The aim of this paper is to show that every topological space gives rise to a wealth of topological models of the modal logic S4.1. The construction of these models is based on the fact that every space defines a Boolean closure algebra (to be called a McKinsey algebra) that neatly reflects the structure of the modal system S4.1. It is shown that the class of topological models based on McKinsey algebras contains a canonical model that can be (...) used to prove a completeness theorem for S4.1. Further, it is shown that the McKinsey algebra MKX of a space X endoewed with an alpha-topologiy satisfies Esakia's GRZ axiom. (shrink)

Abstract. The aim of this paper is to present a topological method for constructing discretizations (tessellations) of conceptual spaces. The method works for a class of topological spaces that the Russian mathematician Pavel Alexandroff defined more than 80 years ago. Alexandroff spaces, as they are called today, have many interesting properties that distinguish them from other topological spaces. In particular, they exhibit a 1-1 correspondence between their specialization orders and their topological structures. Recently, a special type of Alexandroff spaces was (...) used by Ian Rumfitt to elucidate the logic of vague concepts in a new way. According to his approach, conceptual spaces such as the color spectrum give rise to classical systems of concepts that have the structure of atomic Boolean algebras. More precisely, concepts are represented as regular open regions of an underlying conceptual space endowed with a topological structure. Something is subsumed under a concept iff it is represented by an element of the conceptual space that is maximally close to the prototypical element p that defines that concept. This topological representation of concepts comes along with a representation of the familiar logical connectives of Aristotelian syllogistics in terms of natural settheoretical operations that characterize regular open interpretations of classical Boolean propositional logic. In the last 20 years, conceptual spaces have become a popular tool of dealing with a variety of problems in the fields of cognitive psychology, artificial intelligence, linguistics and philosophy, mainly due to the work of Peter Gärdenfors and his collaborators. By using prototypes and metrics of similarity spaces, one obtains geometrical discretizations of conceptual spaces by so-called Voronoi tessellations. These tessellations are extensionally equivalent to topological tessellations that can be constructed for Alexandroff spaces. Thereby, Rumfitt’s and Gärdenfors’s constructions turn out to be special cases of an approach that works for a more general class of spaces, namely, for weakly scattered Alexandroff spaces. This class of spaces provides a convenient framework for conceptual spaces as used in epistemology and related disciplines in general. Alexandroff spaces are useful for elucidating problems related to the logic of vague concepts, in particular they offer a solution of the Sorites paradox (Rumfitt). Further, they provide a semantics for the logic of clearness (Bobzien) that overcomes certain problems of the concept of higher2 order vagueness. Moreover, these spaces help find a natural place for classical syllogistics in the framework of conceptual spaces. The crucial role of order theory for Alexandroff spaces can be used to refine the all-or-nothing distinction between prototypical and nonprototypical stimuli in favor of a more fine-grained gradual distinction between more-orless prototypical elements of conceptual spaces. The greater conceptual flexibility of the topological approach helps avoid some inherent inadequacies of the geometrical approach, for instance, the so-called “thickness problem” (Douven et al.) and problems of selecting a unique metric for similarity spaces. Finally, it is shown that only the Alexandroff account can deal with an issue that is gaining more and more importance for the theory of conceptual spaces, namely, the role that digital conceptual spaces play in the area of artificial intelligence, computer science and related disciplines. Keywords: Conceptual Spaces, Polar Spaces, Alexandroff Spaces, Prototypes, Topological Tessellations, Voronoi Tessellations, Digital Topology. (shrink)

Intuitionistic logic provides an elegant solution to the Sorites Paradox. Its acceptance has been hampered by two factors. First, the lack of an accepted semantics for languages containing vague terms has led even philosophers sympathetic to intuitionism to complain that no explanation has been given of why intuitionistic logic is the correct logic for such languages. Second, switching from classical to intuitionistic logic, while it may help with the Sorites, does not appear to offer any advantages when dealing with the (...) so-called paradoxes of higher-order vagueness. We offer a proposal that makes strides on both issues. We argue that the intuitionist’s characteristic rejection of any third alethic value alongside true and false is best elaborated by taking the normal modal system S4M to be the sentential logic of the operator ‘it is clearly the case that’. S4M opens the way to an account of higher-order vagueness which avoids the paradoxes that have been thought to infect the notion. S4M is one of the modal counterparts of the intuitionistic sentential calculus and we use this fact to explain why IPC is the correct sentential logic to use when reasoning with vague statements. We also show that our key results go through in an intuitionistic version of S4M. Finally, we deploy our analysis to reply to Timothy Williamson’s objections to intuitionistic treatments of vagueness. (shrink)

