The question ‘what is life?’ has long been a source of philosophical debate and in recent years has taken on increasing scientific importance. The most popular approach among both philosophers and scientists for answering this question is to provide a “definition” of life. In this article I explore a variety of different definitional approaches, both traditional and non-traditional, that have been used to “define” life. I argue that all of them are deeply flawed. It is my contention that a scientifically (...) compelling understanding of the nature of life presupposes an empirically adequate scientific theory (vs. definition) of life; as I argue, scientific theories are not the sort of thing that can be encapsulated in definitions. Unfortunately, as I also discuss, scientists are currently in no position to formulate even a tentative version of such a theory. Recent discoveries in biology and biochemistry have revealed that familiar Earth life represents a single example that may not be representative of life. If this is the case, life on Earth today provides an empirically inadequate foundation for theorizing about life considered generally. I sketch a strategy for procuring the needed additional examples of life without the guidance of a definition or theory of life, and close with an application to NASA’s fledgling search for extraterrestrial life. (shrink)

Many still seem confident that the kind of semantic theory Putnam once proposed for natural kind terms is right. This paper seeks to show that this confidence is misplaced because the general idea underlying the theory is incoherent. Consequently, the theory must be rejected prior to any consideration of its epistemological, ontological or metaphysical acceptability. Part I sets the stage by showing that falsehoods, indeed absurdities, follow from the theory when one deliberately suspends certain devices Putnam built into it , (...) presumably in order to block such entailments. Part II then raises the decisive issue of at what cost these devices do the job they need to do. It argues that - apart from possessing no other motivation than their capacity to block the consequences derived in Part I - they only fulfil this blocking function if they render the theory unable to deal with fiction and related 'make-believe' activities. Part III indicates the affinity Putnam's account has with the classically 'denotative' view of meaning, and thus how its weaknesses may be seen as a variant of the classical weakness of 'denotative' approaches. It concludes that the theory is a conceptual muddle. (shrink)

I reply to commentaries on my book Philosophy Without Intuitions from Paul Boghossian, Berit Brogaard, and Mark Richard.

Argues that natural kind terms are token-reflexive, with reference ultimately fixed to the underlying explanatory properties of the surface qualities of local matter.

The canonical arguments against the description theory of names are usually taken to have established that the reference of a name as used on a given occasion is not semantically determined by the qualitative descriptions that the speaker may have in mind. The deepest moral of these arguments, on the received view, would be that the speaker’s narrow mental states play no semantic role in fixing reference. My central aim in this paper is to challenge this common understanding by highlighting (...) that the same argumentative schemas can be adapted to undermine a related non-description theory, according to which the reference of a name as used on a given occasion would semantically depend on broad mental states of the speaker. Once this is realised, it becomes evident that the falsity of the description theory is not the deepest lesson of the canonical arguments, but only a consequence of the deepest lesson. The most fundamental moral is that the speaker’s mental states, whether narrow or broad, do not always determine linguistic reference. (shrink)

In this paper Modern Essentialism is used to solve a problem of individuation of spacetime points in General Relativity that has been raised by a New Leibnizian Argument against spacetime substantivalism, elaborated by Earman and Norton. An earlier essentialistic solution, proposed by Maudlin, is criticized as being against both the spirit of metrical essentialism and the fundamental principles of General Relativity. I argue for a modified essentialistic account of spacetime points that avoids those obstacles.

This paper investigates interactive kinds, a class of kinds suggested by Ian Hacking for which classification generates a feedback loop between the classifiers and what is classified, and argues that human interactive kinds should be distinguished from non-human ones. First, I challenge the claim that there is nothing ontologically special about interactive kinds in virtue of their members being classified as such. To do so, I reject Cooper’s counterexample to Hacking’s thesis that kind descriptions are necessary for intentional action, arguing (...) that classification is required for intentional action. Having considered ways to characterise the metaphysics of interactive kinds and the semantics of kind terms, I argue that the fact that classification facilitates intentional action makes human interactive kinds ontologically distinctive because of the anomalous nature of the change which the kind-classification brings about. I then briefly examine further distinguishing features of human interactive kinds. (shrink)

