Reference is the relation held to obtain between an expression and what a speaker or thinker intends the expression to represent. Reference is a component of interpretation, the process of giving terms, sentences, and thoughts semantic content. An example of reference in a formal context involves the natural numbers, where each one can be taken to have a corresponding set-theoretic counterpart as its referent. In an informal context reference is exemplified by the relation between a name and the specific name-bearer when a speaker or thinker utters or has the name in mind. Recent debates over reference have concerned the mechanism of reference: How is it that we can refer? In informal contexts, externalists see the reference relation as explicable in terms of the salient causal relations involved in the naming of a thing, or a class of things, and the ensuing causal chains leading to a term’s use. Opponents of this view—internalists—see the reference relation as being conceptually direct, and they take the external approach to rely on untenable metaphysical assumptions about the world’s structure. Moreover, some internalists take the permutability—i.e. the consistent reinterpretation—of certain referential schemes to confound the externalist picture of reference. In this thesis I focus on the reference of theoretical terms in science, and I argue for an externalist treatment of natural kinds and other theoretical elements. Along the way I offer a defense of the externalist’s pre-theoretic metaphysical assumptions and emphasize their central role in the interpretation of scientific languages. The externalist approach acknowledges the necessary constraints on reference-fixing that account for the schemes we employ, and this, I argue, confounds the permutation strategy.

Reference is the relation held to obtain between an expression and what a speaker or thinker intends the expression to represent. Reference is a component of interpretation, the process of giving terms, sentences, and thoughts semantic content. An example of reference in a formal context involves the natural numbers, where each one can be taken to have a corresponding set-theoretic counterpart as its referent. In an informal context reference is exemplified by the relation between a name and the specific name-bearer when a speaker or thinker utters or has the name in mind. Recent debates over reference have concerned the mechanism of reference: How is it that we can refer? In informal contexts, externalists see the reference relation as explicable in terms of the salient causal relations involved in the naming of a thing, or a class of things, and the ensuing causal chains leading to a term’s use. Opponents of this view—internalists—see the reference relation as being conceptually direct, and they take the external approach to rely on untenable metaphysical assumptions about the world’s structure. Moreover, some internalists take the permutability—i.e. the consistent reinterpretation—of certain referential schemes to confound the externalist picture of reference. In this thesis I focus on the reference of theoretical terms in science, and I argue for an externalist treatment of natural kinds and other theoretical elements. Along the way I offer a defense of the externalist’s pre-theoretic metaphysical assumptions and emphasize their central role in the interpretation of scientific languages. The externalist approach acknowledges the necessary constraints on reference-fixing that account for the schemes we employ, and this, I argue, confounds the permutation strategy.

Thomas S. Kuhn claimed that the meanings of scientific terms change in theory changes or in scientific revolutions. In philosophy, meaning change has been taken as the source of a group of problems, such as untranslatability, incommensurability, and referential variance. For this reason, the majority of analytic philosophers have sought to deny that there can be meaning change by focusing on developing a theory of reference that would guarantee referential stability. A number of philosophers have also claimed that Kuhn’s view can be explained by the fact that he accepted and further developed many central tenets of logical empiricism. I maintain that the genesis of Kuhn’s meaning theorising lies in his historical approach and that his view of meaning change is justified. Later in his career he attempted to advance a theory of meaning and can be said to have had limited success in it. What is more, recent cognitive science has unexpectedly managed to shed light on Kuhn’s insights on the organisation of information in the mind, concept learning, and concept definition. Furthermore, although Kuhn’s critique of Putnam’s causal theory of reference has often been dismissed as irrelevant, he has a serious point to address. Kuhn thought that the causal theory that works so well with proper names cannot work with scientific terms. He held that conceptual categories are formed by similarity and dissimilarity relations; therefore, several features and not only one single property are needed for determination of extension. In addition, the causal theory requires universal substances as points of reference of scientific terms. Kuhn was a conceptualist, who held that universals do not exist as mind-independent entities and that mind-dependent family resemblance concepts serve the role of universals. Further, at the beginning of his career, Kuhn was interested in the question of what concepts or ideas are and how they change in their historical context. Although he did not develop his theorising on this issue, I demonstrate that this is a genuine problem in the philosophy of history. Finally, Kuhn argued that scientists cannot have access to truth in history because we cannot transcend our historical niche, and as a consequence, the truth of a belief cannot be a reason for theory choice. Instead of truth, we can rely on justification. I also discuss Kuhn’s idea that problem-solving is the main aim of science and show that this view can be incorporated into coherentist epistemology.

La question à laquelle nous essayons de répondre est : comment les sciences réfèrent à des entités posées comme "réelles", extralinguistiques? Le problème est divisé en deux problématiques : par quels outils linguistiques les sciences assurent-elles la relation référentielle ? A quelles sortes d'entités (individus, classes, classes de classes) les sciences réfèrent-elles ? L'enquête prend la forme d'une analyse linguistique du langage des sciences de la nature. Nous commençons par étudier la structure des classifications. En effet, les lexiques scientifiques sont impliqués dans des systèmes formels, dont nous cherchons à montrer qu'ils sont justiciables de la théorie des types russellienne. Les 2nde et 3ème parties examinent ces lexiques normalisés et codifiés que sont les nomenclatures des sciences naturelles. Nous retraçons d'abord l'origine des nomenclatures biologique et chimique de Linné à Lavoisier. Nous exposons ensuite les débats nomenclaturaux et taxinomiques de la biologie systématique qui se sont déroulés au cours de la 2nde moitié du 20ème siècle. Cette présentation est centrée sur le "type nomenclatural" ou "type porte-nom" qui apparaît comme l'outil méthodologique par excellence par lequel la biologie assure la fonction référentielle des noms des espèces. Nous confrontons enfin le type nomenclatural au "stéréotype" de Putnam et cherchons à déterminer dans quelle mesure la théorie de la référence causale est utile pour clarifier la référence dans les sciences de la nature. / We try to answer the question: How do sciences refer to entities that are deemed "real", extralinguistic? The problem is two-fold: (i) What linguistic tools do sciences use in order to establish and ensure the relation of reference? (ii) What kinds of entities (individuals, classes ans classes of classes) do sciences refer to? Our enquiry takes the form of a linguistic analysis of the language of the natural sciences.The first step consists of a study of the structure of classifications. Actually, the scientific lexicons of entities have a distinctive feature: they are involved in formal systems, that is say, in nomenclatures. We purport to establish that Russell's theory of types provides a sound account of such systems. The 2nd and 3rd parts examine those standarized and codified vocabularies found in sciences. We first relate the origin of biological and chemical nomenclatures from Linnaeus to Lavoisier. We then present the nomenclatural and taxonomic debates conducted in the 2nd half of 20th century in systematic biology. This presentation focuses on the "nomenclatural type" or "name-bearer" as the major methodological tool by which biology fixes the reference of species's names. We conclude by comparing the nomenclatural type with the "stereotype" elaboratd by Putnam in the context of the causal theory of reference, and we try to determinate if and to what extend this theory can be useful in order to throw light on reference in the language of the natural sciences.