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  1. The Logic of Logical Necessity.Andrew Bacon & Kit Fine - manuscript
    Prior to Kripke's seminal work on the semantics of modal logic, McKinsey offered an alternative interpretation of the necessity operator, inspired by the Bolzano-Tarski notion of logical truth. According to this interpretation, `it is necessary that A' is true just in case every sentence with the same logical form as A is true. In our paper, we investigate this interpretation of the modal operator, resolving some technical questions, and relating it to the logical interpretation of modality and some views in (...)
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  2. An Epistemicist Solution to Curry's Paradox.Hasen Khudairi - manuscript
    This paper targets a series of potential issues for the discussion of, and modal resolution to, the alethic paradoxes advanced by Scharp (2013). I aim, then, to provide a novel, epistemicist treatment to Curry's Paradox. The epistemicist solution that I advance enables the retention of both classical logic and the traditional rules for the alethic predicate: truth-elimination and truth-introduction.
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  3. Logics of Formal Inconsistency Enriched with Replacement: An Algebraic and Modal Account.Walter Carnielli, Marcelo E. Coniglio & David Fuenmayor - forthcoming - Review of Symbolic Logic.
    One of the most expected properties of a logical system is that it can be algebraizable, in the sense that an algebraic counterpart of the deductive machinery could be found. Since the inception of da Costa's paraconsistent calculi, an algebraic equivalent for such systems have been searched. It is known that these systems are non self-extensional (i.e., they do not satisfy the replacement property). More than this, they are not algebraizable in the sense of Blok-Pigozzi. The same negative results hold (...)
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  4. From Ideal Worlds to Ideality.Craig Warmke - forthcoming - Journal of the American Philosophical Association.
    In common treatments of deontic logic, the obligatory is what's true in all deontically ideal possible worlds. In this article, I offer a new semantics for Standard Deontic Logic with Leibnizian intensions rather than possible worlds. Even though the new semantics furnishes models that resemble Venn diagrams, the semantics captures the strong soundness and completeness of Standard Deontic Logic. Since, unlike possible worlds, many Leibnizian intensions are not maximally consistent entities, we can amend the semantics to invalidate the inference rule (...)
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  5. A Philosophically Neutral Semantics for Perception Sentences.Samuele Iaquinto & Giuseppe Spolaore - 2022 - Theoria 88 (3):532–544.
    Jaakko Hintikka proposed treating objectual perception sentences, such as ‘Alice sees Bob’, as de re propositional perception sentences. Esa Saarinen extended Hintikka’s idea to eventive perception sentences, such as ‘Alice sees Bob smile’. These approaches, elegant as they may be, are not philosophically neutral, for they presuppose, controversially, that the content of all perceptual experiences is propositional in nature. The aim of this paper is to propose a formal treatment of objectual and eventive perception sentences that builds on Hintikka’s modal (...)
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  6. The Logic of Sequence Frames.Fabio Lampert - 2022 - Review of Symbolic Logic 15 (1):101-132.
    This paper investigates and develops generalizations of two-dimensional modal logics to any finite dimension. These logics are natural extensions of multidimensional systems known from the literature on logics for a priori knowledge. We prove a completeness theorem for propositional n-dimensional modal logics and show them to be decidable by means of a systematic tableau construction.
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  7. Impossible Worlds, by Francesco Berto and Mark Jago. [REVIEW]Koji Tanaka - 2022 - Mind 131 (521):292-301.
    Book Review of Impossible Worlds, by Francesco Berto and Mark Jago. Oxford: Oxford University Press, 2019.
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  8. A Henkin-Style Completeness Proof for the Modal Logic S5.Bruno Bentzen - 2021 - In Pietro Baroni, Christoph Benzmüller & Yì N. Wáng (eds.), Logic and Argumentation: Fourth International Conference, CLAR 2021, Hangzhou, China, October 20–22. Springer. pp. 459-467.