In this paper, I will outline some of the important points made by Kripke and Putnam on the meaning of natural kind terms. Their notion of the baptism of natural kinds- the process by which kind terms are initially introduced into the language — is of special concern here. I argue that their accounts leave some ambiguities that suggest a baptism of objects and kinds that is free of additional theoretical commitments. Both authors suggest that we name the stuff and (...) then let the scientists tell us what properties it really has, and hence what the real meaning is. I contend that such a barren baptism, taken at face value, cannot succeed in the semantic roles it has been assigned and that softening the stance on baptism suggests a more subtle and complex relation between reference and theoretical commitment than has emerged thus far. (shrink)

In Objectivity, Daston and Galison argue that scientific objectivity has a history. Objectivity emerged as a distinct nineteenth-century “epistemic virtue,” flanked in time by other epistemic virtues. The authors trace the origins of scientific objectivity by identifying changes in images from scientific atlases from different periods, but they emphasize that the same history could be narrated using different sorts of scientific objects. One could, for example, focus on the changing uses of “type specimens” in biological taxonomy. Daston :153–182, 2004) indeed (...) provides a detailed account of the history of the type specimen which purports to show this. I argue that this attempt hinges on a conceptual confusion and therefore fails. I show that the actual history of the type specimen does not reinforce the account of epistemic virtues from Objectivity, but rather threatens to subvert it. (shrink)

This paper discusses whether it can be known a priori that a particular term, such as water, is a natural kind term, and how this problem relates to Putnams claim that natural kind terms require an externalist semantics. Two conceptions of natural kind terms are contrasted: The first holds that whether water is a natural kind term depends on its a priori knowable semantic features. The second.

Sarah Sawyer has challenged my claim that social externalism depends on the assumption that individuals have an incomplete grasp of their own concepts. Sawyer denies that Burge's later sofa thought-experiment relies on this assumption: the unifying principle behind the thought-experiments supporting social externalism, she argues, is just that referents play a role in the individuation of concepts. I argue that Sawyer fails to show that social externalism need not rely on the assumption of incomplete understanding. To establish the content externalist (...) conclusions, further considerations are required, and these do commit the externalist to the assumption of incomplete understanding. (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.

In this paper I present a historiography of the recent emergence of philosophy of chemistry. Special attention is given to the interest in this domain in Eastern Europe before the collapse of the USSR. It is shown that the initial neglect of the philosophy of chemistry is due to the unanimous view in philosophy and philosophy of science that only physics is a proper science (to put in Kant's words). More recently, due to the common though incorrect assumption that chemistry (...) can in principle be reduced to physics, the neglect continued, even when interest in sciences such as biology and psychology entered more strongly in philosophy of science. It is concluded that chemistry is an autonomous science and is perhaps a more typical science than physics. (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)

Kripke (1982, Wittgenstein on rules and private language. Cambridge, MA: MIT Press) presents a rule-following paradox in terms of what we meant by our past use of “plus”, but the same paradox can be applied to any other term in natural language. Many responses to the paradox concentrate on fixing determinate meaning for “plus”, or for a small class of other natural language terms. This raises a problem: how can these particular responses be generalised to the whole of natural language? (...) In this paper, I propose a solution. I argue that if natural language is computable in a sense defined below, and the Church–Turing thesis is accepted, then this auxiliary problem can be solved. (shrink)

Good chefs know the importance of maintaining sharp knives in the kitchen. What’s their secret? A well-worn Taoist allegory offers some advice. The king asks about his butcher’s impressive knifework. “Ordinary butchers,” he replied “hack their way through the animal. Thus their knife always needs sharpening. My father taught me the Taoist way. I merely lay the knife by the natural openings and let it find its own way through. Thus it never needs sharpening” (Kahn 1995, vii; see also Watson (...) 2003, 46). Plato famously employed this image as an analogy for the reality of his Forms (Phaedrus, 265e). Just like an animal, the world comes pre-divided for us. Ideally, our best theories will be those which “carve nature at its joints”. While Plato employed the “carving” metaphor to convey his views about the reality of his celebrated Forms, its most common contemporary use involves the success of science -- particularly, its success in identifying distinct kinds of things. Scientists often report discovering new kinds of things -- a new species of mammal or novel kind of fundamental particle, for example -- or uncovering more information about already familiar kinds. Moreover, we often notice considerable overlap in different approaches to classification. As Ernst Mayr put it: No naturalist would question the reality of the species he may find in his garden, whether it is a catbird, chickadee, robin, or starling. And the same is true for trees or flowering plants. Species at a given locality are almost invariably separated from each other by a distinct gap. Nothing convinced me so fully of the reality of species as the observation . . . that the Stone Age natives in the mountains of New Guinea recognize as species exactly the same entities of nature as a western scientist. (Mayr 1987, 146) Such agreement is certainly suggestive. It suggests that taxonomies are discoveries rather than mere inventions. Couple this with their utility in scientific inference and explanation and we have compelling reason for accepting the objective, independent reality of many different natural kinds of things.. (shrink)

