Much clinical and ethnographic evidence suggests that humans, like many other organisms, are selected to avoid close inbreeding because of the fitness costs of inbreeding depression. The proximate mechanism of human inbreeding avoidance seems to be precultural, and to involve the interaction of genetic predispositions and environmental conditions. As first suggested by E. Westermarck, and supported by evidence from Israeli kibbutzim, Chinese sim-pua marriage, and much convergent ethnographic and clinical evidence, humans negatively imprint on intimate associates during a critical period (...) of early childhood.There is also much evidence that, like other social animals, humans do not seek to maximize outbreeding, but rather to maintain an optimal balance between outbreeding and inbreeding.Closeinbreeding reduces fitness through inbreeding depression, butsomeinbreeding brings the benefits of nepotism. For simple, stateless, horticultural societies, the optimal balance seems to be achieved by a combination of precultural inbreeding avoidance of relatives with anr≤·25 and cultural rules of preferential marriage with kin withr≥·25. Adjustment of the coefficient of inbreeding to other ecological settings seems to be largely cultural. An interactive model of “culture in nature” is presented, in which culture is seen as coevolving with genes to produce the maxiniization of individual inclusive fitness. (shrink)

SummaryThis paper addresses the question of what scientific realism implies and what it does not when it is articulated so as to provide the best defense against plausible philosophical alternatives. A summary is presented of “abductive” arguments for scientific realism, and of the epistemological and semantic conceptions upon which they depend. Taking these arguments to be the best current defense of realism, it is inquired what, in the sense just mentioned, realism implies and what it does not. It is concluded (...) that realism implies the strong rejection of epistemological foundationalism, a non‐Humean conception of causation and of explanation, and a causal rather than conceptual account of the unity of natural definitions. It is denied that realism implies bivalence or the existence of one true theory, one preferred vocabulary or one distinctly privileged science. It is further denied that realism implies that there are no unrecognized conventional aspects to scientific theorizing and it is denied that realism implies that scientists routinely do good experimental metaphysics. (shrink)

Confusions about the place of race in medicine result in part from a failure to recognize the plurality of race concepts. Recognition that the ordinary concept of race is not identical to the racialist concept of race makes it possible to ask whether there might be a legitimate place for the deployment of concepts of race in medical contexts. Two technical race concepts are considered. The concept of social race is the concept of a social group that is taken to (...) be a racialist race. It is apt for use in examining and addressing the medical effects of discrimination. The populationist concept of race represents race as a kind of biological population. It makes it possible to frame the question whether biological race is a factor in disease susceptibility and drug responsiveness. It is apt for use in determining whether biological race is a medically significant category. (shrink)

This paper considers the question of whether there is a human-animal or ‘anthropological difference'. It starts with a historical introduction to the project of philosophical anthropology. Section 2 explains the philosophical quest for an anthropological difference. Sections 3-4 are methodological and explain how philosophical anthropology should be pursued in my view, namely as impure conceptual analysis. The following two sections discuss two fundamental objections to the very idea of such a difference, biological continuity and Darwinist anti-essentialism. Section 7 discusses various (...) possible responses to this second objection - potentiality, normality and typicality. It ends by abandoning the idea of an essence possessed by all and only individual human beings. Instead, anthropological differences are to be sought in the realm of capacities underlying specifically human societies. The final section argues that if there is such a thing as the anthropological difference, it is connected to language. But it favours a more modest line according to which there are several anthropological differences which jointly underlie the gap separating us from our animal cousins. (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)

