Classifying is a fundamental operation in the acquisition of knowledge. Taxonomic theory can help students of cognition, evolutionary psychology, ethology, anatomy, and sociobiology to avoid serious mistakes, both practical and theoretical. More positively, it helps in generating hypotheses useful to a wide range of disciplines. Composite wholes, such as species and societies, are “individuals” in the logical sense, and should not be treated as if they were classes. A group of analogous features is a natural kind, but a group of (...) homologous features is not. Imposing hypotheses justified only on the basis of nominalist, realist, phenomenalist, or conceptualist metaphysics upon the neurophysiology of organisms or upon the causes of behavior exemplifies the “psychologist's fallacy” of William James. Levels should be distinguished from their members and from classes of levels, and the ontological status of entities ranked at levels should be made clear. It is important not to confuse such categories as substance and process with one another. Several genetical terms, such as “gene” and chromosome,” are even more equivocal than has been realized. Discussions about units of selection, behavior, and thinking suffer from the ambiguity of a “unit of” an entity. An important source of misunderstanding about natural selection is the habit of treating it as an “agent”: in an important sense, natural selection does not “act” at all. (shrink)

I defend a view of the species category, pluralistic realism, which is designed to do justice to the insights of many different groups of systematists. After arguing that species are sets and not individuals, I proceed to outline briefly some defects of the biological species concept. I draw the general moral that similar shortcomings arise for other popular views of the nature of species. These shortcomings arise because the legitimate interests of biology are diverse, and these diverse interests are reflected (...) in different legitimate approaches to the classification of organisms. In the final section, I show briefly how the pluralistic approach can help to illuminate some areas of biological and philosophical dispute. (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)

Various philosophers and evolutionary biologists have recently defended the thesis that species are individuals rather than sets. A decade of debates, however, did not suffice to settle the matter. Conceptual analysis shows that many of the key terms involved are ambiguous. Current disagreements should dissolve once this is recognized. Explication of the concepts involved leads to new programs for philosophical research. It could also help biology by showing how extant controversies concerning evolution may have conceptual rather than factual roots.

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.

This paper presents the leading idea of my doctoral dissertation and thus has been shaped by the reactions of all the members of my thesis committee: Charles Chastain, Walter Edelberg, W. Kent Wilson, Dorothy Grover, and Charles Marks. I am especially grateful for the help of Professors Chastain, Edelberg, and Wilson; each worked closely with me at one stage or another in the development of the ideas contained in the present work. Shorter versions of this paper were presented at the (...) 47th Annual Northwest Conference on Philosophy (1995), the 1996 Mid-South Philosophy Conference, the 1997 meeting of the Central Division of the American Philosophical Association, and at the University of Washington, Seattle; thanks to all audiences for their insightful comments and questions and also to my conference commentators, Eric Gampel, Jonathan Cohen, and Bruce Glymour, respectively, each of whom offered a thoughtful critique. Lastly, I extend my gratitude to anonymous referees, including two from Mind and Language, whose remarks led to significant improvements in the paper. Address for correspondence: 13416, 4th Ave. S., Seattle, WA 98168, USA E-mail: [email protected].. (shrink)

This paper takes a hierarchical approach to the question whether species are individuals or natural kinds. The thesis defended here is that species are spatiotemporally located complex wholes (individuals), that are composed of (i.e., include) causally interdependent parts, which collectively also instantiate a homeostatic property cluster (HPC) natural kind. Species may form open or closed genetic systems that are dynamic in nature, that have fuzzy boundaries due to the processual nature of speciation, that may have leaky boundaries as is manifest (...) in lateral gene transfer and introgression, that may be of multiple origins through hybridization, and that may split and merge and split again over time. The identity conditions of species qua individuals will have to be anchored in their history, rather than in their unique evolutionary origin. Species qua historically conditioned HPC natural kinds requires the kind to be mereologically structured, subject to the part-whole relation rather than the membership relation. This implies that there can be more than one kind of natural kinds. (shrink)

The philosophy of biology is witnessing an increasing enthusiasm for what can be called “individuals thinking”. Individuals thinking is a perspective on the metaphysics of biological entities according to which conceiving of them as individuals rather than kinds enables us to expose ongoing metaphysical debates as focusing on the wrong question, and to achieve better accounts of the metaphysics of biological entities. In this paper, I examine two cases of individuals thinking, the claim that species are individuals and the claim (...) that life on Earth is an individual. I argue that these claims fail to do the metaphysical work that one would want them to do. I highlight problems with the specific claims as well as with the general notion of ‘individual’, and argue that naturalistic metaphysicians of biology should think of the metaphysical status of theoretical entities, such as species and life, as fundamentally theory-dependent. This implies a metaphysical pluralism, that allows that in some theories species, life, and other such entities may feature as individuals, whereas in others they may feature as kinds. (shrink)

