Open texture is a kind of semantic indeterminacy first systematically studied by Waismann. In this paper, extant definitions of open texture will be compared and contrasted, with a view towards the consequences of open-textured concepts in mathematics. It has been suggested that these would threaten the traditional virtues of proof, primarily the certainty bestowed by proof-possession, and this suggestion will be critically investigated using recent work on informal proof. It will be argued that informal proofs (...) have virtues that mitigate the danger posed by open texture. Moreover, it will be argued that while rigor in the guise of formalisation and axiomatisation might banish open texture from mathematical theories through implicit definition, it can do so only at the cost of restricting the tamed concepts in certain ways. (shrink)

Many of the terms of our language, such as “jar”, are open-textured in the sense that their applicability to novel objects is not entirely determined by their past usage. Many others, such as the verbs “use” and “have”, are schematic in the sense that they have only a very general meaning although on any particular occasion of use they denote some more particular relation. The phenomena of open texture and schematicity constitute a sharp challenge to referential semantics, (...) which assumes that every non-logical term has a definite extension. A different, non-referential approach to formal semantics defines truth as relative to a context and defines contexts as built up from exclusively linguistic entities. For any given utterance of a sentence, there will be one of these contexts that pertains to it. In this framework, open texture and schematicity can be understood as consequences of the complex nature of the pertaining relation between contexts and utterances. (shrink)

The purpose of this article is to explore the extent to which mathematics is subject to open texture and the extent to which mathematics resists open texture. The resistance is tied to the importance of proof and, in particular, rigor, in mathematics.

The article presents a careful analysis of the idea of the “open texture” of empirical concepts and the problems of verification in the way that they were formulated by Friedrich Waismann. The idea of the “open texture” means for Waismann a certain type of a linguistic indeterminacy or a sort of lack of definition, which must be distinguished from, and linked to, another types like vagueness or ambiguity. It is shown that empirical statements are not conclusively (...) verifiable for two different reasons: the incompleteness of description of the material object and the open texture of the terms involved. We cannot conclusively verify statements in which the empirical concepts are used, because we cannot define these concepts in an exhaustive way because of their open texture. Thus, the definition of the concept will be incomplete. Waismann’s approach to definition plays here a key role, and it is directly related to the open texture of concepts. The author proposes interpreting the open texture as an immanent property of the concept, as something that is embedded in it a priori, and which can cause a vagueness. Nevertheless, an open texture must be distinguished form a vagueness. This leads to the conclusion that an open texture is a possibility of vagueness; vagueness can be remedied by giving more accurate rules, open texture cannot. In this sense, the “open texture” of a language allows for a more precise definition of concepts (by adjusting the definition) if appropriate circumstances arise. This justifies the thesis that the argument of the open texture is the ontological basis of the linguistic anti-reductionism of Friedrich Waismann. (shrink)

In this paper, we will survey the different uses of the term algorithm in contemporary legal practice. We will argue that the concept of algorithm currently exhibits a substantial degree of open texture, co-determined by the open texture of the concept of algorithm itself and by the open texture inherent to legal discourse. We will substantiate our argument by virtue of a case study, in which we analyze a recent jurisprudential case where the first (...) and second-degree judges have carved-out contrasting notions of algorithm. We will see that, thanks to our analysis of the open texture of the notion of algorithm in legal language, we can make sense of the different decisions taken by the judges as different contextually-determined sharpenings of the concept of algorithm. Finally, we will draw some general conclusions concerning the use of technical terms in legal instruments that address new technologies, such as the EU AI Act. (shrink)

