The notion of rigidity looms large in philosophy of language, but is beset by difficulties. This paper proposes a simple theory of rigidity, according to which an expression has a world-relative semantic property rigidly when it has that property at, or with respect to, all worlds. Just as names, and certain descriptions like The square root of 4, rigidly designate their referents, so too are necessary truths rigidly true, and so too does cat rigidly have only animals in its extension. (...) After spelling out the theory, I argue that it enables us to avoid the headaches that attend the misbegotten desire to have a simple rigid/non-rigid distinction that applies to expressions, giving us a simple solution to the problem of generalizing the notion of rigidity beyond singular terms. (shrink)

The principal question addressed is whether there is a division among common nouns which is similar to a familiar division among noun phrases that designate particular-level individuals: the one which is captured in the relevant literature as the difference between de jure rigid and not de jure rigid singular terms. In relation with the previous philosophical literature relevant to noun rigidity it is argued that the extant positions on the matter are not defended on the basis of well-founded syntactic categories (...) and proper semantic arguments. Proper ways to argue for rigidity ascriptions to nouns are described. Then, such arguments are sought for the case of rigid/non-rigid division among count common nouns. It is shown that there are plausible, albeit inconclusive, reasons to hold that among common nouns (N-bar expressions) only simple common nouns are kind designators, and that if that is the case these simple common nouns will have to be reckoned as de jure rigid designators. (shrink)

In this paper certain aspects of rigidity are studied through Hintikka’s work in modal semantics. The paper surveys Hintikka’s extraordinary struggles with rigidity from the late 50’s to this millennium. I argue that Hintikka’s many ambivalent remarks concerning rigidity become more comprehensible if, first, three different variants of rigidity are distinguished and, second, Hintikka’s largely implicit doctrine of semantic neo-Kantianism is made explicit.

The classification-cum-explanation Kripke assigns to rigidity requires the notion to apply to singular and general terms alike. But Kripke's own notion of rigidity is tailor-made for singular terms, and an extensive debate has not secured a general notion of rigidity apt to provide the classification-cum-explanation Kripke aims for. I propose that we look for a Kripkean alternative to generalized rigidity. I argue that on Kripkean premises, natural kind terms and proper names belong to the meta-semantic category of paradigm terms. I (...) also argue that the property of being a paradigm term effects precisely the classification-cum-explanation Kripke attributes to rigidity. I conclude that Kripkeans should acknowledge that being a paradigm term, rather than designating rigidly, plays the role Kripke delineates, and that we can stop worrying about generalizing rigidity. Kripke's notion works fine for singular terms. And there is no need for rigidity to apply beyond these. (shrink)

The rigid designation of proper names and natural kind terms is the most well-known doctrine of Kripke’s Naming and Necessity (1981). On the basis of rigidity, Kripke has shown that proper names and natural kind terms do not refer via a description as argued by descriptivists. In response to Kripke several people have argued that all general terms could be interpreted rigidly, which would make the notion of rigidity trivial. This leads to the ‘rigidity problem’: the notion of rigidity cannot (...) be used to argue against descriptivism anymore. I will show that the rigidity problem appears on a larger scale: firstly, because it appears independently of the trivialisation problem, secondly, because it appears for descriptions acting like singular terms as well. I will argue, however, that proper names and natural kind terms differ in an important manner from rigid descriptions. While the first are de jure rigid, the latter are de facto rigid. I will show that the rigidity problem indeed appears for de facto rigidity, but not for de jure rigidity, with the result that Kripke’s argument against descriptivism can withstand. (shrink)

Rigid expressionism is the view that all natural kind terms and many other kind terms are rigid designators. Rigid expressionists embrace the ‘overgeneralization’ of rigidity, since they hold that not just natural kind terms but all unstructured kind terms are rigid designators. Unfortunately overgeneralization remains a defeating problem for rigid expressionism. It runs together natural kind terms and nominal kind terms in a way that enforces a false semantic uniformity. The Kripke/putnam view of natural kind terms minus the claim of (...) rigidity is correct, but a traditional descriptivist theory is appropriate for nominal kind terms. None of them should be thought of as either rigid or non-rigid, however. (shrink)

