This article is about Avicenna’s account of syllogisms comprising opposite premises. We examine the applications and the truth conditions of these syllogisms. Finally, we discuss the relation between these syllogisms and the principle of non-contradiction.

Although the Evans argument against vague identity has been much discussed, proposah for blocking it have not so far satisfied general conditions which any solution ought to meet. Moreover, the relation between ontically vague identity and ontic vagueness more generally has not yet been satisfactorily addressed. I advocate a way of resisting the Evans argument which satisfies the conditions. To show how this approach can vindicate particular cases of ontically vague identity, I develop a framework for describing ontic vagueness in (...) general in terms of multiple actualities. This provides aprìncipled approach to ontically vague identity which is unaffected by the Evans argument. (shrink)

If one believes that vagueness is an exclusively representational phenomenon, one faces the problem of the many. In the vicinity of Kilimanjaro, there are many many ‘mountain candidates’ all, apparently, with more-or-less equal claim to be mountains. David Lewis has defended a radical claim: that all the billions of mountain candidates are mountains. This paper argues that the supervaluationist about vagueness should adopt Lewis’ proposal, on pain of losing their best explanation of the seductiveness of the sorites.

Disagreeing with most authors on vagueness, the author proposes a solution that he calls ‘three-valued semantic pluralism’ to the age-old sorites paradox. In essence, it is a three-valued semantics for a first-order vague language with identity with the additional suggestion that a vague language has more than one correct interpretation. Unlike the traditional three-valued approach to a vague language, three-valued semantic pluralism can accommodate the phenomenon of higher-order vagueness and the phenomenon of penumbral connection when equipped with ‘suitable conditionals’. The (...) author also shows that three-valued semantic pluralism is a natural consequence of a restricted form of the Tolerance principle ) and a few related ideas, and argues that ) is well-motivated by considerations about how we learn, teach, and use vague predicates. (shrink)

Some have argued that the vagueness exhibited by geographic names and descriptions such as ‘Albuquerque’, ‘the Outback’, or ‘Mount Everest’ is ultimately ontological: these terms are vague because they refer to vague objects, objects with fuzzy boundaries. I take the opposite stand and hold the view that geographic vagueness is exclusively semantic, or conceptual at large. There is no such thing as a vague mountain. Rather, there are many things where we conceive a mountain to be, each with its precise (...) boundary, and when we say ‘Everest’ we are just being vague as to which thing we are referring to. This paper defends this view against some plausible objections. (shrink)

An outline of the wealth of philosophical material that hides behind the flat world of geographic maps, with special reference to (i) the centrality of the boundary concept, (ii) the problem of vagueness, and (iii) the metaphysical question (if such there be) of the identity and persistence conditions of geographic entities.

I am a friend of supervaluationism. A statement lacks a definite truth value if, and only if, it comes out true on some admissible ways of precisifying the semantics of the relevant vocabulary and false on others. In this paper, I focus on the special case of identity statements. I take it that such statements, too, may occasionally suffer a truth-value gap, including philosophically significant instances. Yet there is a potentially devastating objection that can be raised against the supervaluationist treatment (...) of such cases—in fact two objections. Luckily, both can be resisted. But seeing how requires that we take a closer look at the ontological presuppositions of supervaluationism, allowing for more leeway than is usually supposed. (shrink)

An outline of the wealth of philosophical material that hides behind the flat world of geographic maps, with special reference to (i) the centrality of the boundary concept, (ii) the problem of vagueness, and (iii) the metaphysical question (if such there be) of the identity and persistence conditions of geographic entities. Serves as an introduction to the special issue of "Topoi" (20:2, 2001) on the Philosophy of Geography.