This edited collection covers Friedrich Waismann's most influential contributions to twentieth-century philosophy of language: his concepts of open texture and language strata, his early criticism of verificationism and the analytic-synthetic distinction, as well as their significance for experimental and legal philosophy. -/- In addition, Waismann's original papers in ethics, metaphysics, epistemology and the philosophy of mathematics are here evaluated. They introduce Waismann's theory of action along with his groundbreaking work on fiction, proper names and Kafka's Trial. -/- Waismann (...) is known as the voice of Ludwig Wittgenstein in the Vienna Circle. At the same time we find in his works a determined critic of logical positivism and ordinary language philosophy, who anticipated much later developments in the analytic tradition and devised his very own vision for its future. (shrink)

In recent times, the exponential growth of sequenced genomes and structural knowledge of proteins, as well as the development of computational tools and controlled vocabularies to deal with this growth, has fueled a demand for conceptual clarification regarding the concept of function in molecular biology. In this article, we will attempt to develop an account of function fit to deal with the conceptual/philosophical problems in that domain, but which can be extended to other areas of biology. To provide this account, (...) we will argue for three theses: (1) some authors have confused metatheoretical issues (about the meaning and application criteria of terms) with metaphysical ones (about teleology); this led them to (2) look for explicit definitions of “function”, in terms of necessary and sufficient criteria of application, in order to make the concept of function eliminable; however, (3) if one leaves metaphysical worries aside and focuses on functional attribution practices, it is more adequate to say that the concept of function has an open texture. That is, that a multiplicity of application criteria is available, none of which is sufficient nor necessary to attribute a function to a trait, and which only in concert form a clear picture. We distinguish this thesis from some usual forms of pluralism. Finally, we will illustrate this account with a historical reconstruction of the ascription of a water transport function to aquaporins. (shrink)

The appearance in 1945 of the idea of the open texture of empirical concepts, which anticipated Friedrich Waismann’s thesis of a many-level-structure of language, led to a re-evaluation of “context”. It widens the sense of context that we are accustomed to mentioning as being Wittgenstein’s conception of meaning in his later philosophy. The new idea Waismann brought into the landscape is how to “clarify the context”, which is in a way a very non-Wittgensteinian question as well as an (...) “explanation of context”, where open texture plays a key role. But despite the amount of literature about open texture, this idea of Waismann is still not properly understood. Open texture must be situated as an obstacle to exhaustiveness of definition for internal reasons not only because of unforeseen conditions that could always arise in the future, but also by virtue of an a priori aspect of the texture of concepts. Thus, the main goal of this paper is to propose an interpretation of open texture as an immanent property of a concept, that is, as something that is underlying its nature. (shrink)

In this paper we discuss a view of the Machine Learning technique called Explanation-Based Learning (EBL) or Explanation-Based Generalization (EBG) as a process for the interpretation of vague concepts in logic-based models of law.The open-textured nature of legal terms is a well-known open problem in the building of knowledge-based legal systems. EBG is a technique which creates generalizations of given examples on the basis of background domain knowledge. We relate these two topics by considering EBG''s domain knowledge as (...) corresponding to statute law rules, and EBG''s training example as corresponding to a precedent case. (shrink)

Just about every theorist holds that vague terms are context-sensitive to some extent. What counts as ?tall?, ?rich?, and ?bald? depends on the ambient comparison class, paradigm cases, and/or the like. To take a stock example, a given person might be tall with respect to European entrepreneurs and downright short with respect to professional basketball players. It is also generally agreed that vagueness remains even after comparison class, paradigm cases, etc. are fixed, and so this context sensitivity does not solve (...) the problems with vague terms. In this paper, I briefly sketch the main features of my broadly contextualist account of vagueness, that of the late Ruth Manor, and that of Agustín Rayo, showing how the three accounts relate to, and reinforce, each other, noting a seeming difference. A key item used to articulate my own view is David Lewis's notion of conversational score. This is used to track which borderline cases have been called in the course of a conversation. Manor alludes to Lewis's notion of accommodation, a key aspect of the kinematics of conversation, and Rayo invokes Stalnaker's notion of common ground. I'll show how the conversational score could be employed to develop and extend their views, showing how vague terms, as they construe them, are (or can be) deployed in conversation, consistent with both the underlying indeterminacy of the terms and normal communicative goals. To help develop all three views further, I invoke Craige Roberts's notion of Retrievability, a tool developed to show how definites, such as definite descriptions, singular pronouns, and proper names, are deployed in conversation, in a Lewis-style scorekeeping framework. This, I think, is exactly the right way to understand conversations in what Manor calls non-sorities situations and, to invoke my own view, in sorites situations as well. (shrink)