This paper intends to further the understanding of the formal properties of (higher-order) vagueness by connecting theories of (higher-order) vagueness with more recent work in topology. First, we provide a “translation” of Bobzien's account of columnar higher-order vagueness into the logic of topological spaces. Since columnar vagueness is an essential ingredient of her solution to the Sorites paradox, a central problem of any theory of vagueness comes into contact with the modern mathematical theory of topology. Second, Rumfitt’s recent topological reconstruction (...) of Sainsbury’s theory of prototypically defined concepts is shown to lead to the same class of spaces that characterize Bobzien’s account of columnar vagueness, namely, weakly scattered spaces. Rumfitt calls these spaces polar spaces. They turn out to be closely related to Gärdenfors’ conceptual spaces, which have come to play an ever more important role in cognitive science and related disciplines. Finally, Williamson’s “logic of clarity” is explicated in terms of a generalized topology (“locology”) that can be considered an alternative to standard topology. Arguably, locology has some conceptual advantages over topology with respect to the conceptualization of a boundary and a borderline. Moreover, in Williamson’s logic of clarity, vague concepts with respect to a notion of a locologically inspired notion of a “slim boundary” are (stably) columnar. Thus, Williamson’s logic of clarity also exhibits a certain affinity for columnar vagueness. In sum, a topological perspective is useful for a conceptual elucidation and unification of central aspects of a variety of contemporary accounts of vagueness. (shrink)

nated discussion of the semantics of such verbs. I will call this view.

In my 1991 paper, AAnti-Individualism and Privileged Access,@ I argued that externalism in the philosophy of mind is incompatible with the thesis that we have privileged , nonempirical access to the contents of our own thoughts.¹ One of the most interesting responses to my argument has been that of Martin Davies (1998, 2000, and Chapter _ above) and Crispin Wright (2000 and Chapter _ above), who describe several types of cases to show that warrant for a premise does not always (...) transmit to a known deductive consequence of that premise, and who contend that this fact under-mines my argument for incompatibilism. I will try to show here that the Davies/Wright point about transmission of warrant does not adversely affect my argument. (shrink)

1. The primary evidence and motivation for externalism in the philosophy of mind is provided by the semantic facts that support direct reference theories of names, indexi- cal pronouns, and natural kind terms. But many externalists have forgotten their sem- antic roots, or so I shall contend here. I have become convinced of this by a common reaction among externalists to the main argument of my 1991 paper AAnti-Individual- ism and Privileged Access.@ In that argument, I concluded that externalism is (...) incompat- ible with the principle that we can have privileged, non-empirical knowledge of the contents of our own thoughts. The reaction in question amounts to a dismissive denial of one of my argument=s main premises. This premise, which I defended at length in the paper, is that an externalist thesis regarding a cognitive property should hold that possession of the property by a person _logically_, or _conceptually_, implies the existence of objects external to that person. (shrink)

This is an anthology of ?fteen papers concerning various philosophical problems related to the topic of self-knowledge. All but one of the papers were previously unpublished, and all but two are descendants of presentations at a conference on self-knowledge held at the University of St Andrews in 1995. The collection.

In this admirable book, Scott Soames provides well defended answers to some of the most difficult and important questions in the philosophy of language, and he does so with characteristic thoroughness, clarity, and rigor. The book's title is appropriate, since it does indeed go ‘beyond rigidity’ in many ways. Among other things, Soames does the following in the course of the book. He persuasively argues that the main thesis of Kripke's Naming and Necessity—that ordinary names are rigid designators—can be extended (...) to the more general thesis that simple proper names are synonymous with neither nonrigid nor rigidified descriptions, and so have no descriptive content whatever. He thoroughly defends and places in the context of a larger semantic theory the Millian thesis that the sole semantic contents of most proper names are the names' referents, so that sentences containing such names semantically express singular Russellian propositions. He provides and defends at length an innovative pragmatic account of why substitution of co-referring proper names in cognitive contexts intuitively fails to be truth preserving, even though it seems to follow from the Millian thesis that such substitution must be semantically valid. And he thoroughly and persuasively defends a semantic theory of natural kind terms that explains how, following Kripke and Putnam, theoretical identities involving such terms can express a posteriori necessities, even though on Soames's theory, and contrary to the Kripke-Putnam view, such terms are neither names of natural kinds nor rigid designators in any interesting sense. (shrink)

