Is it possible to get by with just one ontological category? We evaluate L.A. Paul's attempt to do so: the mereological bundle theory. The upshot is that Paul's attempt to construct a one category ontology may be challenged with some of her own arguments. In the positive part of the paper we outline a two category ontology with property universals and kind universals. We will also examine Paul's arguments against a version of universal bundle theory that takes spatiotemporal co-location instead (...) of compresence or coinstantiation as the feature by which we can identify genuine bundles. We compare this novel theory, bundle theory with kinds, and Paul's mereological bundle theory and apply them to a case study concerning entangled fermions and co-located bosons. (shrink)

The account of natural kinds as stable property clusters is premised on the possibility of separating the epistemic value of natural kinds from their underlying metaphysics. On that account, the co-instantiation of any sub-cluster of the properties associated with a given natural kind raises the probability of the co-instantiation of the rest, and this clustering of property instantiation is invariant under all relevant counterfactual perturbations. We argue that it is not possible to evaluate the stability of a cluster of properties (...) without taking stock of the metaphysical picture used to account for that stability. Thus, even on the stable property cluster account, the epistemic value of natural kinds remains partly grounded in their metaphysical status. (shrink)

This volume consists of the first of the John Dewey Lectures delivered under the auspices of Columbia University's Philosophy Department as well as other essays by the author. Intended to clarify the meaning of the philosophical doctrines propounded by Professor Quine in 'Word and Objects', the essays included herein both support and expand those doctrines.

'To think often, and never to retain it so much as one moment, is a very useless sort of thinking' In An Essay concerning Human Understanding, John Locke sets out his theory of knowledge and how we acquire it. Eschewing doctrines of innate principles and ideas, Locke shows how all our ideas, even the most abstract and complex, are grounded in human experience and attained by sensation of external things or reflection upon our own mental activities. A thorough examination of (...) the communication of ideas through language and the conventions of taking words as signs of ideas paves the way for his penetrating critique of the limitations of ideas and the extent of our knowledge of ourselves, the world, God, and morals. Locke's masterpiece laid the foundation of British empiricism and is of enduring interest to anyone exploring the development of philosophical thought. This sensitive abridgement uses P. H. Nidditch's authoritative text, and together with an illuminating introduction and other features, makes Locke's arguments more accessible. (shrink)

Eliminative materialism is the thesis that our common-sense conception of psychological phenomena constitutes a radically false theory, a theory so fundamentally defective that both the principles and the ontology of that theory will eventually be displaced, rather than smoothly reduced, by completed neuroscience. Our mutual understanding and even our introspection may then be reconstituted within the conceptual framework of completed neuroscience, a theory we may expect to be more powerful by far than the common-sense psychology it displaces, and more substantially (...) integrated within physical science generally. My purpose in this paper is to explore these projections, especially as they bear on (1) the principal elements of common-sense psychology: the propositional attitudes (beliefs, desires, etc.), and (2) the conception of rationality in which these elements figure. (shrink)

There are many ways of construing the claim that some categories are more “natural" than others. One can ask whether a system of categories is innate or acquired by learning, whether it pertains to a natural phenomenon or to a social institution, whether it is lexicalized in natural language or requires a compound linguistic expression. This renders suspect any univocal answer to this question in any particular case. Yet another question one can ask, which some authors take to have a (...) bearing on the issue of the naturalness of categories, is whether a system of categories constitutes a unique way of organizing a particular set of entities or phenomena, or whether there are other legitimate classification schemes that can coexist with it. Another way of putting this is by asking whether systems of categories can cut across one another, and if so, under what circumstances. Some philosophers have claimed that crosscutting systems of categories cannot exist as genuine natural kinds. This paper examines that claim and puts forward some counterexamples, concluding that this notion of natural kind is not in tune with scientific classification and ought to be rejected in favor of an alternative. (shrink)

