We articulate a view of natural kinds as complex universals. We do not attempt to argue for the existence of universals. Instead, we argue that, given the existence of universals, and of natural kinds, the latter can be understood in terms of the former, and that this provides a rich, flexible framework within which to discuss issues of indeterminacy, essentialism, induction, and reduction. Along the way, we develop a 'problem of the many' for universals.

A lot of philosophers engage in debates about what claims are “metaphysically necessary”, and a lot more assume with little argument that some classes of claims have the status of “metaphysical necessity”. I think we can usefully replace questions about metaphysical necessity with five other questions which each capture some of what people may have had in mind when talking about metaphysical necessity. This paper explains these five other questions, and then discusses the question “how much of metaphysics is metaphysically (...) necessary?”, and each of its five replacements. (shrink)

Lewis's notion of a "natural" property has proved divisive: some have taken to the notion with enthusiasm, while others have been sceptical. However, it is far from obvious what the enthusiasts and the sceptics are disagreeing about. This paper attempts to articulate what is at stake in this debate.

Are there any bona fide boundaries, i.e., boundaries that carve at the joints? Or is any boundary —hence any object—the result of a fiat articulation reflecting our cognitive biases and our so-cial practices and conventions? Does the choice between these two options amount to a choice between realism and wholesome relativism?

Ellis argues that certain essential properties of objects in the world not only determine the nature of these objects but also how they will behave in any situation. In this paper I will critique Ellis's essentialism from the perspective of the philosophy of chemistry, arguing that our current knowledge of chemistry in fact does not lend itself to essentialist interpretations and that this seriously undercuts Ellis's project. In particular I will criticize two key distinctions Ellis draws between internal vs. external (...) properties and essential vs. accidental properties, showing that at the chemical level such distinctions are insupportable. If essential properties only exist at the level of sub-atomic physics, then Ellis's hopes that essentialism will provide a theoretical basis for a philosophy of chemistry are at best hopes for a very distant future, since the argument that chemical structure and dynamics can be explained at the quantum level derived is purely from analogy to much simpler systems than those chemists actually study. This suggests that we have very little scientific evidence that scientific essentialism is a viable ontology. †To contact the author, please write to: Department of Philosophy, University of Notre Dame, Notre Dame, IN 46556; e-mail: [email protected]. (shrink)

In this paper I try to make as much sense aspossible of, first, the extensive philosophicalliterature concerned with the status of `Wateris H2O' and, second, the implications ofPutnam's invention of Twin Earth, anotherpossible world stipulated to be just like Earth, except that water is XYZ, notH2O.

This paper challenges the Kripkean interpretation of a posteriori necessities. It will be demonstrated, by an analysis of classic examples, that the modal content of supposed a posteriori necessities is more complicated than the Kripkean line suggests. We will see that further research is needed concerning the a priori principles underlying all a posteriori necessities. In the course of this analysis it will emerge that the modal content of a posteriori necessities can be best described in terms of a Finean (...) conception of modality – by giving essences priority over modality. The upshot of this is that we might be able to establish the necessity of certain supposed a posteriori necessities by a priori means. (shrink)

One type of deflationism about metaphysical modality suggests that it can be analysed strictly in terms of linguistic or conceptual content and that there is nothing particularly metaphysical about modality. Scott Soames is explicitly opposed to this trend. However, a detailed study of Soames’s own account of modality reveals that it has striking similarities with the deflationary account. In this paper I will compare Soames’s account of a posteriori necessities concerning natural kinds with the deflationary one, specifically Alan Sidelle’s account, (...) and suggest that Soames’s account is vulnerable to the deflationist’s critique. Furthermore, I conjecture that both the deflationary account and Soames’s account fail to fully explicate the metaphysical content of a posteriori necessities. Although I will focus on Soames, my argument may have more general implications towards the prospects of providing a meaning-based account of metaphysical modality. (shrink)

This paper defends the idea that there must be some joints in reality, some correct way to classify or categorize it. This may seem obvious, but we will see that there are at least three conventionalist arguments against this idea, as well as philosophers who have found them convincing. The thrust of these arguments is that the manner in which we structure, divide or carve up the world is not grounded in any natural, genuine boundaries in the world. Ultimately they (...) are supposed to pose a serious threat to realism. The first argument that will be examined concerns the claim that there are no natural boundaries in reality, the second one focuses on the basis of our classificatory schemes, which the conventionalist claims to be merely psychological, and the third considers the significance of our particular features in carving up the world, such as physical size and perceptual capabilities. The aim of this paper is to demonstrate that none of these objections succeed in undermining the existence of genuine joints in reality. (shrink)

In this book, Scott Soames defends the revolution in philosophy led by Saul Kripke, Hilary Putnam, and David Kaplan against attack from those wishing to revive ..