There is a fairly general consensus that names are Millian (or Russellian) genuine terms, that is, are singular terms whose sole semantic function is to introduce a referent into the propositions expressed by sentences containing the term. This answers the question as to what sort of proposition is expressed by use of sentences containing names. But there is a second serious semantic problem about proper names, that of how the referents of proper names are determined. This is the question that (...) I will discuss in this paper. Various views consistent with Millianism have been proposed as to how the semantic referents of proper names are determined. These views can be classified into (1) description theories and (2) causal theories, but they can also be classified into (3) social practice theories, on which a name’s referent is determined by a social practice involving the referent, and (4) individualistic theories, on which the referent of the use of a name is determined by the speaker’s state of mind. Here I argue against social practice theories of the sorts proposed by Kripke and Evans and in favor of an individualistic approach to name reference. I argue that social practice is irrelevant to determining name reference and that, as a consequence, names have no meanings in natural languages. In the second part of the paper I motivate and propose a new form of individualistic theory which incorporates features of both description theories and Evans’s social practice theory. (shrink)

In “Naming and Necessity” Saul Kripke describes some cases which, he claims, provide counterexamples both to cluster theories and, more generally, to description theories of proper names. My view of these cases is that while they do not provide counterexamples to cluster theories, they can be used to provide evidence against single-description theories. In this paper I shall defend both of the claims involved in my view.

Abstract. On the Direct Reference thesis, proper names are what I call ‘genuine terms’, terms whose sole semantic contributions to the propositions expressed by their use are the terms’ semantic referents. But unless qualified, this thesis implies the false consequence that sentences containing names that fail to refer can never express true or false propositions. (Consider ‘The ancient Greeks worshipped Zeus’, for instance.) I suggest that while names are typically and fundamentally used as genuine terms, there is a small class (...) of names, which I call ‘descriptive names’, whose reference is fixed by commonly associated definite descriptions, and I also suggest that there is an idiom of natural language on which such names can be used as abbreviated definite descriptions in a limited set of sentential contexts, including (1) positive and negative existentials, (2) cognitive ascriptions, and (3) uses of names to talk about myth. Uses of empty descriptive names in such contexts can then be either true or false. Relying on Gregory Currie’s theory of truth in fiction, I also propose an idiom on which fictional names can be used as short for a certain type of description in talk about fiction. Along the way, I provide arguments that names are used as short for descriptions in substantive existential statements as well as in both metamythic and metafictive contexts. I also discuss and criticize alternative views of these matters, including the views of David Braun, Saul Kripke, Peter van Inwagen, and others. (shrink)

Gareth evans has proposed a type of case which shows that kripke's sketch of a causal theory of proper names is in need of modification. Kripke has himself suggested a way in which the modification might proceed, But I argue that this suggestion leads in the wrong direction. I consider a development of kripke's view by michael devitt which may overcome evans' case, But which is shown false by a different sort of case. The latter kind of case also shows (...) that a view of names recently proposed by donnellan is in need of revision. (shrink)

Tyler Burge's (1979) famous thought experiment concerning 'arthritis' is commonly assumed to show that all ascriptions of content to beliefs and other attitudes are dependent for their truth upon facts about the agent's social and linguistic environment. It is also commonly claimed that Burge's argument shows that Putnam's (1975) result regarding natural kind terms applies to all general terms whatever, and hence shows that all such terms have wide meanings.1 But I wish to show here, first, that neither Burge's initial (...) thought experiment nor a second type of example that Burge describes supports either of these conclusions. Second, I will identify the proper conclusion to draw from Burge's discussion and show that this conclusion does not really pose a serious problem for individualism about the mental. And finally, I will argue that Burge's discussion does not in fact provide a conclusive reason for believing its proper conclusion. (shrink)

Searle has proposed a "presupposition-Theory" of proper names in which he maintains that names are not short for descriptions and which, He claims, Solves frege's puzzle as to how an identity-Sentence containing co-Referential names can be informative. Two possible interpretations of searle's view are proposed, And it is argued that neither interpretation can be used to solve frege's puzzle and that, On the most plausible interpretation of his view, Searle is committed to the thesis that names are short for descriptions (...) after all. (shrink)

According to grice, Semantic concepts like meaning and reference should be explicated in terms of the propositional attitudes. In this paper, I argue that grice's program is mistaken in principle. I first motivate a gricean strategy for defining denotation, Or semantic reference, In terms of rules that govern what speakers may refer to with the terms they use. I then express three paradigm gricean theories of denotation and introduce considerations which show that these theories are false.