    This paper presents a recent formalization of a Henkin-style completeness proof for the propositional modal logic S5 using the Lean theorem prover. The proof formalized is close to that of Hughes and Cresswell, but the system, based on a different choice of axioms, is better described as a Mendelson system augmented with axiom schemes for K, T, S4, and B, and the necessitation rule as a rule of inference. The language has the false and implication as the only primitive logical (...)
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  9. Lógica modal megárico-estoica: posibilidad y necesidad como operadores atléticos.Jose Alejandro Fernández Cuesta - 2021 - Human 10.
    In this article we introduce a possible way to interpret the possibility and necessity notions developed within the Megaric-Stoic logic as alethic modal operators. Megaric-Stoic semantics will be introduced as metaphysical background for necessity and possibility definitions and arguments will be offered in order to give up the prevailing interpretations which include ad hoc variables. After proposing the survey of diodoric definitions from relational modal semantics, a series of topics that deserve being revisited from this perspective will be pointed out.
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  10. Tense Logic and Ontology of Time.Avril Styrman - 2021 - Proceedings of the Joint Ontology Workshops 2021 Episode VII: The Bolzano Summer of Knowledge Co-Located with the 12th International Conference on Formal Ontology in Information Systems (FOIS 2021), and the 12th International Conference on Biomedical Onto.
    This work aims to make tense logic a more robust tool for ontologists, philosophers, knowledge engineers and programmers by outlining a fusion of tense logic and ontology of time. In order to make tense logic better understandable, the central formal primitives of standard tense logic are derived as theorems from an informal and intuitive ontology of time. In order to make formulation of temporal propositions easier, temporal operators that were introduced by Georg Henrik von Wright are developed, and mapped to (...)
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  11. Updating Data Semantics.Anthony S. Gillies - 2020 - Mind 129 (513):1-41.
    This paper has three main goals. First, to motivate a puzzle about how ignorance-expressing terms like maybe and if interact: they iterate, and when they do they exhibit scopelessness. Second, to argue that there is an ambiguity in our theoretical toolbox, and that exposing that opens the door to a solution to the puzzle. And third, to explore the reach of that solution. Along the way, the paper highlights a number of pleasing properties of two elegant semantic theories, explores some (...)
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  12. A Decidable Multi-Agent Logic for Reasoning About Actions, Instruments, and Norms.Kees van Berkel, Tim Lyon & Francesco Olivieri - 2020 - In Mehdi Dastani, Huimin Dong & Leon van der Torre (eds.), Logic and Argumentation. pp. 219 - 241.
    We formally introduce a novel, yet ubiquitous, category of norms: norms of instrumentality. Norms of this category describe which actions are obligatory, or prohibited, as instruments for certain purposes. We propose the Logic of Agency and Norms (LAN) that enables reasoning about actions, instrumentality, and normative principles in a multi-agent setting. Leveraging LAN , we formalize norms of instrumentality and compare them to two prevalent norm categories: norms to be and norms to do. Last, we pose principles relating the three (...)
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  13. Swap Structures Semantics for Ivlev-Like Modal Logics.Marcelo E. Coniglio & Ana Claudia Golzio - 2019 - Soft Computing 23 (7):2243-2254.
    In 1988, J. Ivlev proposed some (non-normal) modal systems which are semantically characterized by four-valued non-deterministic matrices in the sense of A. Avron and I. Lev. Swap structures are multialgebras (a.k.a. hyperalgebras) of a special kind, which were introduced in 2016 by W. Carnielli and M. Coniglio in order to give a non-deterministic semantical account for several paraconsistent logics known as logics of formal inconsistency, which are not algebraizable by means of the standard techniques. Each swap structure induces naturally a (...)