Historians and philosophers of science agree that Darwin had an understanding of species which led to a workable theory of their origins. To Darwin species did not differ essentially from ‘varieties’ within species, but were distinguishable in that they had developed gaps in formerly continuous morphological variation. Similar ideas can be defended today after updating them with modern population genetics. Why then, in the 1930s and 1940s, did Dobzhansky, Mayr and others argue that Darwin failed to understand species and speciation? (...) Mayr and Dobzhansky argued that reproductively isolated species were more distinct and ‘real’ than Darwin had proposed. Believing species to be inherently cohesive, Mayr inferred that speciation normally required geographic isolation, an argument that he believed, incorrectly, Darwin had failed to appreciate. Also, before the sociobiology revolution of the 1960s and 1970s, biologists often argued that traits beneficial to whole populations would spread. Reproductive isolation was thus seen as an adaptive trait to prevent disintegration of species. Finally, molecular genetic markers did not exist, and so a presumed biological function of species, reproductive isolation, seemed to delimit cryptic species better than character-based criteria like Darwin’s. Today, abundant genetic markers are available and widely used to delimit species, for example using assignment tests: genetics has replaced a Darwinian reliance on morphology for detecting gaps between species. In the 150th anniversary of The Origin of Species , we appear to be returning to more Darwinian views on species, and to a fuller appreciation of what Darwin meant. (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 distinction between a type and its tokens is a useful metaphysical distinction. In §1 it is explained what it is, and what it is not. Its importance and wide applicability in linguistics, philosophy, science and everyday life are briefly surveyed in §2. Whether types are universals is discussed in §3. §4 discusses some other suggestions for what types are, both generally and specifically. Is a type the sets of its tokens? What exactly is a word, a symphony, a species? (...) §5 asks what a token is. §6 considers the relation between types and their tokens. Do the type and all its tokens share the same properties? Must all the tokens be alike in some or all respects? §7 explains some problems for the view that types exist, and some problems for the view that they don't. §8 elucidates a distinction often confused with the type-token distinction, that between a type (or token) and an occurrence of it. It also discusses some problems that occurrences might be thought to give rise to, and one way to resolve them. (shrink)

This paper explains the metaphysical implications of the view that species are individuals (SAI). I first clarify SAI in light of the separate distinctions between individuals and classes, particulars and universals, and abstract and concrete things. I then show why the standard arguments given in defense of SAI are not compelling. Nonetheless, the ontological status of species is linked to the traditional "species problem," in that certain species concepts do entail that species are individuals. I develop the idea that species (...) names are rigid designators and show how this provides additional motivation for SAI. (shrink)

We tend to think that there are different types of biological taxa: some taxa are species, others are genera, while others are families. Linnaeus gave us his ranks in 1731. Biological theory has changed since Linnaeus's time. Nevertheless, the vast majority of biologists still assign Linnaean ranks to taxa, even though that practice is at odds with evolutionary theory and even though it causes a number of practical problems. The Linnaean ranks should be abandoned and alternative methods for displaying the (...) hierarchical relations of taxa should be adopted. (shrink)

Developmental systems theory (DST) is a wholeheartedly epigenetic approach to development, inheritance and evolution. The developmental system of an organism is the entire matrix of resources that are needed to reproduce the life cycle. The range of developmental resources that are properly described as being inherited, and which are subject to natural selection, is far wider than has traditionally been allowed. Evolution acts on this extended set of developmental resources. From a developmental systems perspective, development does not proceed according to (...) a preformed plan; what is inherited is much more than DNA; and evolution is change not only in gene frequencies, but in entire developmental systems. (shrink)

Evolutionary theory is a paradigmatic example of a well-supported scientific theory. In this chapter we consider a number of objections to evolutionary theory, and show how responding to these objections reveals aspects of the way in which scientific theories are supported by evidence. Teaching these objections can therefore serve two pedagogical aims: students can learn the right way to respond to some popular arguments against evolutionary theory, and they can learn some basic features of the structure of scientific theories and (...) evidence. (shrink)

Marc Ereshefsky argues that pluralism about species suggests that the species concept is not theoretically useful. It is to be abandoned in favor of several concrete species concepts that denote real categories. While accepting species pluralism, the present paper rejects eliminativism about the species category. It is argued that the species concept is important and that it is possible to make sense of a general species concept despite the existence of different concrete species concepts.

In this thesis I argue that we should break with the dominant Kripkean tradition concerning natural kind terms and theoretical identity. I claim that there is just no interesting connection between the metaphysics and semantics of natural kind terms, and demonstrate this by constructing a version of descriptivism that is combined with the same metaphysics – that is, a nontrivial version of essentialism – found in Kripke, but which effectively avoids all of the standard criticisms. With my version of descriptivism (...) in place, I present what I take to be the most reasonable version of metaphysical essentialism, positing only what I call 'thin' essences. I claim that thin essences are perfectly adequate to underpin scientific realism, and moreover that they are sufficient to support the version of descriptivism developed here. In effect, what I offer here is an error theory of the Kripkean tradition: Kripke is right to think that there are interesting things to say about meaning and essence, but just wrong about what those things are. Thus whilst Kripke thinks that it is possible to make discoveries about the meanings of natural kind terms, I think, rather, that we make empirical discoveries that lead to revisions in meaning. Furthermore, whilst Kripke thinks there is a dichotomy between de re and de dicto necessity, and that theoretical identities are necessary de re, I think this distinction is both misleading and inaccurate, and that the necessity of theoretical identities is neither entirely de re nor entirely de dicto. By separating and insulating questions concerning meaning from questions concerning essence I show that whilst scientific discoveries are contingent and a posteriori, the definition of scientific terms are both necessary and a priori. (shrink)