Beyond the obvious technical difficulties, human attempts to communicate with hypothetical Extra-Terrestrial Intelligences also present a number of philosophical puzzles. After all, an alien intelligence is likely the closest thing to a Wittgensteinian lion humanity could ever encounter. In this paper I advance a new challenge for the feasibility of communication with extra-terrestrials. The problem I raise is a practical problem that falls out of the history and philosophy of mathematics and the implementation of METI projects—specifically, the semiprime self-decryption schema (...) of the Drake Pictures message strategy. The Drake Pictures strategy presumes that aliens share the concept ‘prime number’ with us, as understanding that concept is necessary to decrypt our message. However, if the concept ‘prime number’ exhibited open texture at any point in its history, it could have developed in a different direction than it did in our history. If that is so, an alien could have the concept ‘prime number’ and still not be capable of decrypting our messages. I argue that this new problem is more trenchant than previous arguments in both the philosophy and SETI literature, such as applications of the aforementioned Lion argument and other concerns about the possibility of long-range communication without the assumption of shared concepts. (shrink)

This new addition to the series New Studies in Practical Philosophy edited by W. D. Hudson is a study of deontic moral judgment, in particular of moral concepts which embody standards for the assessment of claims to right or wrong actions. Three main theses are quite clearly stated. The first thesis concerns the distinctive character of the moral point of view which is irreducible to either logical or factual considerations. The second thesis is that moral judgments claim interpersonal validity in (...) the sense that the speaker makes the implicit claim that every reflective agent who considers the judgment "ought to agree" with the judgment as a correct one. The third thesis pertains to the moral disagreement. It is maintained that moral disagreements are "in principle" decidable, not by way of deductive subsumption under the criteria governing the uses of moral concepts, but by a method of inquiry analogous to that of scientific inquiry involving the use of hypothesis. The author acknowledges his debt to Arthur Prior, J. Kovesi, and M. Polanyi. The book is good in raising questions on the relation between moral inquiry and scientific inquiry, the significance of the open texture of moral terms and its relation to ethical argumentation, and the problem of reconciling differences of moral beliefs in the setting of their connection with nonmoral beliefs.—A. S. C. (shrink)

Kripke, argued like this: it seems possible that E; the appearance can't be explained away as really pertaining to a "presentation" of E; so, pending a different explanation, it is possible that E. Textbook Kripkeans see in the contrast between E and its presentation intimations of a quite general distinction between two sorts of meaning. E's secondary or a posteriori meaning is the set of all worlds w which E, as employed here, truly describes. Its primary or a priori meaning (...) is the set of all w such that if w is actual, then E is true. "Conceivability error" occurs when a primary possibility is mistaken for a secondary one. Textbook Kripkeanism is rejected on the grounds that it makes meaning too modal and modality too much a matter of meaning. (shrink)

An important challenge when creating automatically processable laws concerns open-textured terms. The ability to measure open-texture can assist in determining the feasibility of encoding regulation and where additional legal information is required to properly assess a legal issue or dispute. In this article, we propose a novel conceptualisation of open-texture with the aim of determining the extent of open-textured terms in legal documents. We conceptualise open-texture as a lever whose state is impacted (...) by three types of forces: internal forces (the words within the text themselves), external forces (the resources brought to challenge the definition of words), and lateral forces (the merit of such challenges). We tested part of this conceptualisation with 26 participants by investigating agreement in paired annotators. Five key findings emerged. First, agreement on which words are open-texture within a legal text is possible and statistically significant. Second, agreement is even high at an average inter-rater reliability of 0.7 (Cohen’s kappa). Third, when there is agreement on the words, agreement on the Open-Texture Value is high. Fourth, there is a dependence between the Open-Texture Value and reasons invoked behind open-texture. Fifth, involving only four annotators can yield similar results compared to involving twenty more when it comes to only flagging clauses containing open-texture. We conclude the article by discussing limitations of our experiment and which remaining questions in real life cases are still outstanding. (shrink)