Species in biology are traditionally perceived as kinds of organisms about which explanatory and predictive generalizations can be made, and biologists commonly use species in this manner. This perception of species is, however, in stark contrast with the currently accepted view that species are not kinds or classes at all, but individuals. In this paper I investigate the conditions under which the two views of species might be held simultaneously. Specifically, I ask whether upon acceptance of an ontology of species (...) as diachronic segments of the tree of life species can perform the epistemic role of kinds of organisms to which explanatory and predictive generalizations apply. I show that, for species-level segments of the tree of life, several requirements have to be met before the performance of this epistemic role is possible, and I argue that these requirements can be met by defining species according to the Composite Species Concept proposed by Kornet and McAllister in the 1990s. (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)

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 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 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)

Abstract The ‘species problem’ in the philosophy of biology concerns the nature of species. Various solutions have been proposed, including arguments that species are sets, classes, natural kinds, individuals, and homeostatic property clusters. These proposals parallel debates in ecology as to the ontology and metaphysics of populations, communities and ecosystems. A new solution—that species are processes—is proposed and defended, based on Robert Ulanowicz’s metaphysics of process ecology. As with ecological systems, species can be understood as emergent, autocatalytic systems with propensities (...) for centripetality and mutuality in the course of dynamically balancing ascendency (order and persistence) and overhead (randomness and change). The species-as-processes perspective accords with the Ulanowicz’s postulates of process ecology and it can be accommodated by existing theories of species—particularly in a reframing of Richard Boyd’s metaphysics such that species are homeostatic process clusters. Rather than contending that process-based metaphysics is the only, best or true account of species, a pluralist-realist approach is advocated based on the pragmatic principles that are reflected in modern view of species and ecology. If species are understood to be comprised of processes and to be emergent processes themselves, there are important implications for the life sciences, including: animal models in medical and environmental studies, conservation biology, extinction, biodiversity, restoration ecology, and evolutionary biology. Content Type Journal Article Category Invited Paper Pages 1-30 DOI 10.1007/s10516-011-9169-5 Authors Jeffrey A. Lockwood, Department of Philosophy, University of Wyoming, Laramie, WY 82071, USA Journal Axiomathes Online ISSN 1572-8390 Print ISSN 1122-1151. (shrink)

I defend a view of the species category, pluralistic realism, which is designed to do justice to the insights of many different groups of systematists. After arguing that species are sets and not individuals, I proceed to outline briefly some defects of the biological species concept. I draw the general moral that similar shortcomings arise for other popular views of the nature of species. These shortcomings arise because the legitimate interests of biology are diverse, and these diverse interests are reflected (...) in different legitimate approaches to the classification of organisms. In the final section, I show briefly how the pluralistic approach can help to illuminate some areas of biological and philosophical dispute. (shrink)

Weak links, in the form of inadequacies in both reasoning and supporting evidence, exist at several critical steps in the derivation of an hierarchical concept of evolution from punctuated equilibria. Punctuation itself is predicated on a distorted reading of phyletic change as phyletic gradualism, and of allopatric speciation as the instantaneous formation of unchanging typological taxa. The concept of punctuation is further confounded by the indescriminate employment of the same term to denote both a causal explanation for evolutionary change and (...) an outcome of substantiated evolutionary processes. Even when the intended usage for the term is specified, each denotation of punctuation entails respective drawbacks. As a causal explanation, punctuation clearly belongs to the class of quantum theories with all their attendant impedimenta, including special salsatory non-adaptive mechanisms of evolutionary change. Redefinition of punctuation as a pattern of morphologic change reduces it to one possible outcome of known microevolutioanry processes, thus obviating any need for an hierarchical explanation of macroevolution. While vacillation between usages has preserved the term in the literature, the end result of this obfuscation has been a circle of faulty reasoning in which the pattern of punctuation is invoked as its own proof. Widespread confusion concerning what constitutes an adequate test of punctuation is directly attributable to imprecision in both the original and revised formulations of the concept.The argument for species-level selection is based on the typological and philosphically flawed premise of species as individuals, and further requires the hypothesis of heritable emergent properties, for which empirical evidence is lacking. (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)

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)

Essentialism--understood as the doctrine that there are natural kinds--can be sustained with respect to the most fundamental physical entities of the world, as I elsewhere argue. In this paper I take up the question of the existence of natural kinds among complex structures built out of these elementary ones. I consider a number of objections to essentialism, in particular Locke's puzzle about the existence of borderline cases. A number of recent attempts to justify biological taxonomy are critically examined. I conclude (...) that theory partially justifies such taxonomies but supports only a weaker form of essentialism. (shrink)