Consciousness in experimental subjects is typically inferred from reports and other forms of voluntary behaviour. A wealth of everyday experience confirms that healthy subjects do not ordinarily behave in these ways unless they are conscious. Investigation of consciousness in vegetative state patients has been based on the search for neural evidence that such broad functional capacities are preserved in some vegetative state patients. We call this the standard approach. To date, the results of the standard approach have suggested that some (...) vegetative state patients might indeed be conscious, although they fall short of being demonstrative. The fact that some vegetative state patients show evidence of consciousness according to the standard approach is remarkable, for the standard approach to consciousness is rather conservative, and leaves open the pressing question of how to ascertain whether patients who fail such tests are conscious or not. We argue for a cluster-based ‘natural kind’ methodology that is adequate to that task, both as a replacement for the approach that currently informs research into the presence or absence of consciousness in vegetative state patients and as a methodology for the science of consciousness more generally. 1. Introduction2. The Vegetative State3. The Standard Approach4. The Natural Kind Methodology5. Is Consciousness a Special Case? 5.1 Is consciousness a natural kind?5.2 A special obstacle?6. Conclusion. (shrink)

Most contemporary analytic philosophers of language and mind accept the view that there is a wide class of terms, “natural kind terms”, which includes names of substances (the most common example is “water”), of species of animals, and of many other kinds of things in nature, whose meaning and reference is determined in the way explained by the theory developed in the 1970s by Saul Kripke and Hilary Putnam. The theory is often referred to as “the Kripke-Putnam theory” and is (...) supposed to have such achievements as the overthrow of the earlier dominant Fregean theory of word-meanings (dubbed “descriptivism” by Kripke) as determined by the concepts in our minds, providing support for the “externalist” approach to linguistic meanings (in line with Putnam’s claim that “"Meanings" just ain’t in the head”), and the discovery that there is a wide class of truths (such as that water is H20) that are both a posteriori and necessary. Although the priority in the development of this theory belongs to Kripke, it could hardly gain such a wide acceptance without contributions by Putnam, which turned out to be very influential. However, the habitual idea of “the Kripke-Putnam theory”, as one theory, tends to play down the differences between Putnam’s and Kripke’s approaches and to hush up the fact that in his late works, of 1983 and 1990, Putnam revised and abandoned pretty much of his “Kripkean” views of 1970-ies; in particular, repudiated the pride of Kripke’s theory, the idea of necessary a posteriori truths. This article makes critical analysis and evaluation of Putnam’s ideas and arguments usually credited as important contributions to “the Kripke-Putnam theory”, and highlights the main points of the revision in late Putnam’s works. The case is made that Putnam's famous argument for externalism about meanings, the Twin-Earth thought experiment, is question-begging, fails to do justice to likely changes in the meanings of words with the development of knowledge, and conflicts with the linguistic practice in the relevantly similar case of “jade”. Putnam's argument for externalism from the division of linguistic labour is not cogent too, because “semantic deference” is itself a matter of what is there in “heads” - of some (non-expert) heads deferring to other (recognised as expert) heads. Eventually, on close inspection and in the light of Putnam's later reexplanation and revision, his account of meaning and reference turns out to be a sophisticated variety of conceptualism/internalism. (shrink)

A critique of LaPorte's views on chemical kinds, like jade and ruby, is presented. More positively, a new slant is provided on the question of whether elements are natural kinds. This is carried out by appeal to the dual nature of elements, a topic that has been debated in the philosophy of chemistry but not in the natural kinds literature. It is claimed that the abstract notion of elements, as opposed to their being simple substances, is relevant to the Kripke–Putnam (...) approach to natural kinds and to some criticisms that have been raised against it, although I do not support the K–P account. The proposed view avoids the traditional microstructuralist approach to natural kinds. The article also addresses the question of whether natural kinds concern metaphysical or epistemological considerations. Recent attempts by chemists to modify the periodic table are brought to bear on the question of classification and consequently on whether the identification of elements is interest dependent. (shrink)