Planning problems arise in law when an individual (or corporation)wants to perform a sequence of actions that raises legal issues. Manylawyers make their living planning transactions, and a system thathelped them to solve these problems would be in demand.The designer of such a system in a common-law domain must addressseveral difficult issues, including the open-textured nature of legal rules,the relationship between legal rules and cases, the adversarial nature ofthe domain, and the role of argument. In addition, the system's design (...) isconstrained by the fact that the intended users are lawyers, and its operation and output must be convenient for lawyers to use.In this article, I describe a system called CHIRON that I have developed to explore solutions to these issues. This system develops simple plans from representations of statutes and cases in the domain of United States personal income tax planning. (shrink)

H. L. A. Hart and the "Open Texture" of Language tries to clarify the writings of both Hart and Friedrich Waismann on "open texture". In Waismann's work, "open texture" referred to the potential vagueness of words under extreme (hypothetical) circumstances. Hart's use of the term was quite different, and his work has been misunderstood because those differences were underestimated. Hart should not be read as basing his argument for judicial discretion on the nature of (...) language; primarily, he was putting forward a policy argument for why rules should be applied in a way which would require that discretion. (shrink)

It is a commonly raised argument against the family resemblance account of concepts that there is no limit to a concept's extension. An account of family resemblance which attempts to provide a solution to this problem by including both similarity among instances and dissimilarity to non-instances has been developed by the philosopher of science Thomas Kuhn. Similar solutions have been hinted at in the literature on family resemblance concepts, but the solution has never received a detailed investigation. I shall provide (...) a reconstruction of Kuhn's theory and argue that his solution necessitates a developmental perspective wchich builds on both the transmission of taxonomies between generations and a progressive development through history. (shrink)

This paper examines how the Barthesian difference between écrivains et écrivants can help analyse H.L.A. Hart’s Open Texture of the law. By comparing literary and judicial interpretation, one is able to better understand how lawyers, judges, and legislators can better interpret, use, and draft legislation and case law. In using concrete examples of legislation with regard to the phrase “cruel and usual”, this paper evaluates different interpretive techniques, uncovering key differences. In particular, it compares what implications the Death (...) of the Author would have on legislation that may be considered as vague, or open-ended. Could this mean the Death of the Legislator? What kind of impact may this have on a democracy’s authority? Ultimately, it is suggested that Barthe’s interpretive literary theories are undesirable when it comes to deciphering legislation. Indeed, more concrete and structured approaches are needed. (shrink)

This book offers a systematized overview of Ian Hacking's work. It presents Hacking’s oeuvre as a network made up of four interconnected key nodes: styles of scientific thinking & doing, probability, making up people, and experimentation and scientific realism. Its central claim is that Michel Foucault’s influence is the underlying thread that runs across the Canadian philosopher’s oeuvre. Foucault’s imprint on Hacking’s work is usually mentioned in relation to styles of scientific reasoning and the human sciences. This research shows that (...) Foucault’s influence can in fact be extended beyond these fields, insofar the underlying interest to the whole corpus of Hacking’s works, namely the analysis of conditions of possibility, is stimulated by the work of the French philosopher. Displacing scientific realism as the central focus of Ian Hacking’s oeuvre opens up a very different landscape, showing, behind the apparent dispersion of his works, the far-reaching interest that amalgamates them: to reveal the historical and situated conditions of possibility for the emergence of scientific objects and concepts. This book shows how Hacking’s deployment concepts such as looping effect, making up people, and interactive kinds, can complement Foucauldian analyses, offering an overarching perspective that can provide a better explanation of the objects of the human sciences and their behaviors. (shrink)