I examine the ways in which the theological and philosophical debate surrounding transhumanism might profit by a detailed engagement with contemporary biology, in particular with the mainline accounts of species and speciation. After a short introduction, I provide a very brief primer on species concepts and speciation in contemporary biological taxonomy. Then in a third section I draw out some implications for the prospects of our being able intentionally to intervene in human evolution for the production of new species out (...) of Homo sapiens. In a fourth section Account of Human Nature? And Where Does This Leave Transhumanism?”) I bring in the debate over the proper relationship between biological and theological conceptions of human nature, laying out the major options available and considering their possible implications for our understanding of transhumanism. In a fifth section several concrete examples are drawn out pertaining to particular subdisciplines within theology. I conclude by briefly laying out some suggestions for future work, focusing on tasks that theologians specifically ought to pursue. (shrink)

One question asked repeatedly in the history of Christology is the following: given that the incarnation was God’ s chosen method of redeeming us, why did God become human by the cooperation of the Blessed Virgin Mary? Why not just create a human body and soul ex nihilo and simultaneously with that creation have God the Son assume this new instance of human nature? In answer, Augustine for instance argues that the latter option would have been a legitimate means of (...) incarnation, but that it was not as fitting as the method actually employed. Aquinas agrees. By contrast, John of Damascus seems to think that the ex nihilo option would not have constituted a genuine assumption of human nature, such that redemption required the cooperation of the Theotokos. I argue that insights provided by contemporary biology support St. John’s perspective, insofar as modern biological taxonomy suggests that lineal descent is a necessary condition for belonging to a species. As such, to take on a genuinely human nature God had to enter into the existing human lineage; creating a new ‘human’ body and soul ex nihilo would not have sufficed. (shrink)

The paper defends the doctrine that Linnaean taxa, including species, have essences that are, at least partly, underlying intrinsic, mostly genetic, properties. The consensus among philosophers of biology is that such essentialism is deeply wrong, indeed incompatible with Darwinism. I argue that biological generalizations about the morphology, physiology, and behavior of species require structural explanations that must advert to these essential properties. The paper concludes by summarizing my responses to the objection that, according to current “species concepts,” species are relational, (...) and to the objection that essentialism cannot accommodate features of Darwinism associated with variation and change. (shrink)

The article defends the doctrine that Linnaean taxa, including species, have essences that are, at least partly, underlying intrinsic, mostly genetic, properties. The consensus among philosophers of biology is that such essentialism is deeply wrong, indeed incompatible with Darwinism. I argue that biological generalizations about the morphology, physiology, and behavior of species require structural explanations that must advert to these essential properties. The objection that, according to current “species concepts,” species are relational is rejected. These concepts are primarily concerned with (...) what it is for a kind to be a species and throw little light on the essentialist issue of what it is for an organism to be a member of a particular kind. Finally, the article argues that this essentialism can accommodate features of Darwinism associated with variation and change. (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)

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 recognition of species proceeds by two fairly distinct phases: (1) the sorting of individuals into groups or basic taxa (‘discovery’) (2) the checking of those taxa as candidates for species-hood (‘justification’). The target here is a rational reconstruction of phase 1, beginning with a discussion of key terms. The transmission of ‘meaning’ is regarded as bimodal: definition states the intension of the term, and diagnosis provides a disjunction of criteria for recognition of its extension. The two are connected by (...) a spectrum, with purely theoretical definition at one pole and purely ‘operational’ diagnosis at the other, with the more operational elements explained by the more theoretical. The current plethora of species concepts provides a good example. Accepting the Ghiselin–Hull thesis, that a species is an individual, a basic taxon is therefore also an individual with organisms as its parts. In a generalised synchronic individual its parts are conceptually integrated by an integrating principle (IP), which consists of a relation applying within a plan or rule. Fully developed, such an IP ensures the maximisation of the information content of the individual. A diachronic individual is then the set of its component synchronic parts, and its IP is provided by near-identity in an appropriate space-time (not necessarily physical). The integration of parts of an individual is illuminated by Gasking's concept of a proper group (in this case a chain-group), whose members are related by the relation serially fitting together with, the IP completed by an appropriate plan or rule. Gasking also applied the term cluster to a proper group persisting over a substantial period of time, individuated by any member acting as focus. A basic taxon is therefore a cluster of individuals, integrated by the relation significantly taxonomically similar and the rule in character-space-time. The nature of those concepts is discussed and defended. A species will inherit certain of the attributes of the preceding basic taxon (taxa). In at least the synchronic version its parts (individuals) will resemble each other significantly, providing the intuitive applicability of ‘members of’ and ‘instances of’ a species. Also, the notion that a species’ name is given by pure ostension, via a name-bearer (holotype) is empirically incoherent: the name cannot be applied in practice without an appropriate set of diagnostic traits. (shrink)

Whether or not the particular view of generic sentences articulated above is correct, it is quite clear that the study of generic terms and the truth-conditions of generic sentences touches on the representation of other parts of the grammar, as well as on how the world around us is reflected in language. I would hope that the problems mentioned above will highlight the relevance of semantic analysis to other apparently distinct questions, and focus attention on the relevance of linguistic problems (...) to other already established areas of inquiry. (shrink)