Results for 'S4'

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  1. Modal logic S4 as a paraconsistent logic with a topological semantics.Marcelo E. Coniglio & Leonardo Prieto-Sanabria - 2017 - In Caleiro Carlos, Dionisio Francisco, Gouveia Paula, Mateus Paulo & Rasga João (eds.), Logic and Computation: Essays in Honour of Amilcar Sernadas. 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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  2. Embedding Classical Logic in S4.Sophie Nagler - 2019 - Dissertation, Munich Center for Mathematical Philosophy (Mcmp), Lmu Munich
    In this thesis, we will study the embedding of classical first-order logic in first-order S4, which is based on the translation originally introduced in Fitting (1970). The initial main part is dedicated to a detailed model-theoretic proof of the soundness of the embedding. This will follow the proof sketch in Fitting (1970). We will then outline a proof procedure for a proof-theoretic replication of the soundness result. Afterwards, a potential proof of faithfulness of the embedding, read in terms of soundness (...)
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  3. If It's Clear, Then It's Clear That It's Clear, or is It? Higher-Order Vagueness and the S4 Axiom.Susanne Bobzien - 2012 - In B. Morison K. Ierodiakonou (ed.), Episteme, etc.: Essays in honour of Jonathan Barnes. OUP UK.
    The purpose of this paper is to challenge some widespread assumptions about the role of the modal axiom 4 in a theory of vagueness. In the context of vagueness, axiom 4 usually appears as the principle ‘If it is clear (determinate, definite) that A, then it is clear (determinate, definite) that it is clear (determinate, definite) that A’, or, more formally, CA → CCA. We show how in the debate over axiom 4 two different notions of clarity are in play (...)
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  4. McKinsey Algebras and Topological Models of S4.1.Thomas Mormann - manuscript
    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 (...)
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  5. Logical consequence in modal logic II: Some semantic systems for S4.George Weaver - 1974 - Notre Dame Journal of Formal Logic 15:370.
    ABSTRACT: This 1974 paper builds on our 1969 paper (Corcoran-Weaver [2]). Here we present three (modal, sentential) logics which may be thought of as partial systematizations of the semantic and deductive properties of a sentence operator which expresses certain kinds of necessity. The logical truths [sc. tautologies] of these three logics coincide with one another and with those of standard formalizations of Lewis's S5. These logics, when regarded as logistic systems (cf. Corcoran [1], p. 154), are seen to be equivalent; (...)
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  6. Peacocke’s Principle-Based Account of Modality: “Flexibility of Origins” Plus S4.Sonia Roca-Royes - 2006 - Erkenntnis 65 (3):405-426.
    Due to the influence of Nathan Salmon’s views, endorsement of the “flexibility of origins” thesis is often thought to carry a commitment to the denial of S4. This paper rejects the existence of this commitment and examines how Peacocke’s theory of the modal may accommodate flexibility of origins without denying S4. One of the essential features of Peacocke’s account is the identification of the Principles of Possibility, which include the Modal Extension Principle (MEP), and a set of Constitutive Principles. Regarding (...)
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  7. Essence and Necessity.Andreas Ditter - 2022 - Journal of Philosophical Logic 51 (3):653-690.
    What is the relation between metaphysical necessity and essence? This paper defends the view that the relation is one of identity: metaphysical necessity is a special case of essence. My argument consists in showing that the best joint theory of essence and metaphysical necessity is one in which metaphysical necessity is just a special case of essence. The argument is made against the backdrop of a novel, higher-order logic of essence, whose core features are introduced in the first part of (...)
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  8. Contingent Existence and the Reduction of Modality to Essence.Trevor Teitel - 2019 - Mind 128 (509):39-68.
    This paper first argues that we can bring out a tension between the following three popular doctrines: (i) the canonical reduction of metaphysical modality to essence, due to Fine, (ii) contingentism, which says that possibly something could have failed to be something, and (iii) the doctrine that metaphysical modality obeys the modal logic S5. After presenting two such arguments (one from the theorems of S4 and another from the theorems of B), I turn to exploring various conclusions we might draw (...)
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  9. Strengthening Consistency Results in Modal Logic.Samuel Alexander & Arthur Paul Pedersen - 2023 - Tark.
    A fundamental question asked in modal logic is whether a given theory is consistent. But consistent with what? A typical way to address this question identifies a choice of background knowledge axioms (say, S4, D, etc.) and then shows the assumptions codified by the theory in question to be consistent with those background axioms. But determining the specific choice and division of background axioms is, at least sometimes, little more than tradition. This paper introduces generic theories for propositional modal logic (...)
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  10. The Logic of What Might Have Been.Nathan Salmon - 1989 - Philosophical Review 98 (1):3-34.
    The dogma that the propositional logic of metaphysical modality is S5 is rebutted. The author exposes fallacies in standard arguments supporting S5, arguing that propositional metaphysical modal logic is weaker even than both S4 and B, and is instead the minimal and weak metaphysical-modal logic T.