Husserl’s Logical Grammar is intended to explain how complex expressions can be constructed out of simple ones so that their meaning turns out to be determined by the meanings of their constituent parts and the way they are put together. Meanings are thus understood as structured contents and classified into formal categories to the effect that the logical properties of expressions reflect their grammatical properties. As long as linguistic meaning reduces to the intentional content of pre-linguistic representations, however, it is (...) not trivial to account for how semantics relates to syntax in this context. In this paper, I analyze Husserl’s Logical Grammar as a system of recursive rules operating on representations and suggest that the syntactic form of representations contributes to their semantics because it carries information about semantic role. I further discuss Husserl’s syntactic account of the unity of propositions and argue that, on this account, logical form supervenes on syntactic form. In the last section I draw some implications for the phenomenology of thought and conjecture that the structural features it displays are likely to convey the syntactic structures of an underlying language-like representational system. (shrink)

In this paper, I dwell on a particular distinction introduced by Ilhan Inan—the distinction between ostensible and inostensible use of our language. The distinction applies to singular terms, such as proper names and definite descriptions, or to general terms like concepts and to the ways in which we refer to objects in the world by using such terms. Inan introduces the distinction primarily as an epistemic one but in his earlier writings (1997: 49) he leaves some room for it to (...) have some semantic significance i.e., the view that in certain intensional de re contexts whether a term occurring in a sentence is ostensible or inostensible may have a bearing on the semantic content of the sentence. However, in his later writings e.g., The Philosophy of Curiosity, he appears to abandon his earlier thoughts regarding the semantic significance of his distinction. He says: “the ostensible/inostensible distinction is basically an epistemic one.... It is an epistemic distinction that has no semantic significance” (2012: 65). I argue that there are indeed such intensional contexts in which the distinction has some semantic significance, i.e., whether a term is ostensible or inostensible has in fact a bearing on what proposition is expressed by the sentence in which the term occurs. (shrink)

In this essay, I present a problem that originates in Kripke's contention, in Naming and Necessity, that natural kind terms are rigid, namely, the problem of how to understand the notion of rigidity when it is applied to general terms. I also give an account, in a principled way, of the main theoretical options that seem to be available to solve that problem, and sketch the main features of Michael Devitt's proposal against that background. En este trabajo, hago una presentación (...) de un problema que Kripke deja planteado al sostener, en El nombrar y la necesidad, que los términos de género natural son rígidos, a saber, el de cómo debería ser entendida la noción de rigidez cuando ésta es aplicada a los términos generales. Asimismo, trazo un panorama de las distintas opciones teóricas disponibles, y presento las tesis centrales de la propuesta de Michael Devitt a la luz de este marco. (shrink)

Natural kind terms have exercised philosophical fancy ever since Kripke, in Naming and Necessity, claimed them to be rigid designators. He there drew attention to the peculiar, name-like behavior of a family of prima facie loosely related general terms of ordinary English: terms such as ‘water’, ‘tiger’, ‘heat’, and ‘red’. Just as for ordinary proper names, Kripke argued that such terms cannot be synonymous with any of the definite descriptions ordinary speakers associate with them. Rather, the name-like behavior of these (...) so-called natural kind terms is to be explained, just as in in the case of proper names, by the doctrine of rigid designation. And as a consequence of thus extending the notion of rigid designation to general terms, he famously endorsed the claim that so-called ‘theoretical identifications’, i.e. statements like (1) Water is H2O, are necessary, if true. (shrink)

It is commonly assumed that natural kind terms constitute a distinct semantic category. This idea emerged during the 1970's following Kripke's and Putnam's well-known remarks on natural kind terms. The idea has stayed with us, although it is now recognized that the issues are considerably more complex than initially thought. Thus, it has become clear that much of Kripke's and Putnam's discussions were based on rather simplified views of natural kinds. It also turns out that the semantic issues are less (...) straightforward than assumed - in particular, it is far from clear what it might mean to say that a kind term is rigid. Strikingly, however, these worries have not done much to undermine the confident assumption that natural kind terms form a special semantic category. In the paper I try to shake that confidence. I argue that although natural kind terms are no doubt important (for instance, from an explanatory point of view), we are certainly not warranted in concluding that they form a separate, semantic category among the kind terms. (shrink)