Human cognitive acts are directed towards entities of a wide range of different types. What follows is a new proposal for bringing order into this typological clutter. A categorial scheme for the objects of human cognition should be (1) critical and realistic. Cognitive subjects are liable to error, even to systematic error of the sort that is manifested by believers in the Pantheon of Olympian gods. Thus not all putative object-directed acts should be recognized as having objects of their own. (...) What follows is a categorial scheme that is both critically realistic and comprehensive. Thus it enjoys some of the benefits of linguistic idealism and physicalism, without (or so it is hoped) the corresponding disadvantages of each.The starting point for our categorial scheme is the concept of extended entity. (shrink)

Suppose that all non-qualitative facts are grounded in qualitative facts. I argue that this view naturally comes with a picture in which trans-world identity is indeterminate. But this in turn leads to either pervasive indeterminacy in the non-qualitative, or else contingency in what facts about modality and possible worlds are determinate.

How do we know what other speakers say? Perhaps the most natural view is that we hear a speaker's utterance and infer what was said, drawing on our competence in the syntax and semantics of the language. An alternative view that has emerged in the literature is that native speakers have a non-inferential capacity to perceive the content of speech. Call this the perceptual view. The disagreement here is best understood as an epistemological one about whether our knowledge of what (...) speakers say is epistemically mediated by our linguistic competence. The present paper takes up the question of how we should go about settling this issue. Arguments for the perceptual view generally appeal to the phenomenology of speech comprehension. The present paper develops a line of argument for the perceptual view that draws on evidence from empirical psychology. The evidence suggests that a speaker's core syntactic and semantic competence is typically deployed sub-personally. The point is not just that the competence is tacit or unconscious, but that the person is not the locus of the competence. I argue that standing competence can enter into the grounds for knowledge only if it is subject to a certain sort of epistemic assessment, an assessment that is appropriate only if the person is the locus of that competence. If the person is not the locus of a speaker's core linguistic competence, as the psychological evidence suggests, then that competence does not enter into the grounds for our knowledge of what speakers say. If this line of argument is right, it has implications for the epistemology of perception and for our understanding of how empirical psychology bears on epistemology generally. (shrink)

Weatherson argues that whoever accepts classical logic, standard mereology and the difference between vague objects and any others, should conclude that there are no vague objects. Barnes and Williams claim that a supporter of vague objects who accepts classical logic and standard mereology should recognize that the existence of vague objects implies indeterminate identity. Even though it is not clearly stated, they all seem to be committed to the assumption that reality is ultimately constituted by mereological atoms. This assumption is (...) not granted by standard mereology which instead remains silent on whether reality is atomic or gunky; therefore, I contend that whoever maintains classical logic, standard mereology and the difference between vague objects and any others, is not forced to conclude with Weatherson that there are no vague objects; nor is she compelled to revise her point of view according to Barnes and Williams’s proposal and to accept that the existence of vague objects implies indeterminate identity. (shrink)

Does vagueness underlie the mass/count distinction? My answer is no. I motivate this answer in two ways. First, I argue against Chierchia’s recent attempt to explain the distinction in terms of vagueness. Second, I give a more general argument that no such account will succeed.

One well-known objection to supersubstantivalism is that it is inconsistent with the contingency of location. This paper presents a new objection to supersubstantivalism: it is inconsistent with the vagueness of location. Though contingency and vagueness are formally similar, there are important philosophical differences between the two. As a result, the objection from vague location will be structurally different than the objection from contingent location. The paper explores these differences and then defends the argument that supersubstantivalism is inconsistent with the plausible (...) thesis that it is vague where I am located. (shrink)

I will here present a number of problems concerning the idea that there is ontological vagueness, and the related claim that appeal to this idea can help solve some vagueness-related problems. A theme underlying the discussion will be the distinction between vagueness specifically and indeterminacy more generally (and, relatedly, the distinction between ontological vagueness and ontological indeterminacy). Even if the world is somehow ontologically indeterminate it by no means follows that it is, properly speaking, ontologically vague.1..