By deepening Austin’s reflections on the ‘open texture’ of empirical concepts, Frederick L. Will defends an ‘externalist’ account of mental content: as human beings we could not think, were we not in fact cognizant of a natural world structured by events and objects with identifiable and repeatable similarities and differences. I explicate and defend Will’s insight by developing a parallel critique of Kant’s and Carnap’s rejections of realism, both of whom cannot account properly for the content of experience. (...) This critique shows that Will has identified a genuinely transcendental basis for defending common-sense realism, without appeal to any high-level theory of knowledge. I then show how Will’s realism undercuts Simon Blackburn’s quasi-realism, Michael Williams’ partial defense of skepticism, John Haldane’s attempt to rehabilitate Aquinas’ account of concepts, and how it augments Crispin Wright’s defense of realism. (shrink)

ABSTRACTIn this paper I investigate how conceptual engineering applies to mathematical concepts in particular. I begin with a discussion of Waismann’s notion of open texture, and compare it to Shapiro’s modern usage of the term. Next I set out the position taken by Lakatos which sees mathematical concepts as dynamic and open to improvement and development, arguing that Waismann’s open texture applies to mathematical concepts too. With the perspective of mathematics as open-textured, I make (...) the case that this allows us to deploy the tools of conceptual engineering in mathematics. I will examine Cappelen’s recent argument that there are no conceptual safe spaces and consider whether mathematics constitutes a counterexample. I argue that it does not, drawing on Haslanger’s distinction between manifest and operative concepts, and applying this in a novel way to set-theoretic foundations. I then set out some of the questions that need to be engaged with to establish mathematics as involving a kind of conceptual engineering. I finish with a case study of how the tools of conceptual engineering will give us a way to progress in the debate between advocates of the Universe view and the Multiverse view in set theory. (shrink)

A representation methodology for knowledge allowing multiple interpretations is described. It is based on the following conception of legal knowledge and its open texture. Since indeterminate, legal knowledge must be adapted to fit the circumstances of the cases to which it is applied. Whether a certain adaptation is lawful or not is measured by metaknowledge. But as this too is indeterminate, its adaptation to the case must be measured by metametaknowledge, etc. This hierarchical model of law is quite (...) well-established and may serve well as a basis for a legal knowledge system. To account for the indeterminacy of law such a system should support the construction of different arguments for and against various interpretations of legal sources. However, automatizing this reasoning fully is unsound since it would imply a restriction to arguments defending interpretations anticipated at programming time. Therefore, the system must be interactive and the user''s knowledge be furnished in a principled way. Contrary to the widespread opinion that classical logic is inadequate for representing open-textured knowledge, the framework outlined herein is given a formalization in first order logic. (shrink)

Ben-Yami presents Wittgenstein’s explicit criticism of the Platonic identification of an explanation with a definition and the alternative forms of explanation he employed. He then discusses a few predecessors of Wittgenstein’s criticisms and the Fregean background against which he wrote. Next, the idea of family resemblance is introduced, and objections answered. Wittgenstein’s endorsement of vagueness and the indeterminacy of sense are presented, as well as the open texture of concepts. Common misunderstandings are addressed along the way. Wittgenstein’s ideas, (...) as is then shown, have far-reaching implications for knowledge of meaning and the nature of logic, and with them to the nature of the philosophical project and its possible achievements. (shrink)

