When new theoretical terms are introduced into scientific discourse, prevailing accounts imply, analytic or semantic truths come along with them, by way of either definitions or reference-fixing descriptions. But there appear to be few or no analytic truths in scientific theory, which suggests that the prevailing accounts are mistaken. This paper looks to research on the psychology of natural kind concepts to suggest a new account of the introduction of theoretical terms that avoids both definition and reference-fixing description. At the (...) core of the account is a novel psychological process that I call introjection. (shrink)

This book presents a critical analysis of the semantic incommensurability thesis of Thomas Kuhn and Paul Feyerabend. In putting forward the thesis of incommensurability, Kuhn and Feyerabend drew attention to complex issues concerning the phenomenon of conceptual change in science. They raised serious problems about the semantic and logical relations between the content of theories which deploy unlike systems of concepts. Yet few of the more extreme claims associated with incommensurability stand scrutiny. The argument of this book is as follows. (...) The terms of theories with different concepts diverge semantically and the vocabularies of such theories may not be fully intertranslatable. Given the possibility of referential overlap between the terms of conceptually divergent theories, it does not follow that the content of such theories is incomparable. Nor, given the distinction between understanding a language and translation from one language into another, does it follow that the proponents of mutually untranslatable theories are unable to communicate. Neither is it the case that the shift between conceptually divergent theories involves a discontinuous transition between theories which have no common reference or that refer to distinct worlds of their own making. The semantic differences resulting from conceptual variance may be embraced within a thoroughly realist framework on which they are construed as diverse linguistic relations to a fixed and independent reality. -/- The book, which was originally published in 1994, has now been re-issued in the Routledge Revivals series. -/- . (shrink)

Scientific realism is the position that the aim of science is to advance on truth and increase knowledge about observable and unobservable aspects of the mind-independent world which we inhabit. This book articulates and defends that position. In presenting a clear formulation and addressing the major arguments for scientific realism Sankey appeals to philosophers beyond the community of, typically Anglo-American, analytic philosophers of science to appreciate and understand the doctrine. The book emphasizes the epistemological aspects of scientific realism and contains (...) an original solution to the problem of induction that rests on an appeal to the principle of uniformity of nature. (shrink)

In this second paper, I continue my discussion of the problem of reference for scientific realism. First, I consider a final objection to Kitcher’s account of reference, which I generalise to other accounts of reference. Such accounts make attributions of reference by appeal to our pretheoretical intuitions about how true statements ought to be distibuted among the scientific utterances of the past. I argue that in the cases that merit discussion, this strategy fails because our intuitions are unstable. The interesting (...) cases are importantly borderline—it really isn’t clear what we ought to say about how those terms referred. I conclude that in many relevant cases, our grounds for thinking that the theoretical terms of the past referred are matched by our grounds for thinking that they failed to refer, in such a way that deciding on either result is arbitrary and bad news for the realist. In response to this problem, in the second part of the paper I expand upon Field’s account of partial reference to sketch a new way of thinking about the theoretical terms of the past—that they partially referred and partially failed to refer.Keywords: Scientific realism; Reference; Partial denotation; Theoretical terms; Philip Kitcher; Hartry Field. (shrink)

Thomas Samuel Kuhn (1922–1996) is one of the most influential philosophers of science of the twentieth century, perhaps the most influential. His 1962 book The Structure of Scientific Revolutions is one of the most cited academic books of all time. Kuhn’s contribution to the philosophy of science marked not only a break with several key positivist doctrines, but also inaugurated a new style of philosophy of science that brought it closer to the history of science. His account of the development (...) of science held that science enjoys periods of stable growth punctuated by revisionary revolutions. To this thesis, Kuhn added the controversial ‘incommensurability thesis’, that theories from differing periods suffer from certain deep kinds of failure of comparability. (shrink)

It has sometimes been suggested that the so-called new theory of reference (NTR) would provide an alternative picture of meaning and reference which avoids the unwelcome consequences of the meaning-variance thesis and incommesurability. However, numerous philosophers of science have been quite critical towards the idea and NTR in general. It is argued that many of them have an over-simplified and, in part, mistaken understanding of what NTR amounts to. It is submitted that NTR, when correctly understood, can be an important (...) ingredient in the realist toolkit for defending the rationality of science. (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.