E. J. Lowe, a prominent figure in contemporary metaphysics, sets out and defends his theory of what there is. His four-category ontology is a metaphysical system which recognizes four fundamental categories of beings: substantial and non-substantial particulars and substantial and non-substantial universals. Lowe argues that this system has an explanatory power which is unrivalled by more parsimonious theories and that this counts decisively in its favour. He shows that it provides a powerful explanatory framework for a unified account of causation, (...) dispositions, natural laws, natural necessity and many other related matters, thus constituting a full metaphysical foundation for natural science. (shrink)

Scientific Essentialism defends the view that the fundamental laws of nature depend on the essential properties of the things on which they are said to operate, and are therefore not independent of them. These laws are not imposed upon the world by God, the forces of nature or anything else, but rather are immanent in the world. Ellis argues that ours is a dynamic world consisting of more or less transient objects which are constantly interacting with each other, and whose (...) identities depend on their roles in these processes. Natural objects must behave as they do, because to do otherwise would be contrary to their natures. The laws of nature are, therefore, metaphysically necessary, and consequently, there are necessary connections between events. Brian Ellis calls for the rejection of the theory of Humean Supervenience and an implementation of a new kind of realism in philosophical analysis. (shrink)

According to the received tradition, the language used to to refer to natural kinds in scientific discourse remains stable even as theories about these kinds are refined. In this illuminating book, Joseph LaPorte argues that scientists do not discover that sentences about natural kinds, like 'Whales are mammals, not fish', are true rather than false. Instead, scientists find that these sentences were vague in the language of earlier speakers and they refine the meanings of the relevant natural-kind terms to make (...) the sentences true. Hence, scientists change the meaning of these terms, This conclusions prompts LaPorte to examine the consequences of this change in meaning for the issue of incommensurability and for the progress of science. This book will appeal to students and professional in the philosophy of science, the philosophy of biology and the philosophy of language. (shrink)

In this important study D. M. Armstrong offers a comprehensive system of analytical metaphysics that synthesises but also develops his thinking over the last twenty years. Armstrong's analysis, which acknowledges the 'logical atomism' of Russell and Wittgenstein, makes facts the fundamental constituents of the world, examining properties, relations, numbers, classes, possibility and necessity, dispositions, causes and laws. All these, it is argued, find their place and can be understood inside a scheme of states of affairs. This is a comprehensive and (...) rigorously this-worldly account of the most general features of reality, argued from a distinctive philosophical perspective, and it will appeal to a wide readership in analytical philosophy. (shrink)

Both realist and anti-realist accounts of natural kinds possess prima facie virtues: realists can straightforwardly make sense of the apparent objectivity of the natural kinds, and anti-realists, their knowability. This paper formulates a properly anti-realist account designed to capture both merits. In particular, it recommends understanding natural kinds as ‘categorical bottlenecks,’ those categories that not only best serve us, with our idiosyncratic aims and cognitive capacities, but also those of a wide range of alternative agents. By endorsing an ultimately subjective (...) categorical principle, this view sidesteps epistemological difficulties facing realist views. Yet, it nevertheless identifies natural kinds that are fairly, though not completely, stance-independent or objective. (shrink)

Philosophers have long been interested in a series of interrelated questions about natural kinds. What are they? What role do they play in science and metaphysics? How do they contribute to our epistemic projects? What categories count as natural kinds? And so on. Owing, perhaps, to different starting points and emphases, we now have at hand a variety of conceptions of natural kinds—some apparently better suited than others to accommodate a particular sort of inquiry. Even if coherent, this situation isn’t (...) ideal. My goal in this article is to begin to articulate a more general account of ‘natural kind phenomena’. While I do not claim that this account should satisfy everyone—it is built around a certain conception of the epistemic role of kinds and has an obvious pragmatic flavour—I believe that it has the resources to go further than extant alternatives, in particular the homeostatic property cluster view of kinds. (shrink)