I examine the radical contextualists’ two main arguments for the semantic underdeterminacy thesis, according to which all, or almost all, English sentences lack context-independent truth conditions. I show that both arguments are fallacious. The first argument, which I call the fallacy of the many understandings , mistakenly infers that a sentence S is semantically incomplete from the fact that S can be used to mean different things in different contexts. The second argument, which I call the open texture (...) fallacy , wrongly concludes that a sentence S lacks context-independent truth conditions from the fact that there are circumstances in which the truth value of S would be indeterminate. I do however defend the claim that a certain class of sentences not containing any indexicals do lack context-independent truth conditions, and put forward an argument to that effect. But this argument, as I show, does not generalize to all sentences, and thus fails to support the semantic underdeterminacy thesis. (shrink)

In this article the focus is on the topic of indeterminacy of the sources of law. Indeterminacy in this domain may be a product of a lack of legislative regulation or open texture of law, this analysis of the causes of indeterminacy regarding the sources of law is applied to the Cuban legal system.Resumen:El tema de las fuentes del derecho sigue siendo de primer orden en la ciencia jurídica contemporánea, por lo cual resulta de gran utilidad para los (...) juristas abordar las problemáticas que se generan en torno al mismo. Las causas de indeterminación de las fuentes del derecho —determinadas en unos casos por la falta de regulación por parte del legislador y en otros por la textura abierta del derecho que regula el sistema de fuentes— en el sistema jurídico, es una de dichas problemáticas. El objetivo: analizar las causas de indeterminación de las fuentes del derecho y su expresión en contextos jurídicos como el cubano. (shrink)

This article examines the emergence of casuistical case analysis as a methodological alternative to more theory-driven approaches in bioethics research and education. Focusing on The Abuse of Casuistry by A. Jonsen and S. Toulmin, the article articulates the most characteristic features of this modernday casuistry (e.g., the priority allotted to case interpretation and analogical reasoning over abstract theory, the resemblance of casuistry to common law traditions, the ‘open texture’ of its principles, etc.) and discusses some problems with casuistry (...) as an ‘anti-theoretical’ method. It is argued that casuistry so defined is ‘theory modest’ rather than ‘theory free’ and that ethical theory can still play a significant role in casuistical analysis; that casuistical analyses will encounter conflicting ‘deep’ interpretations of our social practices and institutions, and are therefore unlikely sources of increased social consensus on controversial bioethical questions; that its conventionalism raises questions about casuistry's ability to criticize norms embedded in the societal consensus; and that casuistry's emphasis upon analogical reasoning may tend to reinforce the individualistic nature of much bioethical writing. It is concluded that, notwithstanding these problems, casuistry represents a promising alternative to the regnant model of ‘applied ethics’ (i.e., to the ritualistic invocation of the so-called ‘principles of bioethics’). The pedagogical implications of casuistry are addressed throughout the paper and include the following recommendations: (1) use real cases, (2) make them long, richly detailed and comprehensive, (3) present complex sequences of cases, (4) stress the problem of ‘moral diagnosis’, and (5) be ever mindful of the limits of casuistical analysis. Keywords: casuistry, interpretation, methodology, pedagogy CiteULike Connotea Del.icio.us What's this? (shrink)

The concept of karma is one of the most general and basic for the philosophical traditions of India, one of an interconnected cluster of concepts that form the basic presuppositions of Indian philosophy. And like many general, pervasive, and basic philosophical concepts, the idea of karma exhibits both semantic complexity and a certain fluidity and open texture. That is, the concept may not have a determinate application in all possible cases, it can be fleshed out in quite different (...) ways in different contexts and philosophical traditions, and it should be understood as open in its future applications. Thus, any complete account of the concept of karma must take into consideration its diverse uses across .. (shrink)