In this admirable book, Scott Soames provides well defended answers to some of the most difficult and important questions in the philosophy of language, and he does so with characteristic thoroughness, clarity, and rigor. The book's title is appropriate, since it does indeed go ‘beyond rigidity’ in many ways. Among other things, Soames does the following in the course of the book. He persuasively argues that the main thesis of Kripke's Naming and Necessity—that ordinary names are rigid designators—can be extended (...) to the more general thesis that simple proper names are synonymous with neither nonrigid nor rigidified descriptions, and so have no descriptive content whatever. He thoroughly defends and places in the context of a larger semantic theory the Millian thesis that the sole semantic contents of most proper names are the names' referents, so that sentences containing such names semantically express singular Russellian propositions. He provides and defends at length an innovative pragmatic account of why substitution of co-referring proper names in cognitive contexts intuitively fails to be truth preserving, even though it seems to follow from the Millian thesis that such substitution must be semantically valid. And he thoroughly and persuasively defends a semantic theory of natural kind terms that explains how, following Kripke and Putnam, theoretical identities involving such terms can express a posteriori necessities, even though on Soames's theory, and contrary to the Kripke-Putnam view, such terms are neither names of natural kinds nor rigid designators in any interesting sense. (shrink)

We introduce the axiom of the existence of axioms and discuss its implications for logical systems and beyond.

Peirce and Dewey were generally more concerned with the process of scientific activity than purely mathematical work. However, their accounts of knowledge production afford some insights into the epistemology of mathematical postulates, especially definition and axioms. Their rejection of rationalist metaphysics and their emphasis on continuity in inquiry provides the pretext for the pragmatic a priori – hypothetical and operational assumptions whose justification relies on their fruitfulness in the long run. This paper focuses on the application of this idea to (...) the epistemology of definitions and an account of progress in mathematics, although it has broader implications for the study of conceptual change and the function and basis of presuppositions in the sciences. (shrink)

The conclusion of the McKinsey paradox is that certain contingent claims about the external world are knowable a priori. Almost all of the literature on the paradox assumes that this conclusion is unacceptable, and focuses on finding a way of avoiding it. However, there is no consensus that any of these responses work. In this paper I take a different approach, arguing that the conclusion is acceptable. First, I develop our understanding of what Evans calls merely superficially contingent a (...) priori knowledge, and explain why there is no reason to deny that merely superficially contingent a priori knowledge of the external world is possible. I then argue that, properly understood, the conclusion of the McKinsey paradox is that merely superficially contingent knowledge of certain claims about the external world is possible, and so the conclusion is acceptable. Finally, I respond to the two main arguments that the conclusion of the paradox is unacceptable. (shrink)

En décadas recientes se ha considerado que una formulación adecuada del autoconocimiento (AC) debería ser consistente con la tesis del externalismo (E). Michael McKinsey es uno de los personajes que ha enfatizado con mayor ahínco que la conjunción de ambas posturas es inconsistente. En este trabajo defiendo la idea de que las objeciones presentadas por McKinsey no afectan de manera importante la formulación davidsoniana de la autoridad de la primera persona (AC3) en conjunción con (E); señalo, además, que (...) si no pudiera hacerse una reconstrucción à la Davidson de (AC3) desde la postura de McKinsey sería en virtud de las diferencias metodológicas, semánticas, epistemológicas y ontológicas entre ambos autores, y no debido a que esta reconstrucción en sí misma sea incompatible con el externalismo. (shrink)

Spinoza's causal axiom is at the foundation of the Ethics. I motivate, develop and defend a new interpretation that I call the ‘causally restricted interpretation’. This interpretation solves several longstanding puzzles and helps us better understand Spinoza's arguments for some of his most famous doctrines, including his parallelism doctrine and his theory of sense perception. It also undermines a widespread view about the relationship between the three fundamental, undefined notions in Spinoza's metaphysics: causation, conception and inherence.

Axiom weakening is a technique that allows for a fine-grained repair of inconsistent ontologies. Its main advantage is that it repairs on- tologies by making axioms less restrictive rather than by deleting them, employing the use of refinement operators. In this paper, we build on pre- viously introduced axiom weakening for ALC, and make it much more irresistible by extending its definitions to deal with SROIQ, the expressive and decidable description logic underlying OWL 2 DL. We extend the (...) definitions of refinement operator to deal with SROIQ constructs, in particular with role hierarchies, cardinality constraints and nominals, and illustrate its application. Finally, we discuss the problem of termi- nation of an iterated weakening procedure. (shrink)