What does it mean for a general term to be rigid? It is argued by some that if we take general terms to designate their extensions, then almost no empirical general term will turn out to be rigid; and if we take them to designate some abstract entity, such as a kind, then it turns out that almost all general terms will be rigid. Various authors who pursue this line of reasoning have attempted to capture Kripke’s intent by defining a (...) rigid general term as one that applies to the objects in its extension essentially. I argue that this account is significantly mistaken for various reasons: it conflates a metaphysical notion (essentialism) with a semantic one (rigidity); it fails to countenance the fact that any term can be introduced into a language by stipulating that it be a rigid designator; it limits the extension of rigid terms so much that terms such as ‘meter’, ‘rectangle’, ‘truth’, etc. do not turn out to be rigid, when they obviously are; and it wrongly concentrates on the predicative use of a general term in applying a certain test offered by Kripke to determine whether a term is rigid. (shrink)

Penelope Mackie and Scott Soames argue, contrary to my Reference and Essence (R&E), that Hilary Putnam was correct that the direct-reference theory of natural-kind terms, taken in conjunction with empirical or otherwise uncontroversial premises, yields non-trivial essentialism, such as the conclusion that water is essentially two-parts hydrogen, one-part oxygen. A controversial distinction is drawn between rigid and non-rigid general terms. A new criterion for general-term rigidity is proposed, and Putnam’s ostensive definition of ‘water’ is reformulated accordingly to generate the consequence (...) that ‘water’ rigidly designates. Mackie and Soames propose a reformulation of Putnam’s ostensive definition that putatively yields the desired result. This reformulation, however, does not correctly explain the meaning of ‘water’ as a substance designator. Furthermore, if taken instead as a redefinition of ‘water’, the essentialism thereby generated is trivial. (shrink)

The aim of this thesis is to discuss whether general terms are rigid and if they are, how their rigidity should be interpreted. To this end, I first present the problems related to the rigidity of general terms. The most important ones among them are the following: What do general terms refer to? Is there any difference between the terms called “natural kind terms” and other general terms? After that, I discuss the arguments of three competent interpretations which try to (...) overcome these problems. The first interpretation holds that general terms refer to (or apply to) each and every object in their extensions. According to this view, only general terms related to essential properties like “cat”, “gold” turn out to be rigid. After I try to expose the drawbacks of this view, I examine the arguments of the second interpretation which holds that general terms refer to abstract kinds. I also argue for this interpretation. According to this interpretation general terms which refer to the same kind in all possible worlds turn out to be rigid. The main objection to this view is that this interpretation makes so many general terms rigid and it trivializes the notion of rigidity. Arguing that this is an unfair objection, I also focus on the philosophical importance of the subject and show that the interpretation I argue for realizes this philosophical importance. The third interpretation, on the other hand, rejects the rigidity of general terms. I also discuss the drawbacks of this view. -/- Another subject I discuss in the thesis is the rigidity of artifactual kind terms. The kinds of human made objects for specific purposes are usually called “artifactual kinds”. I argue that artifactual kind terms could rigidly refer to artifactual kinds. I reply to the critiques of this view with regard to the semantics of artifactual kind terms and metaphysics of artifactual kinds. (shrink)

This volume draws connections between Wittgenstein's philosophy and the work of Saul Kripke, especially his Naming and Necessity. Saul Kripke is regarded as one of the foremost representatives of contemporary analytic philosophy. His most important contributions include the strict distinction between metaphysical and epistemological questions, the introduction of the notions of contingent a priori truth and necessary a posteriori truth and original accounts of names, descriptions, identity, necessity and realism. The chapters in this book elucidate the relevant connections between Kripke's (...) work and Wittgenstein, specifically concerning the standard meter, contingent apriori and rule-following. The contributions shed light on how Kripke's philosophical outlook was influenced by Wittgenstein, and how mainstream analytic philosophy and Wittgensteinian philosophy can fruitfully engage with one another. Kripke and Wittgenstein will be of interest to philosophers working on Wittgenstein, Kripke, and the history of analytic philosophy. (shrink)

The question whether the notion of rigidity can be extended in a fruitful way beyond singular terms has received a standard answer in the literature, according to which non-singular terms designate kinds, properties or other abstract singular objects and generalized rigidity is the same thing as singular term rigidity, but for terms designating such objects. I offer some new criticisms of this view and go on to defend an alternative view, on which non-singular terms designate extensions in general, and generalized (...) rigidity is identity of extension across possible worlds. I develop some fundamental positive considerations that make this view virtually inevitable as a view of generalized rigidity, emphasizing its exclusive ability to offer a purely logical justification of the necessity of several kinds of statements that go beyond true identity statements between rigid singular terms. (shrink)

This paper deals with the semantics and meta-semantics for ordinary names in fiction. It has recently been argued by some philosophers that when ordinary names are used in fictional contexts, they change their semantic contents and work as fictional names in general. In this paper, I argue that there is no compelling reason to believe that such reference changes occur and defend the view that whether those names refer to real or fictional objects depends on which semantic intentions speakers have.