Species are central to biology, but there is currently no agreement on what the adequate species concept should be, and many have adopted a pluralist stance: different species concepts will be required for different purposes. This thesis is a multidimensional analysis of species pluralism. First I explicate how pluralism differs monism and relativism. I then consider the history of species pluralism. I argue that we must re-frame the species problem, and that re-evaluating Aristotle's role in the histories of systematics can (...) shed light on pluralism. Next I consider different forms of pluralism: evolutionary and extra-evolutionary species pluralism, which differ in their stance on evolutionary theory. I show that pluralism is more than a debate about the species category, but a debate about which concepts are legitimate and a claim about how they interact with one another. Following that, I consider what sort of ontology is required for different forms of species pluralism. I argue that pluralists who deny the unity of biology will require a further plurality of frameworks, while those that ground their pluralism in evolution need only one framework. Finally, I consider what pluralism means for biological practice. I argue that species concepts are tools, and reflect on how pluralism can illuminate the way systematists approach the discovery of new species of yeast. Pluralism can make sense of the way species concepts are used, and can be developed to aid researchers in thinking about how to use the right tools for the right jobs. (shrink)

According to the species-as-individuals thesis(hereafter S-A-I), species are cohesive entities. Barker and Wilson recently pointed out that the type of cohesion exhibited by species is fundamentally different from that of organisms (paradigmatic individuals), suggesting that species are homeostatic property cluster kinds. In this article, I propose a shift in how to approach cohesion in the context of S-A-I: instead of analyzing the different types of cohesion and questioning whether species have them, I focus on the role played by cohesion in (...) the identity of individuals. This shift allows us to recognize why cohesion matters to S-A-I, as well as to reconceive the analogy between species and organisms (paradigmatic individuals), and also allows us to highlight the context sensitivity of both ‘‘cohesion’’ and ‘‘individuals.’’ From this perspective, I identify two problems in Barker and Wilson’s argumentation. Firstly, the authors fail to recognize that species are individuals even if they do not have the same type of cohesion that organisms have. Secondly, their argument relies on a misinterpretation of S-A-I. I conclude that species cohesion is still best framed as a feature of species individuality rather than a feature of species as homeostatic property cluster kinds. The arguments presented here contribute to the re-articulation and reevaluation of S-A-I in the face of contemporary discussions. (shrink)

Pluralist and eliminativist positions have proliferated within both science and philosophy of science in recent decades. This paper asks the question why this shift of thinking has occurred, and where it is leading us. We provide an explanation which, if correct, entails that we should expect pluralism and eliminativism to transform other debates currently unaffected, and for good reasons. We then consider the question under what circumstances eliminativism will be appropriate, arguing that it depends not only on the term in (...) question, but also on the context of discussion and details of the debate at hand. The resultant selective eliminativism is an appealing compromise for various ‘pluralists’ and ‘eliminativists’ who are currently locking horns. (shrink)

Atoms, molecules, organisms distinguish layers of reality because of the causal links that govern their behavior, both horizontally (atom-atom, molecule-molecule, organism-organism) and vertically (atom-molecule-organism). This is the first intuition of the theory of levels. Even if the further development of the theory will require imposing a number of qualifications to this initial intuition, the idea of a series of entities organized on different levels of complexity will prove correct. Living systems as well as social systems and the human mind present (...) features remarkably different from those characterizing non-living, simple physical and chemical systems. We propose that super-complexity requires at least four different categorical frameworks, provided by the theories of levels of reality, chronotopoids, (generalized) interactions, and anticipation. (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)

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)