Uno de los mayores desafíos que enfrenta el realismo científico es la tesis de la inconmensurabilidad. Consideramos, empero, que la teoría descriptiva causal de la referencia puede determinar si hay alguna continuidad referencial en un cambio de teoría y, específicamente, en qué circunstancias se daría. Tras caracterizarla brevemente, la someteremos a prueba mediante un análisis de caso, a saber, las diferentes caracterizaciones de ‘órbita’ en la astronomía antigua. Ello supone dilucidar cuáles son las propiedades fundamentales por las cuales la órbita (...) ejerce su función. La continuidad referencial se podrá establecer si constatamos que las descripciones causales nucleares de las distintas nociones de órbita, son equivalentes. Este estudio de caso, además, constituye una oportunidad para ahondar en la reflexión: ¿sirve el descriptivismo causal como argumento a favor del realismo científico? ¿Es factible aplicarlo? ¿Cuál es su alcance? Estas y otras preguntas se suscitan a partir del análisis propuesto. (shrink)

Suosituimpia ja vaikutusvaltaisimpia semanttista eksternalismia ja kausaalista viittaamisen teoriaa vastaan käytettyjä strategioita arvioidaan kriittisesti. Tarkemmassa tarkastelussa mikään niistä ei osoittaudu erityisen vakuuttavaksi.

The biological race debate is at an impasse. Issues surrounding hereditarianism aside, there is little empirical disagreement left between race naturalists and anti-realists about biological race. The disagreement is now primarily semantic. This would seem to uniquely qualify philosophers to contribute to the biological race debate. However, philosophers of race are reluctant to focus on semantics, largely because of their worries about the ‘flight to reference’. In this paper, I show how philosophers can contribute to the debate without taking the (...) flight to reference. Drawing on the theory of reference literature and the history of meaning change in science, I develop some criteria for dealing with cases where there is uncertainty about reference. I then apply these criteria to the biological race debate. All of the criteria I develop for eliminating putative kinds are met in the case of ‘race’ as understood by twentieth century geneticist Theodosius Dobzhansky and his contemporary proponents, suggesting that we should eliminate it from our biological ontology. (shrink)

Las teorías de la referencia puramente descriptivistas o causales fracasan a la hora de dar cuenta del modo en que se fija y puede rastrearse la referencia de los términos teóricos. Psillos propuso dos versiones del descriptivismo causal que recogen argu-mentos presentes en defensas previas de dicha posición. Se trata de una teoría mixta que pretende solucionar el problema y acomodarse a intuiciones presentes en enfo-ques alternativos, como el que apela a oraciones de Ramsey. El artículo se propone mostrar la (...) insuficiencia del descriptivismo causal como solución al problema de la referencia de los términos teóricos. (shrink)

This paper considers the issue of translation failure between theories from the perspective of a modified causal theory of reference. It is argued that translation failure between theories is in fact a consequence of such a modified causal theory of reference. The paper attempts to show what is right about the incommensurability thesis from the perspective of such a theory of reference. Since relations of co-reference may obtain between theories in the absence of translation, incomparability of content does not follow (...) from failure of translation. (shrink)

Psillos, Kitcher, and Leplin have defended convergent scientific realism against the pessimistic meta-induction by arguing for the divide et impera strategy. I argue that DEI faces a problem more serious than the pessimistic meta-induction: the problem of accretion. When empirically successful theories and principles are combined, they may no longer make successful predictions or allow for accurate calculations, or the combination otherwise may be an empirical failure. The shift from classical mechanics to the new quantum theory does not reflect the (...) discarding of “idle wheels.” Instead, scientists had to contend with new principles that made classical calculations difficult or impossible, and new results that were inconsistent with classical theorems, and that suggested a new way of conceiving of atomic dynamics. In this shift, reference to atoms and to electrons was preserved, but the underlying causal explanations and descriptions of atoms and electrons changed. I propose that the emphasis on accurate description of causal agents as a virtue of background theory be replaced with Ruetsche’s advocacy of pragmatic, modal resourcefulness. (shrink)