The term philosophy of chemistry is here construed broadly to include some publications from the history of chemistry and chemical education. Of course this initial selection of material has inevitably been biased by the interests of the author. This bibliography supersedes that of van Brakel and Vermeeren (1981), although no attempt has been made to include every single one of their entries, especially in languages other than English. Also, readers interested particularly in articles in German may wish to consult the (...) bibliography by Dittus and Mayer which also contains some material not included here (Dittus and Mayer, 1992). The aim is to maintain an up-to-date version of this bibliography and to publish a revised version in due course. Suggestions for further inclusions should be sent to the author. (shrink)

Scott Soames (2002) has recently developed and defended strategies for (i) accounting for the meaning of Millian terms, and (ii) extending Kripke's insights from proper names to natural kind terms. In this paper I argue that if we accept these strategies, and their implausible assumptions and consequences, then we can present a novel defence of descriptivism for at least some natural kind terms – those for substances – on that basis. The conclusion, then, will be that there is just no (...) motivation for being a Soamesian Kripkean for an important class of natural kind terms. (shrink)

forthcoming in Philosophy and Phenomenological Research.

A number of philosophers defend naturalistic moral realism by appeal to an externalist semantics for moral predicates. The application of semantic externalism to moral predicates has been attacked by Terence Horgan and Mark Timmons in a series of papers that make use of their “ Moral Twin Earth ” thought experiment. In response, several defenders of naturalistic moral realism have claimed that the Moral Twin Earth thought experiment is misleading and yields distorted and inaccurate semantic intuitions. If they are right, (...) the intuitions generated by Moral Twin Earth cannot be appealed to in arguments against externalist moral semantics. The most developed case against the Moral Twin Earth argument that follows this strategy is found in a paper by Stephen Laurence, Eric Margolis and Angus Dawson. Here I argue that their attack on the Moral Twin Earth thought experiment fails. Laurence, Margolis and Dawson have not shown that we have reason to distrust the semantic intuitions it generates. (shrink)

According to Essentialism, an object’s properties divide into those that are essential and those that are accidental. While being human is commonly thought to be essential to Socrates, being a philosopher plausibly is not. We can motivate the distinction by appealing—as we just did—to examples. However, it is not obvious how best to characterize the notion of essential property, nor is it easy to give conclusive arguments for the essentiality of a given property. In this paper, I elaborate on these (...) issues and explore the way in which essential properties behave in relation to other related properties, like sufficient-for-existence properties and individual essences. (shrink)

A long-standing debate has dominated systematic biology and the ontological commitments made by its theories. The debate has contrasted individuals and the part – whole relationship with classes and the membership relation. This essay proposes to conceptualize the hierarchy of higher taxa is terms of a hierarchy of homeostatic property cluster natural kinds (biological species remain largely excluded from the present discussion). The reference of natural kind terms that apply to supraspecific taxa is initially fixed descriptively; the extension of those (...) natural kind terms is subsequently established by empirical investigation. In that sense, classification precedes generalization, and description provides guidance to empirical investigation. The reconstruction of a hierarchy of (homeostatic property cluster) natural kinds is discussed in the light of cladistic methods of phylogeny reconstruction. (shrink)

This article explores the theory of natural kind essentialism, as developed by Putnam and Kripke. It defends the theory against certain criticisms, but also suggests that it should not be treated as universally true. Rather, it comes down to how different people use language, offering reasons why some people's idiolects might behave in an essentialist way while others behave in the contrary way, but explaining how we can all still communicate perfectly well despite this.

The new externalist picture of natural kind terms due to Kripke, Putnam, and others has become quite popular in philosophy. Many philosophers of science have remained sceptical. Häggqvist and Wikforss have recently criticised this view severely. They contend it depends essentially on a micro-essentialist view of natural kinds that is widely rejected among philosophers of science, and that a scientifically reasonable metaphysics entails the resurrection of some version of descriptivism. It is argued in this paper that the situation is not (...) quite as dark for the new theory of reference as many critics suggest. There are several distinct questions here which should not be conflated and ought to be dealt with one by one. Descriptivism remains arguably problematic. (shrink)

The most popular and influential strategies used against semantic externalism and the causal theory of reference are critically examined. It is argued that upon closer scrutiny, none of them emerges as truly convincing.