Saul Kripke’s discussion of the necessary aposteriori in Naming and Necessity and “Identity and Necessity” -- in which he lays the foundation for distinguishing epistemic from metaphysical possibility, and explaining the relationship between the two – is, in my opinion, one of the outstanding achievements of twentieth century philosophy.1 My aim in this essay is to extract the enduring lessons of his discussion, and disentangle them from certain difficulties which, alas, can also be found there. I will argue that there (...) are, in fact, two Kripkean routes to the necessary aposteriori – one correct and philosophically far-reaching, the other incorrect and philosophically misleading. (shrink)

One common objection to Conventionalism about modality is that since it is contingent what our conventions are, the modal facts themselves will thereby be contingent. A standard reply is that Conventionalists can accept this, if they reject the S4 axiom, that what is possibly possible is possible. I first argue that this reply is inadequate, but then continue to argue that it is not needed, because the Conventionalist need not concede that the contingency of our conventions has any bearing on (...) the modal status of necessary truths. It is explained why this does not compromise the Conventionalist claim that necessity – and particularly, essence – is due to conventions. (shrink)

Any property has two sorts of causal features: “forward-looking” ones, having to do with what its instantiation can contribute to causing, and ldquo;backward-looking” ones, having to do with how its instantiation can be caused. Such features of a property are essential to it, and properties sharing all of their causal features are identical. Causal necessity is thus a special case of metaphysical necessity. Appeals to imaginability have no more force against this view than they do against the Kripkean view that (...) statements like “Gold is an element” are metaphysically necessary. (shrink)

Any property has two sorts of causal features: “forward‐looking” ones, having to do with what its instantiation can contribute to causing, and ldquo;backward‐looking” ones, having to do with how its instantiation can be caused. Such features of a property are essential to it, and properties sharing all of their causal features are identical. Causal necessity is thus a special case of metaphysical necessity. Appeals to imaginability have no more force against this view than they do against the Kripkean view that (...) statements like “Gold is an element” are metaphysically necessary. (shrink)

Robin Hendry has recently argued that although the term ‘element’ has traditionally been used in two different senses, there has nonetheless been a continuity of reference. The present article examines this author’s historical and philosophical claims and suggests that he has misdiagnosed the situation in several respects. In particular it is claimed that Hendry’s arguments for the nature of one particular element, oxygen, do not generalize to all elements as he implies. The second main objection is to Hendry’s view that (...) the qua problem can be illuminated by appeal to the intention of scientists.Keywords: Element; Simple substance; Basic substance; Antoine Lavoisier; Dmitri Mendeleev; Reference; Qua problem. (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)

This article is a translation into english of a lecture given by paneth in 1931. The content of the work is described by the section titles: (1) the need for epistemological clarification of the fundamental concepts of chemistry, (2) the concept of substance in chemistry, (3) the epistemological standpoint of the ancient atomists, (4) the epistemological position of the concept of element introduced by lavoisier, (5) the double meaning of the chemical concept of element: 'basic substance' and 'simple substance', And (...) (6) the double meaning of other chemical concepts. Sections (4)-(6) are published in the following number of this journal. (staff). (shrink)

This article is a translation into english of a lecture given by paneth in 1931. The content of the work is described by the section titles: (1) the need for epistemological clarification of the fundamental concepts of chemistry, (2) the concept of substance in chemistry, (3) the epistemological standpoint of the ancient atomists, (4) the epistemological position of the concept of element introduced by lavoisier, (5) the double meaning of the chemical concept of element: 'basic substance' and 'simple substance', And (...) (6) the double meaning of other chemical concepts. Sections (4)-(6) are published in the following number of this journal. (staff). (shrink)

This article is a translation into english of a lecture given by paneth in 1931. The content of the work is described by the section titles: (1) the need for epistemological clarification of the fundamental concepts of chemistry, (2) the concept of substance in chemistry, (3) the epistemological standpoint of the ancient atomists, (4) the epistemological position of the concept of element introduced by lavoisier, (5) the double meaning of the chemical concept of element: 'basic substance' and 'simple substance', And (...) (6) the double meaning of other chemical concepts. Sections (4)-(6) are published in the following number of this journal. (staff). (shrink)

Late nineteenth‐century opponents of atomism questioned whether the evidence required any notion of an atom. In this spirit, Duhem developed an account of the import of chemical formulas that is clearly neutral on the atomic question rather than antiatomistic. The argument is supplemented with specific inadequacies of atomic theories of chemical combination and considerably strengthened by the theory of chemical combination provided by thermodynamics. Despite possible counterevidence available at the time, which should have tempered some of Duhem's concluding remarks, there (...) was no atomic theory of chemical combination, which is wholly a product of the twentieth century. †To contact the author, please write to: Department of Philosophy, University of Stockholm, SE‐106 91 Stockholm, Sweden; e‐mail: [email protected]. (shrink)