Robustness is often presented as a guideline for distinguishing the true or real from mere appearances or artifacts. Most of recent discussions of robustness have focused on the kind of derivational robustness analysis introduced by Levins, while the related but distinct idea of robustness as multiple accessibility, defended by Wimsatt, has received less attention. In this paper, I argue that the latter kind of robustness, when properly understood, can provide justification for ontological commitments. The idea is that we are justified (...) in believing that things studied by science are real insofar as we have robust evidence for them. I develop and analyze this idea in detail, and based on concrete examples show that it plays an important role in science. Finally, I demonstrate how robustness can be used to clarify the debate on scientific realism and to formulate new arguments. (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)

RESUMEN Las teorías de la referencia puramente descriptivistas o causales fracasan a la hora de dar cuenta del modo en que se fija y puede rastrearse la referencia de los términos teóricos. Psillos propuso dos versiones del descriptivismo causal que recogen argumentos presentes en defensas previas de dicha posición. Se trata de una teoría mixta que pretende solucionar el problema y acomodarse a intuiciones presentes en enfoques alternativos, como el que apela a oraciones de Ramsey. El artículo se propone mostrar (...) la insuficiencia del descriptivismo causal como solución al problema de la referencia de los términos teóricos. ABSTRACT Purely descriptivist or purely causal reference theories fail to account for the manner in which the reference of theoretical terms is fixed and can be traced. S. Psillos proposed two versions of causal descriptivism that take up arguments set forth in previous defenses of said position. His is a mixed theory that attempts to solve the problem by adopting insights from alternative approaches, such as those that resort to Ramsey sentences. The objective of the article is to show the insufficiency of causal descriptivism as a solution to the problem of reference of theoretical terms. (shrink)

In his (1978) and parts of (1993), Philip Kitcher advances a new context-sensitive theory of reference which he applies to abandoned theoretical expression-types, such as Joseph Priestley’s ‘dephlogisticated air’, in order to show that, although qua types they fail to refer uniformly, they nonetheless have referential tokens. This piece offers a critical examination of Kitcher’s theory. After a general investigation into the overall adequacy of Kitcher’s theory as a general account of reference, I focus on the case of abandoned theoretical (...) terms. Kitcher’s theory is meant to be able to evaluate and solve disputes about referential continuity and progress in scientific theorychange. To this end, Kitcher employs the principle of humanity and a notion of the “correct historical explanation” of the production of each expression-token. I argue that the application of the principle of humanity does not offer a principled way to show that the historical actors were involved in different modes of reference when they produced different tokens of an expressiontype. I also suggest that the principle of humanity, coupled with Kitcher’s view that tokens of expression-types may systematically refer to different things, makes conceptual progress too easy and thus uninteresting. (shrink)

Kripke and Putnam have proposed that terms may be introduced to refer to theoretical entities by means of causal descriptions such as 'whatever causes observable effects O'. It is argued that such a reference-fixing definition is ill-formed and that theoretical beliefs must be involved in fixing the reference of a theoretical term. Some examples of reference-fixing are discussed e.g., the term 'electricity'. The Kripke-Putnam theory can not give an account of how terms may be introduced into science and then subsequently (...) be discovered to be non-referring. A modified account of reference-fixing is suggested in which terms such as Gilbert's electric effluvia' and 'phlogiston' can be introduced into science and then be found to lack a reference. (shrink)

Conceptual engineering wants analytic philosophy to be centered around the assessment and improvement of philosophical concepts. But contemporary debates about conceptual engineering do not engage much with the vast literature on conceptual change that exists in philosophy of science. In this article, I argue that an adequate appreciation of the history of philosophy of science can contribute to discussions about conceptual engineering. Specifically, I show that the evolution of debates over scientific conceptual change arguably demonstrates that, contrary to what is (...) commonly assumed in the literature about conceptual engineering, conceptual change is possible within an externalist metasemantics and that any adequate theory of conceptual change should be metasemantically plastic. (shrink)