Over recent years, the psychology of concepts has been rejuvenated by new work on prototypes, inventive ideas on causal cognition, the development of neo-empiricist theories of concepts, and the inputs of the budding neuropsychology of concepts. But our empirical knowledge about concepts has yet to be organized in a coherent framework. -/- In Doing without Concepts, Edouard Machery argues that the dominant psychological theories of concepts fail to provide such a framework and that drastic conceptual changes are required to make (...) sense of the research on concepts in psychology and neuropsychology. Machery shows that the class of concepts divides into several distinct kinds that have little in common with one another and that for this very reason, it is a mistake to attempt to encompass all known phenomena within a single theory of concepts. In brief, concepts are not a natural kind. Machery concludes that the theoretical notion of concept should be eliminated from the theoretical apparatus of contemporary psychology and should be replaced with theoretical notions that are more appropriate for fulfilling psychologists' goals. The notion of concept has encouraged psychologists to believe that a single theory of concepts could be developed, leading to useless theoretical controversies between the dominant paradigms of concepts. Keeping this notion would slow down, and maybe prevent, the development of a more adequate classification and would overshadow the theoretical and empirical issues that are raised by this more adequate classification. Anyone interested in cognitive science's emerging view of the mind will find Machery's provocative ideas of interest. (shrink)

Recent work on Natural Kind Essentialism has taken a deflationary turn. The assumptions about the grounds of essentialist truths concerning natural kinds familiar from the Kripke-Putnam framework are now considered questionable. The source of the problem, however, has not been sufficiently explicated. The paper focuses on the Twin Earth scenario, and it will be demonstrated that the essentialist principle at its core (which I call IDENT)—that necessarily, a sample of a chemical substance, A, is of the same kind as another (...) sample, B, if and only if A and B have the same microstructure—must be re-evaluated. The Twin Earth scenario also assumes the falsity of another essentialist principle (which I call INST): necessarily, there is a 1:1 correlation between (all of ) the chemical properties of a chemical substance and the microstructure of that substance. This assumption will be questioned, and it will be argued that, in fact, the best strategy for defending IDENT is to establish INST. The prospects for Natural Kind Essentialism and microstructural essentialism regarding chemical substances will be assessed with reference to recent work in the philosophy of chemistry. Finally, a weakened form of INST will be presented. (shrink)

This edited volume of 13 new essays aims to turn past discussions of natural kinds on their head. Instead of presenting a metaphysical view of kinds based largely on an unempirical vantage point, it pursues questions of kindedness which take the use of kinds and activities of kinding in practice as significant in the articulation of them as kinds. The book brings philosophical study of current and historical episodes and case studies from various scientific disciplines to bear on natural kinds (...) as traditionally conceived of within metaphysics. Focusing on these practices reveals the different knowledge-producing activities of kinding and processes involved in natural kind use, generation, and discovery. -/- Specialists in their field, the esteemed group of contributors use diverse empirically responsive approaches to explore the nature of kindhood. This groundbreaking volume presents detailed case studies that exemplify kinding in use. Newly written for this volume, each chapter engages with the activities of kinding across a variety of disciplines. Chapter topics include the nature of kinds, kindhood, kinding, and kind-making in linguistics, chemical classification, neuroscience, gene and protein classification, colour theory in applied mathematics, homology in comparative biology, sex and gender identity theory, memory research, race, extended cognition, symbolic algebra, cartography, and geographic information science. -/- The volume seeks to open up an as-yet unexplored area within the emerging field of philosophy of science in practice, and constitutes a valuable addition to the disciplines of philosophy and history of science, technology, engineering, and mathematics. -/- Contributions from a diverse group of established and junior scholars in the fields of Philosophy and History and Philosophy of Science including Hasok Chang, Jordi Cat, Sally Haslanger, Joyce C. Havstad, Catherine Kendig, Bernhard Nickel, Josipa Petrunic, Samuli Pöyhönen, Thomas A. C. Reydon, Quayshawn Spencer, Jackie Sullivan, Michael Wheeler, and Rasmus Grønfeldt Winther. (shrink)

This chapter discusses the distinction between natural kinds and natural properties. Some theorists deny the distinction, and claim that natural kinds can be identified with properties. For example, natural kinds might be understood as the perfectly natural properties, reducible to properties or the extensions of properties. Alternatively, one might argue that natural kinds and natural properties are distinct and that natural kinds could be considered as a sui generis type of entity. For example, one might hold that natural kinds require (...) a distinct kind of universal, substantival universal, or sortal. Alternatively, one might claim that properties themselves form natural kind groupings, in virtue of causal mechanisms. This chapter argues that classification into natural kinds can reflect real differences between natural groups, without the supplementary ontological distinction between properties and kinds. -/- . (shrink)

Some scientific categories seem to correspond to genuine features of the world and are indispensable for successful science in some domain; in short, they are natural kinds. This book gives a general account of what it is to be a natural kind and puts the account to work illuminating numerous specific examples.