Natural Categories and Human Kinds is a recent and timely contribution to current debate on natural kinds. Because of the growing sophistication of this debate, it is necessary to make careful distinctions in order to appreciate the originality of Khalidi’s position. Khalidi’s view on natural kinds is naturalistic: if we want to know what Nature’s joints really are, we should look at the actual carving job carried out by our best scientific practices. Like LaPorte, Khalidi is a fallibilist: our best (...) scientific theories may be revised or abandoned and so can our current classifications of natural kinds. Unlike LaPorte, however, Khalidi is an anti-essentialist: he argues against the idea that membership in a natural kind is a matter of possessing an essential set of necessary and sufficient properties. Like Dupré, Khalidi is a pluralist and anti-reductionist: he does not believe that there is only one true classification system and that there are natural kinds only at the so-called "fundamental level" of microphysics. Khalidi develops his pluralistic and anti-reductionistic position on the basis of a deep appreciation for the special sciences but, unlike Dupré, he thinks that only the scientific inquiry, which is driven by epistemic purposes, discover natural kinds and that, therefore, there are important differences between scientific and folk classifications. Khalidi’s conception of natural kinds has both an epistemic and a metaphysical component. (shrink)

de Queiroz (1995), Griffiths (1999) and LaPorte (2004) offer a new version of essentialism called "historical essentialism". According to this version of essentialism, relations of common ancestry are essential features of biological taxa. The main type of argument for this essentialism proposed by Griffiths (1999) and LaPorte (2004) is that the dominant school of classification, cladism, defines biological taxa in terms of common ancestry. The goal of this paper is to show that this argument for historical essentialism is unsatisfactory: cladism (...) does not assume that relations of common ancestry are essential attributes of biological taxa. Therefore, historical essentialism is not justified by cladism. (shrink)

What is the new essentialist asking us to accept? Not that there are natural kinds, nor that there are intrinsic causal powers. These things could be accepted without a commitment to essentialism. They are asking us to accept something akin to the Kripke‐Putnam position: a metaphysical theory about kind‐membership in virtue of essential properties. But Salmon has shown that there is no valid argument for the Kripke‐Putnam position: no valid inference that gets us from reference to essence. Why then should (...) we accept essentialism? A remaining reason is Ellis's argument by display: we should buy essentialism because of the benefits it will bring. But are these benefits real? The problem is that the putative benefits of essentialism – that the laws of nature are necessary, that the problem of induction is solved, and so on – look actually to be the assumptions of Ellis's theory. If that is the case, there is no real benefit to be gained from adopting the theory. The argument for essentialism is therefore underdetermined and it remains possible to accept natural kinds into one's ontology without accepting their corresponding essences. (shrink)

Abstract Taking the integrated viewpoints of causal theory of reference, cognitive science and the notion of correspondence principles from physics, this paper addresses the problems of creativity, the nature of visual imagery and the manner in which science progresses.

I propose to support these replies with actual episodes in late nineteenth and twentieth century physics. The historical record reveals that meaning does change but not in the Kuhnian manner which is tied to descriptive theories of meaning. A necessary part of this discussion is commentary on realist versus antirealist conceptions of science.

The paper develops a unified account of both deterministic and indeterministic laws of nature which inherits the merits but not the defects of the best existing accounts. As in Armstrong's account, laws are embodied in facts about universals; but not in higher‐order relations between them, and the necessity of laws is not primitive but results from their containing chances of 0 or 1. As in the Ramsey‐Lewis account, law statements would be the general axioms and theorems of the simplest deductive (...) theory of everything; but because laws are not so defined, simplicity of statement is not a criterion of law‐hood. (shrink)

This paper addresses a famous objection against David Lewis’s Best System Analysis (BSA) of laws of nature. The objection—anticipated and discussed by Lewis (1994)—focuses on the standards of simplicity and strength being (in part) a matter of psychology. Lewis’s answer to the objection relies on his metaphysics of natural properties and its ability to single out the robustly best system, a system that is expected to come out far ahead of its rivals under any standard of simplicity and strength. The (...) main task of this paper is to argue that Lewis’s reply to the objection in terms of nature being kind to us does not succeed, if nature’s kindness is understood in terms of the naturalness of the properties composing the Humean mosaic. For epistemic access to natural properties is downstream to any previous identification of the best system. A possible Lewisian rejoinder in terms of a cross-world Humean mosaic of natural properties is considered and rebutted. The paper concludes by suggesting that Lewis could instead avail himself of a better answer to the objection, if the standards of simplicity and strength were reinterpreted along perspectivalist lines. (shrink)