The theory of concepts advanced in the dissertation aims at accounting for a) how a concept makes successful practice possible, and b) how a scientific concept can be subject to rational change in the course of history. Traditional accounts in the philosophy of science have usually studied concepts in terms only of their reference; their concern is to establish a stability of reference in order to address the incommensurability problem. My discussion, in contrast, suggests that each scientific concept consists of (...) three components of content: 1) reference, 2) inferential role, and 3) the epistemic goal pursued with the concept's use. I argue that in the course of history a concept can change in any of these three components, and that change in one component—including change of reference—can be accounted for as being rational relative to other components, in particular a concept's epistemic goal.This semantic framework is applied to two cases from the history of biology: the homology concept as used in 19th and 20th century biology, and the gene concept as used in different parts of the 20th century. The homology case study argues that the advent of Darwinian evolutionary theory, despite introducing a new definition of homology, did not bring about a new homology concept (distinct from the pre-Darwinian concept) in the 19th century. Nowadays, however, distinct homology concepts are used in systematics/evolutionary biology, in evolutionary developmental biology, and in molecular biology. The emergence of these different homology concepts is explained as occurring in a rational fashion. The gene case study argues that conceptual progress occurred with the transition from the classical to the molecular gene concept, despite a change in reference. In the last two decades, change occurred internal to the molecular gene concept, so that nowadays this concept's usage and reference varies from context to context. I argue that this situation emerged rationally and that the current variation in usage and reference is conducive to biological practice.The dissertation uses ideas and methodological tools from the philosophy of mind and language, the philosophy of science, the history of science, and the psychology of concepts. (shrink)

This is a two tiered investigation. On the one hand, the author presents a systematic account of the philosophy of Hilary Putnam. Being the first comprehensive account to be published in the German-speaking world, the author traces the development of Putnam's realism and philosophy of language and their connections from the early 1950's to 2000. Contrary to the popular view of the discontinuity of Putnam's philosophy, he demonstrates that Putnam maintains certain semantic, pragmatic and epistemological foundations for the rational confirmability, (...) fallibility and self-corrigibility of theoretical knowledge in the empirical sciences as a constant around which many other philosophical assumptions are allowed to vary under critical examination. The resulting view of Putnam's philosophical "position" is decidedly "anti-metaphysical" (contrary to the common association of his philosophy of language with e.g. Kripke's understanding of realism), but not fully "deflationary" (contrary to the reclamation of his criticism of realist metaphysics as Quinean or Rortyan skepticism). On the other hand, the author generalizes, in the second and third parts of the book, Putnam's now famous theory of meaning and reference to develop a framework for the pragmatics of semantic continuity and discontinuity, as well as conceptual change within general terms in empirical settings, like natural kind terms, theoretical terms in natural sciences and commonsense classifications. The third part presents, develops and defends the basic normative premisses as a pragmatic alternative to both, metaphysical (Kripke, Devitt) and sceptical approaches (Quine, Kuhn). The main result here is that many (if not all) preconditions for the semantic bahvior of 'rigid' general terms are not, as usually assumed, ontological in nature, but can be usefully framed as part of the pragmatics of general terms in epistemic practices counting with rational revisability. (shrink)

While purely causal theories of reference have provided a plausible account of the meanings of names and natural kind terms, they cannot handle vacuous theoretical terms. The causal homeostasis theory can but incurs other difficulties. Theories of reference that are intensional and not purely causal tend to be molecularist or holist. Holist theories threaten transtheoretic reference, whereas molecularist theories must supply a principled basis for selecting privileged meaning-determining relations between terms. The causal homeostasis theory is a two-factor molecularist theory, but (...) it fails to provide such a principled basis and collapses into holism. A naturalistic, non-foundationalist holism that deploys strategies of intertheoretic reduction and co-evolutionary pluralism can, however, yield a credible version of transtheoretic reference. (shrink)

A series of explanatory hypotheses are examined under the assumption that the logical structure of function attributions is dependent on the methodological constraints which these hypotheses conform to. Two theses are argued for: (1) Given these methodological constraints, if something has the function of doing Y, then normally it is the only kind of thing that can do Y in that kind of system. (2) What distinguishes function attributions from causal attribution is not that function attributions explain the etiology of (...) the causally efficacious object, as Wright has suggested. The distinction lies rather in that the object's having the effect, which is attributed to it as its function, must figure in the explanation of why it does what it does to achieve that effect. (shrink)