The term “genetic load” first emerged in a paper written in 1950 by the geneticist H. Muller. It is a mathematical model based on biological, social, political and ethical arguments describing the dramatic accumulation of disadvantageous mutations in human populations that will occur in modern societies if eugenic measures are not taken. The model describes how the combined actions of medical and social progress will supposedly impede natural selection and make genes of inferior quality likely to spread across populations – (...) a process which in fine loads their progress. Genetic load is based on optimal fitness and emerges from a “typological view” of evolution. This model of evolution had previously, however, been invalidated by Robert Wright and Theodosius Dobzhansky who, as early as 1946, showed that polymorphism was the rule in natural populations. The blooming and persistence of the concept of genetic load, after its theoretical basis had already expired, are a historical puzzle. This persistence reveals the intricacy of science and policy-making in eugenic matters. The Canguilhemian concept of ‘scientific ideology’ is used along with the concept of ‘immutable mobile’ and compared with the concept of ‘co-production’, to provide complementary perspectives on this complex phenomenon. (shrink)

Many of the existing ethical analyses of genetic engineering technologies (GET) focus on how they can be used to enhance individuals—to improve individual well-being, health and cognition. There is a gap in the current literature about the specific ways enhancement technologies could be used to improve our populations and species, viewed as a whole. In this paper, I explore how GET may be used to enhance the species through improvements in the gene pool. I argue one aspect of the species (...) that may be desirable to enhance is ‘persistence’ or long-term viability. I then look at some of the ways in which GET could be used to improve human persistence and argue that the use of GET to secure benefits for individuals may compromise persistence. This suggests conflicts between uses of GET to enhance individuals and uses to promote the persistence of the species may occur. As GET are further developed, the likelihood that these conflicts will actually arise, and how we should resolve them if they do, will need to be considered. (shrink)

Recent discussions in the philosophy of psychology have examined the use and legitimacy of such notions as “representation”, “content”, “computation”, and “inference” within a scientific psychology. While the resulting assessments have varied widely, ranging from outright rejection of some or all of these notions to full vindication of their use, there has been notable agreement on the considerations deemed relevant for making an assessment. The answer to the question of whether the notion of, say, representational content may be admitted into (...) a scientific psychology has often been made to hinge upon whether the notion can be squared with our “ordinary” or “folk” style of psychological explanation, with its alleged commitment to the idiom of beliefs and desires. In this article, I proceed the other way around, starting with experimental psychology itself and asking whether such notions as the above play a legitimate role within a particular area of contemporary theory, the psychology of perception. My conclusion will be that especially the first three have a legitimate place in theories of perception, albeit one that differs from that ascribed to them in a significant portion of the philosophical literature. Along the way I develop a notion of noncognitive functional analysis, which separates the notion of contentful perceptual processing and perceptual representation from cognitive or conceptual content. (This paper has been reprinted, with stylistic revisions, in Perception and Cognition, Essays in the Philosophy of Psychology, Oxford, Clarendon Press, 2009, pp. 50-87.). (shrink)

The Linnaean system of classification is a threefold system of theoretical assumptions, sorting rules, and rules of nomenclature. Over time, that system has lost its theoretical assumptions as well as its sorting rules. Cladistic revisions have left it less and less Linnaean. And what remains of the system is flawed on pragmatic grounds. Taking all of this into account, it is time to consider alternative systems of classification.

The variation and selection form of explanationcan be prescinded from the evolutionary biologyhome ground in which it was discovered and forwhich it has been most developed. When this isdone, variation and selection explanations arefound to have potential application to a widerange of phenomena, far beyond the classicalbiological ground and the contemporaryextensions into epistemological domains. Itappears as the form of explanation most suitedto phenomena of fit. It is also found toparticipate in multiple interestingrelationships with other forms of explanation. We proceed with (...) an examination of multiplekinds of phenomena, interrelationships withother members of the family of forms ofexplanation, and some novel applications evenwithin the home ground of evolutionary biology. (shrink)

The latter half of the twentieth century has been marked by debates in evolutionary biology over the relative significance of natural selection and random drift: the so-called “neutralist/selectionist” debates. Yet John Beatty has argued that it is difficult, if not impossible, to distinguish the concept of random drift from the concept of natural selection, a claim that has been accepted by many philosophers of biology. If this claim is correct, then the neutralist/selectionist debates seem at best futile, and at worst, (...) meaningless. I reexamine the issues that Beatty raises, and argue that random drift and natural selection, conceived as processes, can be distinguished from one another. (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)