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  14. Automating Agential Reasoning: Proof-Calculi and Syntactic Decidability for STIT Logics.Tim Lyon & Kees van Berkel - 2019 - In M. Baldoni, M. Dastani, B. Liao, Y. Sakurai & R. Zalila Wenkstern (eds.), PRIMA 2019: Principles and Practice of Multi-Agent Systems. 93413 Cham, Germany: Springer. pp. 202-218.
    This work provides proof-search algorithms and automated counter-model extraction for a class of STIT logics. With this, we answer an open problem concerning syntactic decision procedures and cut-free calculi for STIT logics. A new class of cut-free complete labelled sequent calculi G3LdmL^m_n, for multi-agent STIT with at most n-many choices, is introduced. We refine the calculi G3LdmL^m_n through the use of propagation rules and demonstrate the admissibility of their structural rules, resulting in auxiliary calculi Ldm^m_nL. In the single-agent case, we (...)
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  15. Cut-Free Calculi and Relational Semantics for Temporal STIT Logics.Tim Lyon & Kees van Berkel - 2019 - In Francesco Calimeri, Nicola Leone & Marco Manna (eds.), Logics in Artificial Intelligence. Springer International Publishing. pp. 803 - 819.
    We present cut-free labelled sequent calculi for a central formalism in logics of agency: STIT logics with temporal operators. These include sequent systems for Ldm , Tstit and Xstit. All calculi presented possess essential structural properties such as contraction- and cut-admissibility. The labelled calculi G3Ldm and G3Tstit are shown sound and complete relative to irreflexive temporal frames. Additionally, we extend current results by showing that also Xstit can be characterized through relational frames, omitting the use of BT+AC frames.
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  16. A Neutral Temporal Deontic STIT Logic.Kees van Berkel & Tim Lyon - 2019 - In P. Blackburn, E. Lorini & M. Guo (eds.), Logic, Rationality, and Interaction. Berlin, Heidelberg: pp. 340-354.
    In this work we answer a long standing request for temporal embeddings of deontic STIT logics by introducing the multi-agent STIT logic TDS . The logic is based upon atemporal utilitarian STIT logic. Yet, the logic presented here will be neutral: instead of committing ourselves to utilitarian theories, we prove the logic TDS sound and complete with respect to relational frames not employing any utilitarian function. We demonstrate how these neutral frames can be transformed into utilitarian temporal frames, while preserving (...)
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  17. Boxes and Diamonds: An Open Introduction to Modal Logic.Richard Zach - 2019 - Open Logic Project.
    A textbook for modal and other intensional logics based on the Open Logic Project. It covers normal modal logics, relational semantics, axiomatic and tableaux proof systems, intuitionistic logic, and counterfactual conditionals.
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  18. Структурно-семантична організація лексико-семантичного мікрополя «повага» в сучасній українській мові.Kateryna Blyzniuk - 2017 - Language: Classic – Modern – Postmodern 3:132-139.
    У статті проаналізовано лексемний і семний склад мікрополя «повага», а також його системну організацію в українській мові. Компоненти значення, що функціонують у мікрополі, відбиваають семантику поваги, пошани щодо об’єкта почуття, яким для лексико-семантичного поля «патріотизм» виступають Батьківщина, власний народ, його закони, традиції, історія тощо.
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  19. Modal Logic S4 as a Paraconsistent Logic with a Topological Semantics.Marcelo E. Coniglio & Leonardo Prieto-Sanabria - 2017 - In Carlos Caleiro, Francisco Dionisio, Paula Gouveia, Paulo Mateus & João Rasga (eds.), Logic and Computation: Essays in Honour of Amilcar Sernadas. London, UK: College Publications. pp. 171-196.
    In this paper the propositional logic LTop is introduced, as an extension of classical propositional logic by adding a paraconsistent negation. This logic has a very natural interpretation in terms of topological models. The logic LTop is nothing more than an alternative presentation of modal logic S4, but in the language of a paraconsistent logic. Moreover, LTop is a logic of formal inconsistency in which the consistency and inconsistency operators have a nice topological interpretation. This constitutes a new proof of (...)