‘Water is H 2 O’ is naturally construed as an equivalence. What are the things to which the two predicates ‘is water’ and ‘is H 2 O’ apply? The equivalence presupposes that substance properties are distinguished from phase properties. A substance like water (H 2 O) exhibits various phases (solid, liquid, gas) under appropriate conditions, and a given (say liquid) phase may comprise several substances. What general features distinguish substance from phase properties? I tackle these questions on the basis of (...) an interpretation of a theorem of thermodynamics known as Gibbs' phase rule which systematically relates these two kinds of feature of matter. The interpretation develops the idea that the things substance and phase predicates apply to are quantities of matter which sustain mereological relations and operations and exploits these mereological features in distinguishing the two kinds of property. Gibbs' phase rule is a macroscopic principle applicable for macroscopic intervals of time. Bringing intervals of time into the picture calls for a more detailed consideration of the relation between macroscopic equilibria and the corresponding dynamic equilibria at the microlevel and throws into question the simple idea that quantities can always be regarded as collections of molecules. The account provides some insight into how the continuous, macroscopic conception of matter (‘gunk’) is reconciled with the discrete microscopic conception and illuminates the interpretation of substances present in mixtures. (shrink)

Two inter-linked theses are defended in this paper. One is the Duhemian theme that a rigid distinction between physical and chemical properties cannot be upheld. Duhem maintained this view not because the latter are reducible to the former, but because if physics is to remain consistent with chemistry it must prove possible to expand it to accommodate new features, and a rigid distinction would be a barrier to this process. The second theme is that naturally occurring isotopic variants of water (...) are in fact distinct substances, and naturally occurring samples of water are mixtures of these substances. For most practical purposes it is convenient to treat protium oxide, deuterium oxide, and so on, as the same chemical substance, but to insist on this as a matter of principle would stand in conflict with the first thesis. (shrink)

This paper takes up issues related to the notion of chemical substances arising from their mereological and modal features. Related notions are elements and compounds, into which substances are sub-divided, and the general notion of mixture, which as a special case might involve several substances, but covers other cases too. These are essentially macroscopic concepts. Some of the chemical arguments for this claim have been presented elsewhere. The present paper is a metaphysical treatment of matter as categorised by the major (...) chemical concepts bearing on distinctions between homogeneous and heterogeneous matter, and between a single and several substances. (shrink)

According to microessentialism, it is necessary to resort to microstructure in order to adequately characterise chemical substances such as water. But the thesis has never been properly supported by argument. Kripke and Putnam, who originally proposed the thesis, suggest that a so-called stereotypical characterisation is not possible, whereas one in terms of microstructure is. However, the sketchy outlines given of stereotypical descriptions hardly support the impossibility claim. On the other hand, what naturally stands in contrast to microscopic description is description (...) in macroscopic terms, and macroscopic characterisations of water are certainly possible. This suffices to counter the claim that microdescriptions are necessary. Whether it counters the impossibility claim depends on whether all macroscopic descriptions are stereotypical (stereotypical descriptions presumably being macroscopic). In so far as systematic import of “stereotypical” can be determined, it would seem not. But some macroscopic characterisations have definite affinity with everyday knowledge, which presumably stands in conflict with the spirit of the impossibility claim. Since what is characterised are properties expressed by predicates like “is water”, the necessity of identity has no bearing here, and matters of interpretation pose problems for claims to the effect that science fixes the extension of “water” as ordinarily understood. (shrink)

‘Water is H2O’ is one of the most frequently cited sentences in analytic philosophy, thanks to the seminal work of Saul Kripke and Hilary Putnam in the 1970s on the semantics of natural kind terms. Both of these philosophers owe an intellectual debt to the empiricist metaphysics of John Locke's Essay Concerning Human Understanding, while disagreeing profoundly with Locke about the reality of natural kinds. Locke employs an intriguing example involving water to support his view that kinds (or ‘species’), such (...) as water and gold, are the workmanship of the human mind. This is the point of his story about a winter visitor to England from Jamaica, who is astonished to find that the water in his basin has turned solid overnight, and proceeds to call it ‘hardened water’. Locke criticizes this judgement, maintaining that it is more consonant with common sense to regard water and ice as different kinds of substance. Putnam, by implication, disagrees. Deploying his imaginary example of Twin Earth—a distant planet where a watery-looking substance, XYZ, rather than H2O, fills the oceans and rivers—he maintains that common sense supports the judgement that XYZ and H2O, despite their superficial similarity, are not the same kind of substance, precisely because their molecular compositions are different. Here it will be argued that both views are mistaken, but that, in this dispute, Locke has more right on his side than his modern opponents do. (shrink)

In this paper I defend, against Eric Scerri’s objections, the following theses: that Lavoisier and Mendeleev shared a ‘core conception’ of chemical element, and that this core conception underwrites referential continuity in the names of particular elements.Keywords: Antoine Lavoisier; Dmitri Mendeleev; Chemical elements; Substance; Natural kinds; Reference.