In this paper I am concerned with the problem of applying the notion of rigidity to general terms. In Naming and Necessity, Kripke has clearly suggested that we should include some general terms among the rigid ones, namely, those common nouns semantically correlated with natural substances, species and phenomena, in general, natural kinds -'water', 'tiger', 'heat'- and some adjectives -'red', 'hot', 'loud'. However, the notion of rigidity has been defined for singular terms; after all, the notion that Kripke has provided (...) us with is the notion of a rigid designator. But general terms do not designate single individuals: rather, they apply to many of them. In sum, the original concept of rigidity cannot be straightforwardly applied to general terms: it has to be somehow redefined in order to make it cover them. As is known, two main positions have been put forward to accomplish that task: the identity of designation conception, according to which a rigid general term is one that designates the same property or kind in all possible worlds, and the essentialist conception, which conceives of a rigid general term as an essentialist one, namely, a term that expresses an essential property of an object. My purpose in the present paper is to defend a particular version of the identity of designation conception: on the proposed approach, a rigid general term will be one that expresses the same property in all possible worlds and names the property it expresses. In my opinion, the position can be established on the basis of an inference to the best explanation of our intuitive interpretation and evaluation, relative to counterfactual circumstances, of statements containing different kinds of general terms, which is strictly analogous to our intuitive interpretation and evaluation, relative to such circumstances, of statements containing different kinds of singular ones. I will argue that it is possible to offer a new solution to the trivialization problem that is thought to threaten all versions of the identity of designation conception of rigidity. Finally, I will also sketch a solution to the so-called 'over-generalization and under-generalization problems', both closely related to the above-mentioned one. (shrink)

It is generally assumed that rigidity plays a key role in explaining the necessary a posteriori status of identity statements, both between proper names and between natural kind terms. However, while the notion of rigid designation is well defined for singular terms, there is no generally accepted definition of what it is for a general term to be rigid. In this paper I argue that the most common view, according to which rigid general terms are the ones which designate the (...) same kind in all possible worlds, fails to deliver a posteriori necessities. I also present an alternative view, on which the work of explaining a posteriori necessities is not done by rigidity, but by a related metasemantic notion, which I call actuality - dependence. (shrink)

The causal theory of reference is often taken to provide a solution to the problems, such as incomparability and referential discontinuity, that the meaning-change thesis raised. I show that Kuhn successfully questioned the causal theory and Putnam's idea that reference is determined via the sameness relation of essences that holds between a sample and other members of a kind in all possible worlds. Putnam's single ‘essential' properties may be necessary but not sufficient to determine membership in a kind category. Kuhn (...) argued that extension is fixed by similarity-dissimilarity relations that are liable to change in taxonomic reorganizations of science. *Received October 2009; revised January 2010. †To contact the author, please write to: Institute of Philosophy, University of Leiden, Martin de Vrieshof 4, 2300 RS Leiden, The Netherlands; e-mail: [email protected]. (shrink)