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  20. Perspectival Logic of Acceptance and Rejection.Alessandro Giordani - 2017 - Logique and Analyse:265-283.
    This paper aims at developing a logical theory of perspectival epistemic attitudes. After presenting a standard framework for modeling acceptance, where the epistemic space of an agent coincides with a unique epistemic cell, more complex systems are introduced, which are characterized by the existence of many connected epistemic cells, and different possible attitudes towards a proposition, both positive and negative, are discussed. In doing that, we also propose some interesting ways in which the systems can be interpreted on well known (...)
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  21. Лінгвальне віддзеркалення оцінного ставлення до опонента в контексті перейменувальної кампанії.Olha Kyryliuk - 2017 - Language: Classic – Modern – Postmodern 3:29-35.
    У статті йдеться про особливості мовного віддзеркалення взаємного ставлення учасників дискусії в умовах обговорення суспільно-політичної ситуації. У ході аналізу окреслено основні психологічні прийоми маніпуляцій суспільною думкою за допомогою мовних одиниць. Встановлено екстра- та інтралінгвальні чинники, що впливають на вибір того чи того номінатива.
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  22. A Purely Recombinatorial Puzzle.Fritz Peter - 2017 - Noûs 51 (3):547-564.
    A new puzzle of modal recombination is presented which relies purely on resources of first-order modal logic. It shows that naive recombinatorial reasoning, which has previously been shown to be inconsistent with various assumptions concerning propositions, sets and classes, leads to inconsistency by itself. The context sensitivity of modal expressions is suggested as the source of the puzzle, and it is argued that it gives us reason to reconsider the assumption that the notion of metaphysical necessity is in good standing.
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  23. Basic Action Deontic Logic.Alessandro Giordani & Ilaria Canavotto - 2016 - In O. Roy, T. Allard & W. Malte (eds.), Deontic Logic and Normative Systems. College Publications. pp. 80-92.
    The aim of this paper is to introduce a system of dynamic deontic logic in which the main problems related to the de finition of deontic concepts, especially those emerging from a standard analysis of permission in terms of possibility of doing an action without incurring in a violation of the law, are solved. The basic idea is to introduce two crucial distinctions allowing us to differentiate (i) what is ideal with respect to a given code, which fixes the types (...)
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  24. The Problem of Cross-World Predication.Alexander Kocurek - 2016 - Journal of Philosophical Logic 45 (6):697-742.
    While standard first-order modal logic is quite powerful, it cannot express even very simple sentences like “I could have been taller than I actually am” or “Everyone could have been smarter than they actually are”. These are examples of cross-world predication, whereby objects in one world are related to objects in another world. Extending first-order modal logic to allow for cross-world predication in a motivated way has proven to be notoriously difficult. In this paper, I argue that the standard accounts (...)
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  25. Vagueness & Modality—An Ecumenical Approach.Jon Erling Litland & Juhani Yli-Vakkuri - 2016 - Philosophical Perspectives 30 (1):229-269.
    How does vagueness interact with metaphysical modality and with restrictions of it, such as nomological modality? In particular, how do definiteness, necessity (understood as restricted in some way or not), and actuality interact? This paper proposes a model-theoretic framework for investigating the logic and semantics of that interaction. The framework is put forward in an ecumenical spirit: it is intended to be applicable to all theories of vagueness that express vagueness using a definiteness (or: determinacy) operator. We will show how (...)
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  26. Chalmers, semantiikka ja välttämättömyys.Panu Raatikainen - 2016 - In Mahdollisuus. Helsinki: Suomen Filosofinen Yhdistys.
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  27. Between the Actual and the Trivial World.Maciej Sendłak - 2016 - Organon F: Medzinárodný Časopis Pre Analytickú Filozofiu 23 (2):162-176.