In this paper I investigate the relationship between vernacular kind terms and specialist scientific vocabularies. Elsewhere I have developed a defence of realism about the chemical elements as natural kinds. This defence depends on identifying the epistemic interests and theoretical conception of the elements that have suffused chemistry since the mid-eighteenth century. Because of this dependence, it is a discipline-specific defence, and would seem to entail important concessions to pluralism about natural kinds. I argue that making this kind of concession (...) does not imply that vernacular kind terms have independent application conditions. Nor does it preclude us saying that chemists, with their particular epistemic interests, have discovered the underlying nature of water, the stuff that is named and thought about in accordance with the practical interests of everyday life. There are limits to pluralism. (shrink)

Social constructivists maintain that we invent the properties of the world rather than discover them. Is reality constructed by our own activity? Or, more provocatively, are scientific facts--is everything --constructed? Social Constructivism and the Philosophy of Science is a clear assessment of this critical and increasingly important debate. Andre Kukla presents a comprehensive discussion of the philosophical issues involved and analyzes the strengths and weaknesses of a range of constructivist arguments, illustrating the divide between the sociology and the philosophy of (...) science through examples as varied as laboratory science, time, and criminality. He argues that current philosophical objections to constructivism are drastically inconclusive, while offering and developing new objections. Throughout, Kukla distinguishes between the social causes of scientific beliefs and the view that all ascertainable facts are constructed. (shrink)

Jerry Fodor presents a new development of his famous Language of Thought hypothesis, which has since the 1970s been at the centre of interdisciplinary debate about how the mind works. Fodor defends and extends the groundbreaking idea that thinking is couched in a symbolic system realized in the brain. This idea is central to the representational theory of mind which Fodor has established as a key reference point in modern philosophy, psychology, and cognitive science. The foundation stone of our present (...) cognitive science is Turing's suggestion that cognitive processes are not associations but computations; and computation requires a language of thought. So the latest on the Language of Thought hypothesis, from its progenitor, promises to be a landmark in the study of the mind. LOT 2 offers a more cogent presentation and a fuller explication of Fodor 's distinctive account of the mind, with various intriguing new features. The central role of compositionality in the representational theory of mind is revealed: most of what we know about concepts follows from the compositionality of thoughts. Fodor shows the necessity of a referentialist account of the content of intentional states, and of an atomistic account of the individuation of concepts. Not least among the new developments is Fodor 's identification and persecution of pragmatism as the leading source of error in the study of the mind today. LOT 2 sees Fodor advance undaunted towards the ultimate goal of a theory of the cognitive mind, and in particular a theory of the intentionality of cognition. No one who works on the mind can ignore Fodor 's views, expressed in the coruscating and provocative style which has delighted and disconcerted countless readers over the years. (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)

It is common to defend the Homeostatic Property Cluster ( HPC ) view as a third way between conventionalism and essentialism about natural kinds ( Boyd , 1989, 1991, 1997, 1999; Griffiths , 1997, 1999; Keil , 2003; Kornblith , 1993; Wilson , 1999, 2005; Wilson , Barker , & Brigandt , forthcoming ). According to the HPC view, property clusters are not merely conventionally clustered together; the co-occurrence of properties in the cluster is sustained by a similarity generating ( (...) or homeostatic ) mechanism . I argue that conventional elements are involved partly but ineliminably in deciding which mechanisms define kinds , for deciding when two mechanisms are mechanisms of the same type, and for deciding where one particular mechanism ends and another begins. This intrusion of conventional perspective into the idea of a mechanism raises doubts as to whether the HPC view is sufficiently free of conventional elements to serve as an objective arbiter in scientific disputes about what the kinds of the special sciences should be. (shrink)