The Hyperuniverse Programme, introduced in Arrigoni and Friedman (2013), fosters the search for new set-theoretic axioms. In this paper, we present the procedure envisaged by the programme to find new axioms and the conceptual framework behind it. The procedure comes in several steps. Intrinsically motivated axioms are those statements which are suggested by the standard concept of set, i.e. the `maximal iterative concept', and the programme identi fies higher-order statements motivated by the maximal iterative concept. The satisfaction of these statements (...) (H-axioms) in countable transitive models, the collection of which constitutes the `hyperuniverse' (H), has remarkable 1st-order consequences, some of which we review in section 5. (shrink)

In this article I develop an elementary system of axioms for Euclidean geometry. On one hand, the system is based on the symmetry principles which express our a priori ignorant approach to space: all places are the same to us, all directions are the same to us and all units of length we use to create geometric figures are the same to us. On the other hand, through the process of algebraic simplification, this system of axioms directly provides the Weyl’s (...) system of axioms for Euclidean geometry. The system of axioms, together with its a priori interpretation, offers new views to philosophy and pedagogy of mathematics: it supports the thesis that Euclidean geometry is a priori, it supports the thesis that in modern mathematics the Weyl’s system of axioms is dominant to the Euclid’s system because it reflects the a priori underlying symmetries, it gives a new and promising approach to learn geometry which, through the Weyl’s system of axioms, leads from the essential geometric symmetry principles of the mathematical nature directly to modern mathematics. (shrink)

In quantum theory every state can be diagonalized, i.e. decomposed as a convex combination of perfectly distinguishable pure states. This elementary structure plays an ubiquitous role in quantum mechanics, quantum information theory, and quantum statistical mechanics, where it provides the foundation for the notions of majorization and entropy. A natural question then arises: can we reconstruct these notions from purely operational axioms? We address this question in the framework of general probabilistic theories, presenting a set of axioms that guarantee that (...) every state can be diagonalized. The first axiom is Causality, which ensures that the marginal of a bipartite state is well defined. Then, Purity Preservation states that the set of pure transformations is closed under composition. The third axiom is Purification, which allows to assign a pure state to the composition of a system with its environment. Finally, we introduce the axiom of Pure Sharpness, stating that for every system there exists at least one pure effect occurring with unit probability on some state. For theories satisfying our four axioms, we show a constructive algorithm for diagonalizing every given state. The diagonalization result allows us to formulate a majorization criterion that captures the convertibility of states in the operational resource theory of purity, where random reversible transformations are regarded as free operations. (shrink)

Discussion of new axioms for set theory has often focused on conceptions of maximality, and how these might relate to the iterative conception of set. This paper provides critical appraisal of how certain maximality axioms behave on different conceptions of ontology concerning the iterative conception. In particular, we argue that forms of multiversism (the view that any universe of a certain kind can be extended) and actualism (the view that there are universes that cannot be extended in particular ways) face (...) complementary problems. The latter view is unable to use maximality axioms that make use of extensions, where the former has to contend with the existence of extensions violating maximality axioms. An analysis of two kinds of multiversism, a Zermelian form and Skolemite form, leads to the conclusion that the kind of maximality captured by an axiom differs substantially according to background ontology. (shrink)

We present an elementary system of axioms for the geometry of Minkowski spacetime. It strikes a balance between a simple and streamlined set of axioms and the attempt to give a direct formalization in first-order logic of the standard account of Minkowski spacetime in [Maudlin 2012] and [Malament, unpublished]. It is intended for future use in the formalization of physical theories in Minkowski spacetime. The choice of primitives is in the spirit of [Tarski 1959]: a predicate of betwenness and a (...) four place predicate to compare the square of the relativistic intervals. Minkowski spacetime is described as a four dimensional ‘vector space’ that can be decomposed everywhere into a spacelike hyperplane - which obeys the Euclidean axioms in [Tarski and Givant, 1999] - and an orthogonal timelike line. The length of other ‘vectors’ are calculated according to Pythagora’s theorem. We conclude with a Representation Theorem relating models of our system that satisfy second order continuity to the mathematical structure called ‘Minkowski spacetime’ in physics textbooks. (shrink)

Ontology engineering is a hard and error-prone task, in which small changes may lead to errors, or even produce an inconsistent ontology. As ontologies grow in size, the need for automated methods for repairing inconsistencies while preserving as much of the original knowledge as possible increases. Most previous approaches to this task are based on removing a few axioms from the ontology to regain consistency. We propose a new method based on weakening these axioms to make them less restrictive, employing (...) the use of refinement operators. We introduce the theoretical framework for weakening DL ontologies, propose algorithms to repair ontologies based on the framework, and provide an analysis of the computational complexity. Through an empirical analysis made over real-life ontologies, we show that our approach preserves significantly more of the original knowledge of the ontology than removing axioms. (shrink)