    The subject of this paper is the notion of similarity between the actual and impossible worlds. Many believe that this notion is governed by two rules. Ac-cording to the first rule, every non-trivial world is more similar to the actual world than the trivial world is. The second rule states that every possible world is more similar to the actual world than any impossible world is. The aim of this paper is to challenge both of these rules. We argue that (...)
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  28. Reply to Stalnaker.Timothy Williamson - 2016 - Canadian Journal of Philosophy 46 (4-5):727-734.
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  29. Reply to Yli-Vakkuri.Timothy Williamson - 2016 - Canadian Journal of Philosophy 46 (4-5):839-851.
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  30. Reply to Bacon, Hawthorne and Uzquiano.Timothy Williamson - 2016 - Canadian Journal of Philosophy 46 (4-5):542-547.
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  31. Reply to Fritz.Timothy Williamson - 2016 - Canadian Journal of Philosophy 46 (4-5):610-612.
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  32. Reply to Goodman.Timothy Williamson - 2016 - Canadian Journal of Philosophy 46 (4-5):640-653.
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  33. Epistemicism and Modality.Juhani Yli-Vakkuri - 2016 - Canadian Journal of Philosophy 46 (4-5):803-835.
    What kind of semantics should someone who accepts the epistemicist theory of vagueness defended in Timothy Williamson’s Vagueness (1994) give a definiteness operator? To impose some interesting constraints on acceptable answers to this question, I will assume that the object language also contains a metaphysical necessity operator and a metaphysical actuality operator. I will suggest that the answer is to be found by working within a three-dimensional model theory. I will provide sketches of two ways of extracting an epistemicist semantics (...)
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  34. Williamson on Modality.Juhani Yli-Vakkuri & Mark McCullagh - 2016 - Canadian Journal of Philosophy 46 (4-5):453-851.
    This special issue of the Canadian Journal of Philosophy is dedicated to Timothy Williamson's work on modality. It consists of a new paper by Williamson followed by papers on Williamson's work on modality, with each followed by a reply by Williamson. -/- Contributors: Andrew Bacon, Kit Fine, Peter Fritz, Jeremy Goodman, John Hawthorne, Øystein Linnebo, Ted Sider, Robert Stalnaker, Meghan Sullivan, Gabriel Uzquiano, Barbara Vetter, Timothy Williamson, Juhani Yli-Vakkuri.
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  35. Non-Normal Modalities in Variants of Linear Logic.D. Porello & N. Troquard - 2015 - Journal of Applied Non-Classical Logics 25 (3):229-255.
    This article presents modal versions of resource-conscious logics. We concentrate on extensions of variants of linear logic with one minimal non-normal modality. In earlier work, where we investigated agency in multi-agent systems, we have shown that the results scale up to logics with multiple non-minimal modalities. Here, we start with the language of propositional intuitionistic linear logic without the additive disjunction, to which we add a modality. We provide an interpretation of this language on a class of Kripke resource models (...)
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  36. On Conceiving the Inconsistent.Francesco Berto - 2014 - Proceedings of the Aristotelian Society 114 (1pt1):103-121.
    I present an approach to our conceiving absolute impossibilities—things which obtain at no possible world—in terms of ceteris paribus intentional operators: variably restricted quantifiers on possible and impossible worlds based on world similarity. The explicit content of a representation plays a role similar in some respects to the one of a ceteris paribus conditional antecedent. I discuss how such operators invalidate logical closure for conceivability, and how similarity works when impossible worlds are around. Unlike what happens with ceteris paribus counterfactual (...)
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  37. Possible Worlds for Modal Primitivists.Louis deRosset - 2014 - Journal of Philosophical Logic 43 (1):109-131.
    Among the most remarkable developments in metaphysics since the 1950’s is the explosion of philosophical interest in possible worlds. This paper proposes an explanation of what possible worlds are, and argues that this proposal, the interpreted models conception, should be attractive to anyone who thinks that modal facts are primitive, and so not to be explained in terms of some non-modal notion of “possible world.” I articulate three constraints on any acceptable primitivist explanation of the nature of possible worlds, and (...)