This thesis focuses on models of conceptual change in science and philosophy. In particular, I developed a new bootstrapping methodology for studying conceptual change, centered around the formalization of several popular models of conceptual change and the collective assessment of their improved formal versions via nine evaluative dimensions. Among the models of conceptual change treated in the thesis are Carnap’s explication, Lakatos’ concept-stretching, Toulmin’s conceptual populations, Waismann’s open texture, Mark Wilson’s patches and facades, Sneed’s structuralism, and Paul Thagard’s conceptual revolutions. (...) -/- In order to analyze and compare the conception of conceptual change provided by these different models, I rely on several historical reconstructions of episodes of scientific conceptual change. The historical episodes of scientific change that figure in this work include the emergence of the morphological concept of fish in biological taxonomies, the development of scientific conceptions of temperature, the Church-Turing thesis and related axiomatizations of effective calculability, the history of the concept of polyhedron in 17th and 18th century mathematics, Hamilton’s invention of the quaternions, the history of the pre-abstract group concepts in 18th and 19th century mathematics, the expansion of Newtonian mechanics to viscous fluids forces phenomena, and the chemical revolution. I will also present five different formal and informal improvements of four specific models of conceptual change. I will first present two different improvements of Carnapian explication, a formal and an informal one. My informal improvement of Carnapian explication will consist of a more fine-grained version of the procedure that adds an intermediate, third step to the two steps of Carnapian explication. I will show how this novel three-step version of explication is more suitable than its traditional two-step relative to handle complex cases of explications. My second, formal improvement of Carnapian explication will be a full explication of the concept of explication itself within the theory of conceptual spaces. By virtue of this formal improvement, the whole procedure of explication together with its application procedures and its pragmatic desiderata will be reconceptualized as a precise procedure involving topological and geometrical constraints inside the theory of conceptual spaces. My third improved model of conceptual change will consist of a formal explication of Darwinian models of conceptual change that will make vast use of Godfrey-Smith’s population-based Darwinism for targeting explicitly mathematical conceptual change. My fourth improvement will be dedicated instead to Wilson’s indeterminate model of conceptual change. I will show how Wilson’s very informal framework can be explicated within a modified version of the structuralist model-theoretic reconstructions of scientific theories. Finally, the fifth improved model of conceptual change will be a belief-revision-like logical framework that reconstructs Thagard’s model of conceptual revolution as specific revision and contraction operations that work on conceptual structures. -/- At the end of this work, a general conception of conceptual change in science and philosophy emerges, thanks to the combined action of the three layers of my methodology. This conception takes conceptual change to be a multi-faceted phenomenon centered around the dynamics of groups of concepts. According to this conception, concepts are best reconstructed as plastic and inter-subjective entities equipped with a non-trivial internal structure and subject to a certain degree of localized holism. Furthermore, conceptual dynamics can be judged from a weakly normative perspective, bound to be dependent on shared values and goals. Conceptual change is then best understood, according to this conception, as a ubiquitous phenomenon underlying all of our intellectual activities, from science to ordinary linguistic practices. As such, conceptual change does not pose any particular problem to value-laden notions of scientific progress, objectivity, and realism. At the same time, this conception prompts all our concept-driven intellectual activities, including philosophical and metaphilosophical reflections, to take into serious consideration the phenomenon of conceptual change. An important consequence of this conception, and of the analysis that generated it, is in fact that an adequate understanding of the dynamics of philosophical concepts is a prerequisite for analytic philosophy to develop a realistic and non-idealized depiction of itself and its activities. (shrink)

Kitcher's unification theory of explanation seems to suggest that only the most reductive accounts can legitimately be termed explanatory. This is not what we find in actual scientific practice. In this paper, I attempt to reconcile these ideas. I claim that Kitcher's theory picks out ideal explanations, but that our term explanation is used to cover other accounts that have a certain relationship with the ideal accounts. At times, versions and portions of ideal explanations can also be considered explanatory.