The paper offers a new understanding of induction in the empirical sciences, one which assimilates it to induction in geometry rather than to statistical inference. To make the point a system of notions, essential to logically sound induction, is defined. Notable among them are arbitrary object and particular property. A second aim of the paper is to bring to light a largely neglected set of assumptions shared by both induction and deduction in the empirical sciences. This is made possible by (...) appealing to the logic of common nouns and applying it to the logic of natural-kind terms.This strategy yields a new insight into the concept of natural kinds. While the strategy reveals deep affinity between empirical induction and deduction it also reveals two problems peculiar to induction. This helps to explain the intuition that induction is the more problematic of the two. The paper does not set out ‘to solve the problem of induction’. 1The paper has benefited from the support and critical comments of several friends: Steven Davis, Kevin Dunbar, Anil Gupta, Michael Hallett, Ray Jackendoff and Storrs McCall. Two friends, however, deserve special thanks, Michael Makkai and Gonzalo Reyes. Many of the points made in the paper, otherwise unacknowledged, are due to their generosity and patience. In fact, the paper can be seen as an application of the logic of kinds on which Gonzalo Reyes has been working for several years. (shrink)

This article uses the case study of ethnobiological classification to develop a positive and a negative thesis about the state of natural kind debates. On the one hand, I argue that current accounts of natural kinds can be integrated in a multidimensional framework that advances understanding of classificatory practices in ethnobiology. On the other hand, I argue that such a multidimensional framework does not leave any substantial work for the notion “natural kind” and that attempts to formulate a general account (...) of naturalness have become an obstacle to understanding classificatory practices. (shrink)

In this paper I take issue with the doctrine that organisms belong of their very essence to the natural kinds (or biological taxa, if these are not kinds) to which they belong. This view holds that any human essentially belongs to the species Homo sapiens, any feline essentially belongs to the cat family, and so on. I survey the various competing views in biological systematics. These offer different explanations for what it is that makes a member of one species, family, (...) etc. a member of that taxon. Unfortunately, none of them offers an explanation that is compatible with the essentialism in question. (shrink)

The aim of this article is to illustrate how a belief in the existence of kinds may be justified for the particular case of natural kinds: particularly noteworthy in this respect is the weight borne by scientific natural kinds (e.g., physical, chemical, and biological kinds) in (i) inductive arguments; (ii) the laws of nature; and (iii) causal explanations. It is argued that biological taxa are properly viewed as kinds as well, despite the fact that they have been by some alleged (...) to be individuals. Since it turns out that the arguments associated with the standard Kripke/Putnam semantics for natural kind terms only establish the non-descriptiveness of natural kind terms and not their rigidity, the door is open to analyze these terms as denoting traditional predicate-extensions. Finally, special issues raised by physical and chemical kinds are considered briefly, in particular impurities, isotopes and the threat of incommensurability. (shrink)

In The Philosophy of Philosophy, Tim Williamson has offered a sophisticated account of thought experiments and of modal epistemology. More recently, he has also engaged in a variant of the so-called ‘expertise defence’ of traditional philosophical methodology. In this paper I argue that if Williamson’s account of thought experiments and of modal epistemology is right, this seriously undermines his version of the expertise defence.

There is a perennial philosophical dream of a certain natural order for the natural kinds. The name of this dream is ‘the hierarchy requirement’. According to this postulate, proper natural kinds form a taxonomy which is both unique and traditional. Here I demonstrate that complex scientific objects exist: objects which generate different systems of scientific classification, produce myriad legitimate alternatives amongst the nonetheless still natural kinds, and make the hierarchical dream impossible to realize, except at absurdly great cost. Philosophical hopes (...) for a certain order in nature cannot be fulfilled. Natural kinds crosscut one another, ubiquitously so, and this crosscutting spells the end of the hierarchical dream. (shrink)

Following the influential thought experiments by Hilary Putnam and others, philosophers of language have for the most part adopted semantic externalism concerning natural kind terms. In this article, we present results from three experiments on the reference of natural kind terms. Our results confirm some standard externalist assumptions, but are in conflict with others: Ordinary speakers take both appearance and underlying nature to be central in their categorization judgments. Moreover, our results indicate that speakers’ categorization judgments are gradual, and proportional (...) to the degree of similarity between new samples and familiar, “standard” samples. These findings pose problems for traditional theories, both externalist and internalist. (shrink)