Temporal externalists expand Putnam’s and Burge’s semantic externalisms to argue that later uses of words transform the semantic significance of earlier uses. Conflicting intuitions about temporal externalism often turn on different conceptions of linguistic practice, which have mostly not been thematically explicated. I defend a version of temporal externalism that replaces the familiar regularist and normative-regulist conceptions of linguistic practice or use. This alternative identifies practices neither by regularities of use, nor by determinate norms governing their constituent performances, but by (...) the ways those performances bear upon and are accountable to one another. Performances are intelligible as part of a larger pattern of practice, but different performances extend that pattern in partially conflicting ways. The essentially anaphoric concepts of “issues” and “stakes” allow us to talk about how alternative extensions of past performance conflict or otherwise mis-align , and what differences it would make to extend the practice in one way rather than another . The result is to recognize both the interdependence of linguistic performances, and the open texture of concepts, by situating them within broader patterns of discursive interaction with changing circumstances. (shrink)

Apparently illegal cases of animal rescue can be either open or covert: ‘open rescue’ is associated with organizations such as Animal Liberation Victoria and Animal Liberation New South Wales; ‘covert rescue’ is associated with the Animal Liberation Front. While the former seems to qualify non-controversially as civil disobedience I argue that at least some instances of the latter could also qualify as civil disobedience just so long as various norms of civility are satisfied. The case for such a (...) move is defended against objections that covertness is inherently suspect; a failure to accept responsibility; and inconsistent with civil disobedience as a form of communication. Against such objections, the paper emphasizes the importance of respecting the open texture of the concept of civil disobedience if it is to be of continuing relevance against the backdrop of changing forms of non-violent dissent. (shrink)

This thesis is about the nature of proofs in mathematics as it is practiced, contrasting the informal proofs found in practice with formal proofs in formal systems. In the first chapter I present a new argument against the Formalist-Reductionist view that informal proofs are justified as rigorous and correct by corresponding to formal counterparts. The second chapter builds on this to reject arguments from Gödel's paradox and incompleteness theorems to the claim that mathematics is inherently inconsistent, basing my objections on (...) the complexities of the process of formalisation. Chapter 3 looks into the relationship between proofs and the development of the mathematical concepts that feature in them. I deploy Waismann's notion of open texture in the case of mathematical concepts, and discuss both Lakatos and Kneebone's dialectical philosophies of mathematics. I then argue that we can apply work from conceptual engineering to the relationship between formal and informal mathematics. The fourth chapter argues for the importance of mathematical knowledge-how and emphasises the primary role of the activity of proving in securing mathematical knowledge. In the final chapter I develop an account of mathematical knowledge based on virtue epistemology, which I argue provides a better view of proofs and mathematical rigour. (shrink)

Stewart Shapiro's aim in Vagueness in Context is to develop both a philosophical and a formal, model-theoretic account of the meaning, function, and logic of vague terms in an idealized version of a natural language like English. It is a commonplace that the extensions of vague terms vary with such contextual factors as the comparison class and paradigm cases. A person can be tall with respect to male accountants and not tall with respect to professional basketball players. The main feature (...) of Shapiro's account is that the extensions of vague terms also vary in the course of a conversation, even after the external contextual features, such as the comparison class, are fixed. A central thesis is that in some cases, a competent speaker of the language can go either way in the borderline area of a vague predicate without sinning against the meaning of the words and the non-linguistic facts. Shapiro calls this open texture, borrowing the term from Friedrich Waismann.The formal model theory has a similar structure to the supervaluationist approach, employing the notion of a sharpening of a base interpretation. In line with the philosophical account, however, the notion of super-truth does not play a central role in the development of validity. The ultimate goal of the technical aspects of the work is to delimit a plausible notion of logical consequence, and to explore what happens with the sorites paradox.Later chapters deal with what passes for higher-order vagueness - vagueness in the notions of 'determinacy' and 'borderline' - and with vague singular terms, or objects. In each case, the philosophical picture is developed by extending and modifying the original account. This is followed with modifications to the model theory and the central meta-theorems.As Shapiro sees it, vagueness is a linguistic phenomenon, due to the kinds of languages that humans speak. But vagueness is also due to the world we find ourselves in, as we try to communicate features of it to each other. Vagueness is also due to the kinds of beings we are. There is no need to blame the phenomenon on any one of those aspects. (shrink)