The doctrine of eliminative materialism holds that belief-desire psychology is massively referentially disconnected. We claim, however, that it is not at all obvious what it means to be referentially (dis)connected. The two major accounts of reference both lead to serious difficulties for eliminativism: it seems that elimination is either impossible or omnipresent. We explore the idea that reference fixation is a much more local, partial, and context-dependent process than was supposed by the classical accounts. This pragmatic view suggests that elimination (...) is not the prime model for understanding the complex relations between the mind and brain sciences, and that we have little ground for concluding that in general psychological kinds do not exist. We suggest that reference changes are better seen as continuous rather than completely eliminative. (shrink)

This paper deals with the question of what the most appropriate semantic theory for theoretical terms would be. Traditionally, in the contemporary literature of philosophy of language, there have been two widely held semantic theories: the descriptivist theory and the causal theory. Comparing theoretical terms with natural kind terms, I attempt to show that the causal theory of reference applies to natural kinds owing to certain ontological and epistemological assumptions of natural kinds realism. I argue that there is no reason (...) to keep these assumptions with respect to theoretical entities. Consequently, the causal theory of reference cannot be applied to theoretical terms. Instead, because of certain ontological and epistemological features of theoretical entities, the rival semantic theory, i.e., the descriptivist theory of reference, properly explains how the referents of these terms get fixed and how these terms find their referents. The paper is structured as follows: the first part deals with the question of how a theoretical entity/kind should be distinguished from non-theoretical ones. The second part facilitates a comparison between theoretical kinds and natural kinds to reveal the ontological and epistemological features of each category. In the third part, I argue why the causal theory of reference fails to be a plausible semantic for theoretical terms, and why its rival theory, i.e., the descriptivist theory, provides an appropriate semantic for such terms. Finally, I raise two potential objections regarding my proposed view and try to show how these objections can be overcome. (shrink)

Most philosophers who advocate Scientific Realism endorse also Modal Realism, i.e., assume commitments with objective modality. However, the precise relationship between these positions has been scarcely explored. In this paper I argue that there is an indirect implication from SR to MR. Although the basic thesis of SR does not imply MR, both the main argument for SR and the best realist theory of reference do imply modal commitments.

Contemporary decision theory places crucial emphasis on a family of mathematical results called representation theorems, which relate criteria for evaluating the available options to axioms pertaining to the decision-maker’s preferences. Various claims have been made concerning the reasons for the importance of these results. The goal of this article is to assess their semantic role: representation theorems are purported to provide definitions of the decision-theoretic concepts involved in the evaluation criteria. In particular, this claim shall be examined from the perspective (...) of philosophical theories of the meaning of theoretical terms. (shrink)

La inconmensurabilidad ha ocasionado innumerables controversias y debates. En estos parece ser unánime la interpretación de tal doctrina como una objeción contra la objetividad, el realismo y el progreso científico. Ahora bien, este marco hermenéutico es estrecho para poder comprender la intencionalidad de Paul Feyerabend al formular su doctrina de la inconmensurabilidad. Pues éste no pretendió cuestionar nunca a dichas nociones en cuanto tales sino únicamente mostrar cuán vano resulta ser el intento del neo-positivismo y del racionalismo popperiano por definirlas. (...) En un sentido positivo sostenemos que la inconmensurabilidad en Paul Feyerabend impide o evita retomar, a la hora de definir aquellas nociones, las dialécticas propias del positivismo lógico o del racionalismo crítico. Nuestra intención en este trabajo es exponer su tesis de la inconmensurabilidad como un cuestionamiento a un modo particular de concebir la racionalidad científica y a sus consecuentes nociones de objetividad, progreso y realismo científico. (shrink)

'Material thing' is a two-level concept. In 'first-order extension' - the field of perceptual experience - it is a 'body' that may 'body forth' (show, express) a 'content', like the bodies of persons or pictures. In 'second-order extension' -the physical field or space - it is a 'physical object' whose micro-constitution is the target of the reference of theoretical terms or formulae. As such, it has no content - nothing to 'express'. In the description of a material thing in first-order (...) extension, terms are used whose reference is fixed by ostension. (The picture's pigment is cracked, the person's eyes are blue.) The reference of theoretical terms - to the material thing in second-order extension - is fixed by their interrelationships in the theory. (shrink)