In his paper "Rigid Application", Michael Devitt defends a particular version of the socalled 'essentialist conception' of rigidity for general terms, according to which rigid general terms are rigid appliers, namely, terms that if they apply to an object in any possible world then they apply to that object in every possible in which the object exists. Devitt thinks that the thereby defined notion of rigidity makes for an adequate extension to general terms of Kripke's notion, originally defined for singular (...) ones, inasmuch as it serves to accomplish its same primary task: namely, "to distinguish terms that are not covered by a description theory from ones that are". He then criticizes the alternative conception of rigidity for general terms as identity of designation -specifically, LaPorte´s version- on the basis of its entanglement with some controversial metaphysical theses regarding the existence of universals -including a commitment to a selective realism concerning them. In this paper, I try to defend the identity of designation conception from his criticisms: with this aim, I propose a version different from LaPorte's, and claim it to be the best one to accomplish the above-mentioned primary semantic task, namely, the one of showing that some general terms, just like most ordinary names, cannot be accounted for in descriptive terms. En su artículo "Rigid Application", Michael Devitt defiende una versión particular de la llamada 'concepción esencialista' de la rigidez para términos generales, según la cual los términos generales rígidos son aplicadores rígidos, esto es, términos que si se aplican a un objeto en algún mundo posible, se aplican a ese objeto en todos los mundos posibles en los que existe. Devitt considera que tal noción de rigidez constituye una adecuada extensión del concepto kripkeano, definido originalmente para términos singulares, en la medida en que permite cumplir la misma función semántica fundamental que aquél: distinguir a los términos que pueden ser explicados mediante una teoría descriptivista de aquéllos para los cuales eso no es posible. De este modo, critica la concepción alternativa de la rigidez para términos generales, basada en la idea de identidad de designación -en la versión de LaPorte -, a la cual acusa de estar comprometida con discutibles tesis metafísicas, incluido un realismo selectivo acerca de los universales. En este trabajo, me propongo defender a esta concepción de sus críticas, para lo cual presento una versión de la misma diferente de la de LaPorte. En mi opinión, la versión propuesta supera además a la definición de rigidez ofrecida por Devitt en el logro de su objetivo principal, a saber, mostrar que algunos términos generales, al igual que la mayor parte de los nombres ordinarios, no pueden ser explicados en términos descriptivistas. (shrink)

A distinction is drawn among predicates, open sentences (or open formulas), and general terms, including general-term phrases. Attaching a copula, perhaps together with an article, to a general term yields a predicate. Predicates can also be obtained through lambda-abstraction on an open sentence. The issue of designation and semantic content for each type of general expression is investigated. It is argued that the designatum of a general term is a universal, e.g., a kind, whereas the designatum of a predicate is (...) a class (or its characteristic function) and the designatum of an open sentence is a truth-value. Predicates and open sentences are therefore typically non-rigid designators. It is argued further that certain general terms, including phrases, are invariably rigid designators, whereas certain others (general definite descriptions) are typically non-rigid. Suitable semantic contents for predicates, open sentences, and general terms are proposed. Consequences for the thesis of compositionality are drawn. (shrink)

The simple proposal for a characterization of general term rigidity is in terms of sameness of designation in very possible world. Critics like Schwartz (2002) and Soames (2002) have argued that such a proposal would trivialize rigidity for general terms. Martí (2004) claims that the objection rests on the failure to distinguish what is expressed by a general term and the property designated. I argue here against such a response by showing that the trivialization problem reappears even if one pays (...) attention to such a distinction. (shrink)

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

Although it is common to claim that certain general terms or kind terms are rigid designators and that their rigidity helps explain their behavior in modal contexts, it has turned out to be surprisingly difficult to define an adequate notion of rigidity for general terms. Such definitions tend, as argued in particular by Scott Soames, to lead to a type of overgeneralization that leaves the purported rigidity of general terms explanatorily inert. In recent years, several attempts have been made to (...) circumvent the problem, and the present article focuses on a particular and potentially powerful strategy developed by Joseph LaPorte in his recent book Rigid Designation and Theoretical Identities for blocking one of the core inferences in Soames’s case against general term rigidity. I argue that the type of response LaPorte promotes is bound to fail; though it might initially appear to circumvent the threat of trivialization described by Soames, it is susceptible to a different and arguably even worse kind of trivialization challenge. In conclusion, Soames’s arguments remain a significant obstacle to identifying a non-trivializing definition of kind term rigidity, and we have good reasons to think that an explanation for the modal status of theoretical identity statements must be sought elsewhere. (shrink)

According to the simple proposal, a predicate is rigid iff it signifies the same property across the different possible worlds. The simple proposal has been claimed to suffer from an over-generalization problem. Assume that one can make sense of predicates signifying properties, and assume that trivialization concerns, to the effect that the notion would cover any predicate whatsoever, can be overcome. Still, the proposal would over-generalize, the worry has it, by covering predicates for artifactual, social, or evaluative properties, such as (...) 'is a knife,' 'is a bachelor,' or 'is funny.' In defense, it is argued that rigidity for predicates as characterized plays the appropriate theoretical role, and that the contention that "unnatural" properties are not to be rigidly signified is ungrounded. (shrink)