Consider a cat on a mat. On the one hand, there seems to be just one cat, but on the other there seem to be many things with as good a claim as anything in the vicinity to being a cat. Hence, the problem of the many. In his ‘Many, but Almost One,’ David Lewis offered two solutions. According to the first, only one of the many is indeed a cat, although it is indeterminate exactly which one. According to the (...) second, the many are all cats, but they are almost identical to each other, and hence they are almost one. For Lewis, the two solutions do not compete with each other but are mutually complementary, as each one can assist the other. This paper has two aims: to give some reasons against the first of these two solutions, but then to defend the second as a self-standing solution from Lewis’s considerations to the contrary. (shrink)

Kilimanjaro is a paradigmatic mountain, if any is. Consider atom Sparky, which is neither determinately part of Kilimanjaro nor determinately not part of it. Let Kilimanjaro(+) be the body of land constituted, in the way mountains are constituted by their constituent atoms, by the atoms that make up Kilimanjaro together with Sparky, and Kilimanjaro(–) the one constituted by those other than Sparky. On the one hand, there seems to be just one mountain in the vicinity of Kilimanjaro. On the other (...) hand, both Kilimanjaro(+) and Kilimanjaro(–)—and indeed many other similar things—seem to have an equal claim to be a mountain: all of them exhibit the grounds for something being a mountain—like being an elevation of the earth’s surface rising abruptly and to a large height from the surrounding level,1 or whathaveyou—; and there seems to be nothing in the vicinity with a better claim. Hence, the problem of the many. (shrink)

We explore the view that Frege's puzzle is a source of straightforward counterexamples to Leibniz's law. Taking this seriously requires us to revise the classical logic of quantifiers and identity; we work out the options, in the context of higher-order logic. The logics we arrive at provide the resources for a straightforward semantics of attitude reports that is consistent with the Millian thesis that the meaning of a name is just the thing it stands for. We provide models to show (...) that some of these logics are non-degenerate. (shrink)

An overview of contemporary part-whole theories, with reference to both their axiomatic developments and their philosophical underpinnings.

We think of a boundary whenever we think of an entity demarcated from its surroundings. There is a boundary (a line) separating Maryland and Pennsylvania. There is a boundary (a circle) isolating the interior of a disc from its exterior. There is a boundary (a surface) enclosing the bulk of this apple. Sometimes the exact location of a boundary is unclear or otherwise controversial (as when you try to trace out the margins of Mount Everest, or even the boundary of (...) your own body). Sometimes the boundary lies skew to any physical discontinuity or qualitative differentiation (as with the border of Wyoming, or the boundary between the upper and lower halves of a homogeneous sphere). But whether sharp or blurry, natural or artificial, for every object there appears to be a boundary that marks it off from the rest of the world. Events, too, have boundaries — at least temporal boundaries. Our lives are bounded by our births and by our deaths; the soccer game began at 3pm sharp and ended with the referee's final whistle at 4:45pm. It is sometimes suggested that even abstract entities, such as concepts or sets, have boundaries of their own, and Wittgenstein could emphatically proclaim that the boundaries of our language are the boundaries of our world. Whether all this boundary talk is coherent, however, and whether it reflects the structure of the world or simply the organizing activity of our mind, are matters of deep philosophical controversy. (shrink)

The dissertation considers both metaphysical and logical issues related to the vagueness of natural language. The principle metaphysical claim is that the vagueness of language is, at least in some cases, a direct result of indeterminacy in the subject matter of the language, rather than any sort of flaw of the language. A limited defense of this claim is given, as well as criticism of alternative views. ;A number of logical issues are addressed. First, the relationship between the notion of (...) determinacy and the idea of an unsharp line is considered, and it is suggested that the relationship is not as simple as it may at first seem, and that the idea of the unsharp line may be irreducible. Next, it is urged that there is a methodological fork in the road for the systematic treatment of vague language, including formal semantics. On one path, we accept certain intuitively puzzling propositions, exemplified by "This is red or it is not the case that this is red, though it is indeterminate which." On the other path, we reject classical principles of reasoning in our own reasoning both in and about vague language. Some limited arguments are given for taking the former path, and a formal system relevant to this path is motivated and discussed. Finally, both the metaphysical and logical work of the prior parts of the dissertation are brought to bear on the subject of the indeterminacy of identity. (shrink)

