies to bodies of other living beings. The ontological status of a taxon as a collective body can be defined within the scope of the wild/domesticated opposition. Therefore, the discrepancy between the universality of the taxon concept and the plurality of its interpretations is underlayed by interpenetration of three distinct modi of taxon establishing. Distinguishing between these three modi can clarify sources of ontological problems concerned with the term taxon in each case when they arise. (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)

Recent work has suggested that conservation efforts such as restoration ecology and invasive species eradication are largely value-driven pursuits. Concurrently, changes to global climate are forcing ecologists to consider if and how collections of species will migrate, and whether or not we should be assisting such movements. Herein, we propose a philosophical framework which addresses these issues by utilizing ecological and evolutionary interrelationships to delineate individual ecological communities. Specifically, our Evolutionary Community Concept recognizes unique collections of species that interact and (...) have co-evolved in a given geographic area. We argue this concept has implications for a number of contemporary global conservation issues. Specifically, our framework allows us to establish a biological and science-driven context for making decisions regarding the restoration of systems and the removal of exotic species. The ECC also has implications for how we view shifts in species assemblages due to climate change and it advances our understanding of various ecological concepts, such as resilience. (shrink)

Species serve as both the basic units of macroevolutionary studies and as the basic units of taxonomic classification. In this paper I argue that the taxa identified as species by the Phylogenetic Species Concept (Mishler and Brandon 1987) are the units of biological organization most causally relevant to the evolutionary process but that such units exist at multiple levels within the hierarchy of any phylogenetic lineage. The PSC gives us no way of identifying one of these levels as the privileged (...) level on which taxonomic classifications can be based. (shrink)