El presente escrito discute la plausibilidad de la admisión de términos generales rígidos no naturales. Enunciados de identidad teórica que incluyen términos generales rígidos no naturales no expresan necesidad a posteriori: son enunciados analíticos, necesarios y a priori. Sólo los enunciados de identidad que incluyen términos generales rígidos naturales son enunciados necesarios a posteriori. Los problemas de la trivialización y sobre generalización suponen que la aplicación de la rigidez a los términos de clase no natural resta importancia a la rigidez (...) como diferenciador semántico – modal, pero eso solo es así si estos problemas exigen que cualquier término general rígido permita afirmar necesidad a posteriori, lo que es rechazado. Se propone la nominalización de un término general como una vía de solución a la trivialización y la sobregeneralización. Del mismo modo, se descarta una lectura predicativa restrictiva de los términos generales. Finalmente, se explicita el principal caso de términos generales no rígidos: términos descriptivos sintácticamente complejos. (shrink)

Standard Kripke-Putnam semantics is widely taken to entail that theoretical identifications like ‘Brontosauruses are Apatosauruses’ or ‘Gold is 79Au’ are necessary, if true. I offer a new diagnosis as to why this modal consequence ensues. Central to my diagnosis is the concept of a paradigm term. I argue that modal and epistemic peculiarities that are commonly considered as distinctive of natural kind expressions are in fact traits that are shared by paradigm terms in general. Philosophical semantics should broaden its focus (...) from natural kind expressions to paradigm terms. (shrink)

Zatímco v případě otázek rigidity singulárních termínů panuje obecná shoda, v případě rigidity predikátů tomu tak překvapivě není. Záměrem této statě je opřít distinkci rigidní / nerigidní o jasné pojmy, jmenovitě o pojem reference v určité sémantické teorii. V důsledku toho lze podat rigorózní definici pojmu rigidního designátoru individua. Tato definice je pak přímočaře adaptovatelná pro případ pojmu rigidního designátoru třídy individuí (apod.). Tímto je dosaženo nejen obecnosti, ale i vnitřní jednoty teorie rigidity.

It is often thought that a notion of general term rigidity could help explain the particular behavior of natural kind terms in modal contexts. An influential strategy for developing a non-trivial account of general term rigidity appeals to essential properties of the things to which such terms apply. I show that essentialism cannot underpin a notion of rigidity that can play the expected explanatory roles. Essentialists are committed to presuppositions that themselves play those roles without implying essentialism.

It is often thought that some general terms or kind terms, in particular natural kind terms, are rigid designators, and that a properly extended notion of singular-term rigidity can help explain the behaviour of such general terms. In this article, I argue that the only legitimate notion of general-term rigidity is a trivial one and identify some crucial asymmetries between a posteriori necessary truths involving names and a posteriori necessary truths involving general terms. If we pay attention to these asymmetries, (...) it becomes clear that attempts to draw a non-trivial rigid/non-rigid distinction for general terms are bound to fail to offer the explanations we expected. As opposed to singular terms, what is interesting about the behaviour of natural kind terms, even in modal contexts, cannot be accounted for by modal distinctions like rigidity/non-rigidity but must rather track non-modal features. (shrink)

Kripke holds the thesis that identity statements containing natural kind terms are if true, necessarily true; these statements can be denominated theoretical identities. Kripke alleges that the necessity of theoretical identities grounds on the linguistic feature that natural kind terms are rigid designators. Nevertheless, I argue that the conception of natural kind terms as rigid designators, in one of their most natural views, hinders the establishment of the truth of theoretical identities and thus of their necessity. However, in Kripke’s works (...) another proposal, not linguistic but metaphysical, is found to justify the presumed necessity of theoretical identities; it grounds on essentialism concerning natural kinds. In this regard, I question some of Kripke’s main claims, focusing on one of the main examples of theoretical identities put forward by Kripke, i.e., “Water is H2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_2$$\end{document}O”. I challenge his a priori claims concerning what should be the essence of a natural kind like water. Furthermore, I adduce that the character of that theoretical identity is not that claimed by Kripke, since in the term flanking the right side of the identity sign it has to be resorted to the notion of similarity or it should have the form of a disjunction of a cluster of substances. (shrink)