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  11. The Reduction of Necessity to Essence.Andreas Ditter - 2020 - Mind 129 (514):351-380.
    In `Essence and Modality', Kit Fine proposes that for a proposition to be metaphysically necessary is for it to be true in virtue of the nature of all objects whatsoever. Call this view Fine's Thesis. This paper is a study of Fine's Thesis in the context of Fine's logic of essence (LE). Fine himself has offered his most elaborate defense of the thesis in the context of LE. His defense rests on the widely shared assumption that metaphysical necessity obeys the (...)
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  12. The Broadest Necessity.Andrew Bacon - 2018 - Journal of Philosophical Logic 47 (5):733-783.
    In this paper the logic of broad necessity is explored. Definitions of what it means for one modality to be broader than another are formulated, and it is proven, in the context of higher-order logic, that there is a broadest necessity, settling one of the central questions of this investigation. It is shown, moreover, that it is possible to give a reductive analysis of this necessity in extensional language. This relates more generally to a conjecture that it is not possible (...)
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  13. Metaphysical indeterminacy in the multiverse.Claudio Calosi & Jessica Wilson - 2022 - In Valia Allori (ed.), Quantum Mechanics and Fundamentality: Naturalizing Quantum Theory between Scientific Realism and Ontological Indeterminacy. Cham: Springer. pp. 375-395.
    One might suppose that Everettian quantum mechanics (EQM) is inhospitable to metaphysial indeterminacy (MI), given that, as A. Wilson (2020) puts it, "the central idea of EQM is to replace indeterminacy with multiplicity" (77). But as Wilson goes on to suggest, the popular decoherence-based understanding of EQM (henceforth: DEQM) appears to admit of indeterminacy in both world number and world nature, where the latter indeterminacy---our focus here---is plausibly metaphysical. After a brief presentation of DEQM (S1), we bolster the case for (...)
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  14. Evil is not Evidence.Mike Almeida - 2022 - Religious Studies 1 (1):1-9.
    The paper aims to show that, if S5 is the logic of metaphysical necessity, then no state of affairs in any possible world constitutes any non-trivial evidence for or against the existence of the traditional God. There might well be states of affairs in some worlds describing extraordinary goods and extraordinary evils, but it is false that these states of affairs constitute any (non-trivial) evidence for or against the existence of God. The epistemological and metaphysical consequences for philosophical theology of (...)
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  15. Necessity, Theism, and Evidence.Mike Almeida - 2022 - Logique Et Analyse 259 (1):287-307.
    The minimal God exemplifies essential omnipotence, omniscience, and moral perfection, but none of the other properties of the traditional God. I examine the consequences of the minimal God in augmented S5, S4, and Kρσ. The metaphysical consequences for the minimal God in S5 include the impossibility that God—or any other object—might acquire, lose, or exchange an essential property. It is impossible that an essentially divine being might become essentially human, for instance. The epistemological consequences include the impossibility of agnosticism—it is (...)
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  16. On an Intuitionistic Logic for Pragmatics.Gianluigi Bellin, Massimiliano Carrara & Daniele Chiffi - 2018 - Journal of Logic and Computation 50 (28):935–966..
    We reconsider the pragmatic interpretation of intuitionistic logic [21] regarded as a logic of assertions and their justi cations and its relations with classical logic. We recall an extension of this approach to a logic dealing with assertions and obligations, related by a notion of causal implication [14, 45]. We focus on the extension to co-intuitionistic logic, seen as a logic of hypotheses [8, 9, 13] and on polarized bi-intuitionistic logic as a logic of assertions and conjectures: looking at the (...)
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  17. Topological Models of Columnar Vagueness.Thomas Mormann - 2022 - Erkenntnis 87 (2):693 - 716.
    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 (...)
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  18. 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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  19. The Modal Theory Of Pure Identity And Some Related Decision Problems.Harold T. Hodes - 1984 - Mathematical Logic Quarterly 30 (26-29):415-423.
    Relative to any reasonable frame, satisfiability of modal quantificational formulae in which “= ” is the sole predicate is undecidable; but if we restrict attention to satisfiability in structures with the expanding domain property, satisfiability relative to the familiar frames (K, K4, T, S4, B, S5) is decidable. Furthermore, relative to any reasonable frame, satisfiability for modal quantificational formulae with a single monadic predicate is undecidable ; this improves the result of Kripke concerning formulae with two monadic predicates.
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  20. Computational capacity of pyramidal neurons in the cerebral cortex.Danko D. Georgiev, Stefan K. Kolev, Eliahu Cohen & James F. Glazebrook - 2020 - Brain Research 1748:147069.
    The electric activities of cortical pyramidal neurons are supported by structurally stable, morphologically complex axo-dendritic trees. Anatomical differences between axons and dendrites in regard to their length or caliber reflect the underlying functional specializations, for input or output of neural information, respectively. For a proper assessment of the computational capacity of pyramidal neurons, we have analyzed an extensive dataset of three-dimensional digital reconstructions from the NeuroMorphoOrg database, and quantified basic dendritic or axonal morphometric measures in different regions and layers of (...)