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  38. A New Semantics for Systems of Logic of Essence.Alessandro Giordani - 2014 - Studia Logica 102 (3):411-440.
    The purpose of the present paper is to provide a way of understanding systems of logic of essence by introducing a new semantic framework for them. Three central results are achieved: first, the now standard Fitting semantics for the propositional logic of evidence is adapted in order to provide a new, simplified semantics for the propositional logic of essence; secondly, we show how it is possible to construe the concept of necessary truth explicitly by using the concept of essential truth; (...)
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  39. Quantificational Logic and Empty Names.Andrew Bacon - 2013 - Philosophers' Imprint 13.
    The result of combining classical quantificational logic with modal logic proves necessitism – the claim that necessarily everything is necessarily identical to something. This problem is reflected in the purely quantificational theory by theorems such as ∃x t=x; it is a theorem, for example, that something is identical to Timothy Williamson. The standard way to avoid these consequences is to weaken the theory of quantification to a certain kind of free logic. However, it has often been noted that in order (...)
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  40. Making Sense of Paraconsistent Logic: The Nature of Logic, Classical Logic and Paraconsistent Logic.Koji Tanaka - 2013 - In Francesco Berto, Edwin Mares, Koji Tanaka & Francesco Paoli (eds.), Paraconsistency: Logic and Applications. Springer. pp. 15--25.
    Max Cresswell and Hilary Putnam seem to hold the view, often shared by classical logicians, that paraconsistent logic has not been made sense of, despite its well-developed mathematics. In this paper, I examine the nature of logic in order to understand what it means to make sense of logic. I then show that, just as one can make sense of non-normal modal logics (as Cresswell demonstrates), we can make `sense' of paraconsistent logic. Finally, I turn the tables on classical logicians (...)
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  41. The Adjustment Of Identity: Inquiries Into Logic and Semantics of an Uncertain World.Nijaz Ibrulj - 2012 - Studia Humana 1 (3/4):17-31.
    In this article I present some characteristics of logics and semantics of an uncertain world. I confront two-valued and fuzzy logic. I use Kafka’s novel Process as an example, which is designed as an uncertain context with words which are rigid designators without rigid meaning. That produces an uncertain world of logical and semantical relations. In presentation of problems I introduce basic concepts of Frege’s, Wittgenstein’s, Tarsky’s, Searle’s, Quine’s and Davidson’s philosophy of language. I differ the logical and semantical identification (...)
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  42. Polynomial Ring Calculus for Modal Logics: A New Semantics and Proof Method for Modalities: Polynomial Ring Calculus for Modal Logics.Juan C. Agudelo - 2011 - Review of Symbolic Logic 4 (1):150-170.
    A new proof style adequate for modal logics is defined from the polynomial ring calculus. The new semantics not only expresses truth conditions of modal formulas by means of polynomials, but also permits to perform deductions through polynomial handling. This paper also investigates relationships among the PRC here defined, the algebraic semantics for modal logics, equational logics, the Dijkstra???Scholten equational-proof style, and rewriting systems. The method proposed is throughly exemplified for S 5, and can be easily extended to other modal (...)
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  43. Can Counterfactuals Really Be About Possible Worlds?Stephen Barker - 2011 - Noûs 45 (3):557-576.
    The standard view about counterfactuals is that a counterfactual (A > C) is true if and only if the A-worlds most similar to the actual world @ are C-worlds. I argue that the worlds conception of counterfactuals is wrong. I assume that counterfactuals have non-trivial truth-values under physical determinism. I show that the possible-worlds approach cannot explain many embeddings of the form (P > (Q > R)), which intuitively are perfectly assertable, and which must be true if the contingent falsity (...)
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  44. MacColl’s Modes of Modalities.Fabien Schang - 2011 - Philosophia Scientiae 15:149-188.