Schiffer has given an argument against supervaluationist accounts of vagueness, based on reports of vague contents. Suppose that Al tells Bob ‘Ben was there’, pointing to a certain place, and later Bob says, ‘Al said that Ben was there’, pointing in the same direction. According to supervaluationist semantics, Schiffer contends, both Al’s and Bob’s utterances of ‘there’ indeterminately refer to myriad precise regions of space; Al’s utterance is true just in case Ben was in any of those precisely bounded regions (...) of space, and Bob’s is true just in case Al said of each of them that it is where Ben was. However, while the supervaluationist truth-conditions for Al’s utterance might be satisfied, those for Bob’s cannot; for Al didn’t say, of any of those precisely delimited regions of space, that it is where Ben was. In an earlier version of the material presented here (García-Carpintero 2000) I replied to Schiffer’s argument that supervaluationism has an independently well-motivated defense. The response is essentially based on the point that the occurrence of ‘there’ in Bob’s utterance (and of ‘tall’ in Wright’s argument) occurs in indirect discourse, and supervaluationists may allow that it shifts its referent there. Schiffer’s reply to this response shows that it was not made sufficiently clearly. In this paper I will try to improve on that score. In his more recent reply, Schiffer (2000b, 325) dismisses a proposal like the one I will make, mainly because it “undermines … a leading virtue of supervaluationism … its implication that vagueness is … not a feature of the world.” I will argue that my reply does not undermine the fundamental contentions of the supervaluationist account. (shrink)

Ci imbattiamo in un confine ogni volta che pensiamo a un’entità demarcata rispetto a ciò che la circonda. C’è un confine (una superficie) che delimita l’interno di una sfera dal suo esterno; c’è un confine (una frontiera) che separa il Maryland dalla Pennsylvania. Talvolta la collocazione esatta di un confine non è chiara o è in qualche modo controversa (come quando si cerchi di tracciare i limiti del monte Everest, o il confine del nostro corpo). Talaltra il confine non corrisponde (...) a una discontinuità fisica o a una differenziazione qualitativa (come nel caso dei confini del Wyoming, o della demarcazione tra la metà superiore e la metà inferiore di una sfera omogenea). Ma, che sia netto o confuso, naturale o artificiale, sembra esservi per ogni oggetto un confine che lo separa dal resto del mondo. Anche gli eventi hanno confini, quantomeno confini temporali. Le nostre vite sono delimitate dalle nostre nascite e morti; una partita di calcio comincia alle quindici in punto e termina col fischio finale dell’arbitro alle sedici e quarantacinque. E a volte si dice che anche le entità astratte, come i concetti o gli insiemi, hanno dei propri confini. Se tutto questo parlare di confini abbia davvero un senso, e se rifletta la struttura del mondo o solo l’attività organizzatrice del nostro intelletto, è però oggetto di profonda controversia filosofica. (shrink)

In this paper I present some of Robert N. McLaughlin's critique of a truth functional approach to conditionals as it appears in his book On the Logic of Ordinary Conditionals. Based on his criticism I argue that the basic principles of logic together amount to epistemological and metaphysical implications that can only be accepted from a logical atomist perspective. Attempts to account for conditional relations within this philosophical framework will necessarily fail. I thus argue that it is not truth functionality (...) as such that is the problem, but the philosophical foundation of modern logic. (shrink)

A critical survey of the fundamental philosophical issues in the logic and formal ontology of space, with special emphasis on the interplay between mereology (the theory of parthood relations), topology (broadly understood as a theory of qualitative spatial relations such as continuity and contiguity), and the theory of spatial location proper.

Some philosophers have argued that the vagueness exhibited by names and descriptions such as ‘Mount Everest’, ‘Downtown Manhattan’, or ‘that cloud in the sky’ is ultimately ontological: they are vague because they refer to vague objects, objects with fuzzy boundaries. I take the opposite stand and argue for the view that all vagueness is semantic. There is no such thing as a vague mountain. Rather, there are many things where we conceive the mountain to be, each with its precise boundary, (...) and when we say ‘Everest’ we are just being vague as to which thing we are referring to. This paper defends this view against some plausible objections. (shrink)