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  21. Essentialism vis-à-vis Possibilia, Modal Logic, and Necessitism.Sonia Roca-Royes - 2011 - Philosophy Compass 6 (1):54-64.
    Pace Necessitism – roughly, the view that existence is not contingent – essential properties provide necessary conditions for the existence of objects. Sufficiency properties, by contrast, provide sufficient conditions, and individual essences provide necessary and sufficient conditions. This paper explains how these kinds of properties can be used to illuminate the ontological status of merely possible objects and to construct a respectable possibilist ontology. The paper also reviews two points of interaction between essentialism and modal logic. First, we will briefly (...)
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  22.  52
    Base-extension Semantics for Modal Logic.Eckhardt Timo & Pym David - forthcoming - Logic Journal of the IGPL.
    In proof-theoretic semantics, meaning is based on inference. It may be seen as the mathematical expression of the inferentialist interpretation of logic. Much recent work has focused on base-extension semantics, in which the validity of formulas is given by an inductive definition generated by provability in a ‘base’ of atomic rules. Base-extension semantics for classical and intuitionistic propositional logic have been explored by several authors. In this paper, we develop base-extension semantics for the classical propositional modal systems K, KT , (...)
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  23. Modal Paradox II: Essence and Coherence.Nathan Salmón - 2021 - Philosophical Studies 178 (10):3237-3250.
    Paradoxes of nested modality, like Chisholm’s paradox, rely on S4 or something stronger as the propositional logic of metaphysical modality. Sarah-Jane Leslie’s objection to the resolution of Chisholm’s paradox by means of rejection of S4 modal logic is investigated. A modal notion of essence congenial to Leslie’s objection is clarified. An argument is presented in support of Leslie’s crucial but unsupported assertion that, on pain of inconsistency, an object’s essence is the same in every possible world. A fallacy in the (...)
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  24. The Possibility of Unicorns and Modal Logic.Lee Walters - 2014 - Analytic Philosophy 55 (2):295-305.
    Michael Dummett argues, against Saul Kripke, that there could have been unicorns. He then claims that this possibility shows that the logic of metaphysical modality is not S5, and, in particular, that the B axiom is false. Dummett’s argument against B, however, is invalid. I show that although there are number of ways to repair Dummett’s argument against B, each requires a controversial metaphysical or semantic commitment, and that, regardless of this, the case against B is undermotivated. Dummett’s case is (...)
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  25. An Imaginative Person’s Guide to Objective Modality.Derek Lam - forthcoming - In Amy Kind & Christopher Badura (eds.), Epistemic Uses of Imagination. Routledge.
    Imagination is a source of evidence for objective modality. It is through this epistemic connection that the idea of modality first gains traction in our intellectual life. A proper theory of modality should be able to explain our imagination’s modal epistemic behaviors. This chapter highlights a peculiar asymmetry regarding epistemic defeat for imagination-based modal justification. Whereas imagination-based evidence for possibility cannot be undermined by information about the causal origin of our imaginings, unimaginability-based evidence for impossibility can be undermined by information (...)
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  26. I—Columnar Higher-Order Vagueness, or Vagueness is Higher-Order Vagueness.Susanne Bobzien - 2015 - Aristotelian Society Supplementary Volume 89 (1):61-87.
    Most descriptions of higher-order vagueness in terms of traditional modal logic generate so-called higher-order vagueness paradoxes. The one that doesn't is problematic otherwise. Consequently, the present trend is toward more complex, non-standard theories. However, there is no need for this.In this paper I introduce a theory of higher-order vagueness that is paradox-free and can be expressed in the first-order extension of a normal modal system that is complete with respect to single-domain Kripke-frame semantics. This is the system QS4M+BF+FIN. It corresponds (...)
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  27. Evil and Evidence: A Reply to Bass.Mike Almeida - 2023 - Religious Studies.
    In ‘Evil is Still Evidence: Comments on Almeida’ Robert Bass presents three objections to the central argument (ENE) in my ‘Evil is Not Evidence’. The first objection is that ENE is invalid. According to the second objection, it is a consequence of ENE that there can be no evidence for or against a posteriori necessities. The third objection is that, contrary to ENE, the likelihood of certain necessary identities varies with the evidence we have for them. In this reply I (...)
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  28. Spectres of False Divinity: Hume’s Moral Atheism. [REVIEW]John J. Tilley - 2012 - Journal of the History of Philosophy 50 (2):297-298.
    In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Spectres of False Divinity: Hume’s Moral AtheismJohn J. TilleyThomas Holden. Spectres of False Divinity: Hume’s Moral Atheism. Oxford-New York: Oxford University Press, 2010. Pp. xvi + 246. Cloth, $50.00.Thomas Holden argues that a key element of David Hume’s irreligious agenda is his case for moral atheism. According to Holden, Hume defends (conclusively, Hume believes) not merely weak moral atheism, according to which there is no morally praiseworthy deity, (...)
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