This paper examines the phenomenon of ‘interactive kinds’ first identified by Ian Hacking. An interactive kind is one that is created or significantly modified once a concept of it has been formulated and acted upon in certain ways. Interactive kinds may also ‘loop back’ to influence our concepts and classifications. According to Hacking, interactive kinds are found exclusively in the human domain. After providing a general account of interactive kinds and outlining their philosophical significance, I argue that they are not (...) confined to the human realm, but that they can also occur elsewhere. Hence, I conclude by arguing that interactive kinds pose a challenge to scientific realism about kinds by making it difficult to make a distinction between real and non-real kinds. (shrink)

Microstructuralism in the philosophy of chemistry is the thesis that chemical kinds can be individuated in terms of their microstructural properties (Hendry in Philos Sci 73:864–875, 2006 ). Elements provide paradigmatic examples, since the atomic number should suffice to individuate the kind. In theory, Microstructuralism should also characterise higher-level chemical kinds such as molecules, compounds, and macromolecules based on their constituent atomic properties. In this paper, several microstructural theses are distinguished. An analysis of macromolecules such as moonlighting proteins suggests that (...) all the forms of microstructuralism cannot accommodate them. (shrink)

Traditionally, species have been treated as classes. In fact they may be considered individuals. The logical term “individual” has been confused with a biological synonym for “organism.” If species are individuals, then: 1) their names are proper, 2) there cannot be instances of them, 3) they do not have defining properties, 4) their constituent organisms are parts, not members. “ Species " may be defined as the most extensive units in the natural economy such that reproductive competition occurs among their (...) parts. Species are to evolutionary theory as firms are to economic theory: this analogy resolves many issues, such as the problems of “reality” and the ontological status of nomenclatorial types. (shrink)

In this article I assess the problems and prospects of a microstructural approach to chemical substances. Saul Kripke and Hilary Putnam famously claimed that to be gold is to have atomic number 79 and to be water is to be H2O. I relate the first claim to the concept of element in the history of chemistry, arguing that the reference of element names is determined by atomic number. Compounds are more difficult: water is so complex and heterogeneous at the molecular (...) level that `water is H2O’ seems false under some interpretations. I sketch a response to this problem. (shrink)

With this manifesto, John Dupré systematically attacks the ideal of scientific unity by showing how its underlying assumptions are at odds with the central conclusions of science itself.

This highly acclaimed book is a major contribution to the philosophy of language as well as a systematic interpretation of Frege, indisputably the father of ...

Standard biological and philosophical treatments assume that dramatic genotypic or phenotypic change constitutes instantaneous speciation, and that barring such saltation, speciation is gradual evolutionary change in individual properties. Both propositions appear to be incongruent with standard theoretical perspectives on species themselves, since these perspectives are (a) non-pheneticist, and (b) tend to disregard intermediate cases. After reviewing certain key elements of such perspectives, it is proposed that species-membership is mediated by membership in a population. Species-membership depends, therefore, not on intrinsic characteristics (...) of an organism, but on relationship of an organism to others. A new definition of speciation is proposed in the spirit of this proposal. This definition implies that dramatic change is neither necessary nor sufficient for speciation. It also implies, surprisingly, that an organism can change species during its lifetime. (shrink)

Required reading at more than 100 colleges and universities throughout North America.