    Hugh MacColl is commonly seen as a pioneer of modal and many-valued logic, given his introduction of modalities that go beyond plain truth and falsehood. But a closer examination shows that such a legacy is debatable and should take into account the way in which these modalities proceeded. We argue that, while MacColl devised a modal logic in the broad sense of the word, he did not give rise to a many-valued logic in the strict sense. Rather, his logic is (...)
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  45. Algorithmic Correspondence and Completeness in Modal Logic. V. Recursive Extensions of SQEMA.Willem Conradie, Valentin Goranko & Dimitar Vakarelov - 2010 - Journal of Applied Logic 8 (4):319-333.
    The previously introduced algorithm \sqema\ computes first-order frame equivalents for modal formulae and also proves their canonicity. Here we extend \sqema\ with an additional rule based on a recursive version of Ackermann's lemma, which enables the algorithm to compute local frame equivalents of modal formulae in the extension of first-order logic with monadic least fixed-points \mffo. This computation operates by transforming input formulae into locally frame equivalent ones in the pure fragment of the hybrid mu-calculus. In particular, we prove that (...)
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  46. The Epistemic Inadequacy of Ersatzer Possible World Semantics.Michael J. Shaffer & Jeremy Morris - 2010 - Logique Et Analyse 53:61-76.
    In this paper it is argued that the conjunction of linguistic ersatzism, the ontologically deflationary view that possible worlds are maximal and consistent sets of sentences, and possible world semantics, the view that the meaning of a sentence is the set of possible worlds at which it is true, implies that no actual speaker can effectively use virtually any language to successfully communicate information. This result is based on complexity issues that relate to our finite computational ability to deal with (...)
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  47. Possible Worlds Semantics and the Liar: Reflections on a Problem Posed by Kaplan.Sten Lindström - 2009 - In Joseph Almog & Paolo Leonardi (eds.), The Philosophy of David Kaplan. Oxford University Press.
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  48. Algorithmic Correspondence and Completeness in Modal Logic. IV. Semantic Extensions of SQEMA.Willem Conradie & Valentin Goranko - 2008 - Journal of Applied Non-Classical Logics 18 (2-3):175-211.
    In a previous work we introduced the algorithm \SQEMA\ for computing first-order equivalents and proving canonicity of modal formulae, and thus established a very general correspondence and canonical completeness result. \SQEMA\ is based on transformation rules, the most important of which employs a modal version of a result by Ackermann that enables elimination of an existentially quantified predicate variable in a formula, provided a certain negative polarity condition on that variable is satisfied. In this paper we develop several extensions of (...)
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  49. From Linear to Branching-Time Temporal Logics: Transfer of Semantics and Definability.Valentin Goranko & Alberto Zanardo - 2007 - Logic Journal of the IGPL 15 (1):53-76.
    This paper investigates logical aspects of combining linear orders as semantics for modal and temporal logics, with modalities for possible paths, resulting in a variety of branching time logics over classes of trees. Here we adopt a unified approach to the Priorean, Peircean and Ockhamist semantics for branching time logics, by considering them all as fragments of the latter, obtained as combinations, in various degrees, of languages and semantics for linear time with a modality for possible paths. We then consider (...)
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  50. Elementary Canonical Formulae: Extending Sahlqvist’s Theorem.Valentin Goranko & Dimiter Vakarelov - 2006 - Annals of Pure and Applied Logic 141 (1):180-217.
    We generalize and extend the class of Sahlqvist formulae in arbitrary polyadic modal languages, to the class of so called inductive formulae. To introduce them we use a representation of modal polyadic languages in a combinatorial style and thus, in particular, develop what we believe to be a better syntactic approach to elementary canonical formulae altogether. By generalizing the method of minimal valuations à la Sahlqvist–van Benthem and the topological approach of Sambin and Vaccaro we prove that all inductive formulae (...)
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