The species problem is the longstanding puzzle regarding the nature of species. This paper aims to describe how biologists experience little communication breakdown when they have different conceptions of species. For this purpose, I analyze two debates on species and speciation between Guy Bush and Jerry Coyne & H. Allen Orr. Although they have radically different ideas on species, they experience little communication difficulty. I will argue that this is because they implicitly agreed on the referent of the group of (...) organisms being addressed and possible causal factors of the speciation process. This analysis confirms a leading account in the general philosophy of science on the way in which scientists avoid the incommensurability threat. (shrink)

Paul Thompson, John Beatty, and Elisabeth Lloyd argue that attempts to resolve certain conceptual issues within evolutionary biology have failed because of a general adherence to the received view of scientific theories. They maintain that such issues can be clarified and resolved when one adopts a semantic approach to theories. In this paper, I argue that such conceptual issues are just as problematic on a semantic approach. Such issues arise from the complexity involved in providing formal accounts of theoretical laws (...) and scientific explanations. That complexity is due to empirical and pragmatic considerations, not one's adherence to a particular formal approach to theories. This analysis raises a broader question. How can any formal account properly represent the complex nature of empirical phenomena? (shrink)

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 concept of nature in Western thought has been informed by the assumption of a categorical distinction between natural and artificial entities, which goes back to John Stuart Mill or even Aristotle. Such a way of articulating the natural/artificial distinction has proven unfit for conservation purposes mainly because of the extent and the pervasiveness of human activities that would leave no nature left to be conserved, and alternative views have been advanced. In this contribution, after arguing for the importance of (...) the concept of naturalness as a guide for conservation, I will try to provide an account of the natural/artificial distinction suited to contemporary conservation framing. Focusing on a particular kind of objects that I suggest to name “environmental objects”, I propose and defend the view of “naturalness as independence” according to which the more or less an environmental object's identity conditions and survival depend on human intervention, the more or less that object is artificial or natural, respectively. According to this view, conserving environmental objects will equate to maintaining or improving their naturalness or even originating artificial objects that may become new natural objects. This view has the advantage, on the one hand, of providing a rationale for a distinction which is not only part of how people think, but also pervasive in conservation practices and policies and, on the other hand, of accounting for the global pervasiveness of human intervention in the so-called natural world. (shrink)

Recent work on children’s inferences concerning biological and chemical categories has suggested that children (and perhaps adults) are essentialists— a view known as psychological essentialism. I distinguish three varieties of psychological essentialism and investigate the ways in which essentialism explains the inferences for which it is supposed to account. Essentialism succeeds in explaining the inferences, I argue, because it attributes to the child belief in causal laws connecting category membership and the possession of certain characteristic appearances and behavior. This suggests (...) that the data will be equally well explained by a non-essentialist hypothesis that attributes belief in the appropriate causal laws to the child, but makes no claim as to whether or not the child represents essences. I provide several reasons to think that this non-essentialist hypothesis is in fact superior to any version of the essentialist hypothesis. (shrink)

As a significant extension of our previous calculus of logical differentials and moving logic, we propose here a mathematical diagram for specifying the emergence of novelty, through the construction of some “differentials” related to cohomological computations. Later we intend to examine how to use these “differentials” in the analysis of anticipation or evolution schemes. This proposal is given as a consequence of our comments on the Ehresmann–Vanbremeersch’s work on memory evolutive systems, from the two points of view which are characterization (...) of life and use of categorical modeling. It would not be possible to conceive of the “differentials” outside the frame of a MES. Furthermore, we hope that this diagram will be useful to exhibit the “emergence of sense” in discourses, and this idea is supported here by a brief examination of how a discourse could be seen as a living system. (shrink)

After having reconstructed a minimal biological characterisation of species, we endorse an “empirical approach” based on the idea that it is the peculiar evolutionary history of the species at issue—its peculiar origination process, its peculiar metapopulation structure and the peculiar mixture and strength of homeostatic processes vis à vis heterostatic ones—that determines species’ identity at a time and through time. We then explore the consequences of the acceptance of the empirical approach in settling the individuals versus kinds dispute. In particular, (...) while conceptual arguments have been proposed to show that species can be equally treated as individuals and kinds because mereology’s and set-theory’s languages are inter-translatable, we advance instead a causal argument to sustain the claim that each species is both a kind and an individual. (shrink)