In The Origin of Species (1859) Darwin challenged many of the most deeply-held beliefs of the Western world. Arguing for a material, not divine, origin of species, he showed that new species are achieved by "natural selection." The Origin communicates the enthusiasm of original thinking in an open, descriptive style, and Darwin's emphasis on the value of diversity speaks more strongly now than ever. As well as a stimulating introduction and detailed notes, this edition offers a register of the many (...) writers referred to by Darwin in the text. (shrink)

Jaegwon Kim is one of the most preeminent and most influential contributors to the philosophy of mind and metaphysics. This collection of essays presents the core of his work on supervenience and mind with two sets of postscripts especially written for the book. The essays focus on such issues as the nature of causation and events, what dependency relations other than causal relations connect facts and events, the analysis of supervenience, and the mind-body problem. A central problem in the philosophy (...) of mind is the problem of explaining how the mind can causally influence bodily processes. Professor Kim explores this problem in detail, criticizes the nonreductionist solution of it, and offers a modified reductionist solution of his own. Both professional philosophers and their graduate students will find this an invaluable collection. (shrink)

Especially troublesome in this dispute is the status of the natural sciences, and this is where Hacking finds some of his most telling cases, from the conflict ...

The examination of the notion of science from a sociological perspective has begun to transform the attitudes to science traditionally upheld by historians and philosophers.

This is a study of a crucial and controversial topic in metaphysics and the philosophy of science: the status of the laws of nature. D. M. Armstrong works out clearly and in comprehensive detail a largely original view that laws are relations between properties or universals. The theory is continuous with the views on universals and more generally with the scientific realism that Professor Armstrong has advanced in earlier publications. He begins here by mounting an attack on the orthodox and (...) sceptical view deriving from Hume that laws assert no more than a regularity of coincidence between instances of properties. In doing so he presents what may become the definitive statement of the case against this position. Professor Armstrong then goes on to establish his own theory in a systematic manner defending it against the most likely objections, and extending both it and the related theory of universals to cover functional and statistical laws. This treatment of the subject is refreshingly concise and vivid: it will both stimulate vigorous professional debate and make an excellent student text. (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)

Natural kinds are often contrasted with other kinds of scientific kinds, especially functional kinds, because of a presumed categorical difference in explanatory value: supposedly, natural kinds can ground explanations, while other kinds of kinds cannot. I argue against this view of natural kinds by examining a particular type of explanation—mechanistic explanation—and showing that functional kinds do the same work there as traditionally recognized natural kinds are supposed to do in “standard” scientific explanations. Breaking down this categorical distinction between traditional natural (...) kinds and other kinds of kinds, I argue, delivers two goods: It provides us with a view of natural kindhood that does justice to the epistemic roles of kinds in scientific explanations. And it allows us to solve a problem that HPC theory, currently one of the more popular accounts of natural kindhood, confronts. (shrink)

Different chemical species are often cited as paradigm examples of structurally delimited natural kinds. While classificatory monism may thus seem plausible for simple molecules, it looks less attractive for complex biological macromolecules. I focus on the case of proteins that are most plausibly individuated by their functions. Is there a single, objective count of proteins? I argue that the vagaries of function individuation infect protein classification. We should be pluralists about macromolecular classification.

A common presupposition in the concepts literature is that concepts constitute a sin- gular natural kind. If, on the contrary, concepts split into more than one kind, this literature needs to be recast in terms of other kinds of mental representation. We offer two new arguments that concepts, in fact, divide into different kinds: (a) concepts split because different kinds of mental representation, processed independently, must be posited to explain different sets of relevant phenomena; (b) concepts split because different kinds (...) of mental representation, processed independently, must be posited to explain responses to different kinds of category. Whether these arguments are sound remains an open empirical question, to be resolved by future empirical and theoretical work. (shrink)

The historian Raphael Falk has described the gene as a ‘concept in tension’ (Falk 2000) – an idea pulled this way and that by the differing demands of different kinds of biological work. Several authors have suggested that in the light of contemporary molecular biology ‘gene’ is no more than a handy term which acquires a specific meaning only in a specific scientific context in which it occurs. Hence the best way to answer the question ‘what is a gene’, and (...) the only way to provide a truly philosophical answer to that question is to outline the diversity of conceptions of the gene and the reasons for this diversity. In this essay we draw on the extensive literature in the history of biology to explain how the concept has changed over time in response to the changing demands of the biosciences . Finally, we outline some of the conceptions of the gene current today. The seeds of change are implicit in many of those current conceptions and the future of the gene concept looks set to be at as turbulent as the past. (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)