Lavoisier defined an element as a chemicalsubstance that cannot be decomposed usingcurrent analytical methods. Mendeleev saw anelement as a substance composed of atoms of thesame atomic weight. These `definitions' doquite different things: Lavoisier'sdistinguishes the elements from the compounds,so that the elements may form the basis of acompositional nomenclature; Mendeleev's offersa criterion of sameness and difference forelemental substances, while Lavoisier's doesnot. In this paper I explore the historical andtheoretical background to each proposal.Lavoisier's and Mendeleev's explicitconceptions of elementhood differed from eachother, and (...) from the official IUPAC definitionof `element' of the 1920s. However, Lavoisierand Mendeleev both subscribed to – andemployed – a deeper notion of a chemicalelement as the component of compound substancesthat (i) can survive chemical change, and (ii)explains the chemical behaviour of itscompounds. (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)

In this essay I critically examine the role of entropy of mixing in articulating a macroscopic criterion for the sameness and difference of chemical substances. Consider three cases of mixing in which entropy change occurs: isotopic variants, spin isomers, and populations of atoms in different orthogonal quantum states. Using these cases I argue that entropy of mixing tracks differences between physical states, differences that may or may not correspond to a difference of substance. It does not provide a criterion for (...) the sameness and difference of substance that is appropriate to chemistry. (shrink)

This paper argues that typical biological species are natural kinds, on a familiar realist understanding of natural kinds—classes of individuals across which certain properties cluster together, in virtue of the causal workings of the world. But the clustering is far from exceptionless. Virtually no properties, or property-combinations, characterize every last member of a typical species—unless they can also appear outside the species. This motivates some to hold that what ties together the members of a species is the ability to interbreed, (...) others that it is common descent. Yet others hold that species are scattered individuals,of which organisms are parts rather than members. But not one of these views absolves us of the need to posit a typical phenotypic profile. Vagueness is here to stay. Some seek to explain the vagueness by saying species are united by “homeostatic property clusters”; but this view collapses into the more familiar realist picture. (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.

Natural-kind essentialism faces an important but neglected difficulty: the problem of complex essences (PCE). This is the question of how to account for the unity of an instantiated kind-essence when that essence consists of multiple distinct properties, some of which lack an inherent necessary connection between them. My central goal here is to propose an essentialism-friendly solution to this problem. Along the way I also employ some points from that solution to argue for the necessary truth of essentialism (necessary, that (...) is, in all possible worlds in which there are material objects), and to support the essentialist ontology of laws over and against a major rival. (shrink)

Intrinsic biological essentialism (INBE) is the view that biological taxa have fixed identity conditions, conditions which consist at least in part of intrinsic properties. After a long period of near universal rejection within both philosophy of biology and theoretical biology, INBE is making a comeback. Here I attempt to support this revival by clarifying the nature of INBE, developing a new argument on its behalf, and addressing an important anti-essentialist critique.

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)

The “scientific essentialist” doctrine asserts that the following are examples of a posteriori necessary identities: water is H2O; gold is the element with atomic number 79; and heat is the motion of molecules. Evidence in support of this assertion, however, is difficult to find. Both Hilary Putnam and Saul Kripke have argued convincingly for the existence of a posteriori necessities. Furthermore, Kripke has argued for the existence of a posteriori necessary identities in regard to a particular class of statements involving (...) proper names. Neither Kripke nor Putnam, however, has argued convincingly that sentences containing syntactically complex terms or descriptive phrases can express a posteriori necessary identities. I will argue by way of a hypothetical example that ‘water is H2O’ does not express a necessary identity. My argument is unique in that it attacks the relevant sufficiency claim needed to underwrite this putative necessary identity.1 That is, even if we grant that water is necessarily composed of H2O, we should not accept that H2O necessarily forms water. (shrink)

This collection of essays, based on Saul Kripke's published and unpublished works, represents the most comprehensive analysis of his philosophy and writings available.

Are there natural kinds of things around which our theories cut? The essays in this volume offer reflections by a distinguished group of philosophers on a series of intertwined issues in the metaphysics and epistemology of classification.