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14Inference as doxastic agency. Part II: Ramifications and refinementsAustralasian Journal of Logic 14 (4): 408-438. 2017.Justification stit logic is a logic for reasoning about proving as a certain kind of activity, namely seeing to it that a proof is publicly available. It merges the semantical analysis of deliberatively seeing-to-it-that from stit theory and the semantics of the epistemic logic with justification from. In this paper, after recalling its language and basic semantical definitions, various ramifications and refinements of justification stit logic are presented and discussed: imposing natural restri…Read more
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14Connexive Logic, Connexivity, and Connexivism: Remarks on TerminologyStudia Logica 112 (1): 1-35. 2023.Over the past ten years, the community researching connexive logics is rapidly growing and a number of papers have been published. However, when it comes to the terminology used in connexive logic, it seems to be not without problems. In this introduction, we aim at making a contribution towards both unifying and reducing the terminology. We hope that this can help making it easier to survey and access the field from outside the community of connexive logicians. Along the way, we will make clear…Read more
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14Advances in Modal Logic, Volume 2: Papers From the Second Aiml Conference, Held at the University of Uppsala, Sweden, October 1998 (edited book)Center for the Study of Language and Inf. 2001.Modal Logic, originally conceived as the logic of necessity and possibility, has developed into a powerful mathematical and computational discipline. It is the main source of formal languages aimed at analyzing complex notions such as common knowledge and formal provability. Modal and modal-like languages also provide us with families of restricted description languages for relational and topological structures; they are being used in many disciplines, ranging from artificial intelligence, compu…Read more
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13On Non-transitive “Identity”In Can Başkent & Thomas Macaulay Ferguson (eds.), Graham Priest on Dialetheism and Paraconsistency, Springer Verlag. pp. 535-553. 2019.Graham Priest takes the relation of identity to be non-transitive. In this paper, we are going to discuss several consequences of identity as a non-transitive relation. We will consider the Henkin-style completeness proof for classical first-order logic with a non-transitive “identity” predicate, Leibniz-identity in Priest’s second-order minimal logic of paradox, and the question whether or not identity of individuals should be defined as Leibniz-identity.
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13The nature of entailment: an informational approachSynthese 198 (S22): 5241-5261. 2019.In this paper we elaborate a conception of entailment based on what we call the Ackermann principle, which explicates valid entailment through a logical connection between sentences depending on their informational content. We reconstruct Dunn’s informational semantics for entailment on the basis of Restall’s approach, with assertion and denial as two independent speech acts, by introducing the notion of a ‘position description’. We show how the machinery of position descriptions can effectively…Read more
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13Tableaux for multi-agent deliberative-stit logicIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 503-520. 1998.
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13On the Provable Contradictions of the Connexive Logics C and C3Journal of Philosophical Logic 52 (5): 1355-1383. 2023.Despite the tendency to be otherwise, some non-classical logics are known to validate formulas that are invalid in classical logic. A subclass of such systems even possesses pairs of a formula and its negation as theorems, without becoming trivial. How should these provable contradictions be understood? The present paper aims to shed light on aspects of this phenomenon by taking as samples the constructive connexive logic C, which is obtained by a simple modification of a system of constructible…Read more
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13Recent Trends in Philosophical Logic (Proceedings of Trends in Logic XI) (edited book)Springer. 2014.This volume presents recent advances in philosophical logic with chapters focusing on non-classical logics, including paraconsistent logics, substructural logics, modal logics of agency and other modal logics. The authors cover themes such as the knowability paradox, tableaux and sequent calculi, natural deduction, definite descriptions, identity, truth, dialetheism and possible worlds semantics. The developments presented here focus on challenging problems in the specification of fundamental ph…Read more
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12Correction to: The nature of entailment: an informational approachSynthese 198 (S22): 5263-5264. 2020.The paragraph starting with “By accepting condition only,...” should be read as follows
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12Dag Prawitz on Proofs and Meaning (edited book)Springer. 2014.This volume is dedicated to Prof. Dag Prawitz and his outstanding contributions to philosophical and mathematical logic. Prawitz's eminent contributions to structural proof theory, or general proof theory, as he calls it, and inference-based meaning theories have been extremely influential in the development of modern proof theory and anti-realistic semantics. In particular, Prawitz is the main author on natural deduction in addition to Gerhard Gentzen, who defined natural deduction in his PhD t…Read more
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12Truth Values. Part IStudia Logica 91 (3): 429-455. 2009.The famous “slingshot argument” developed by Church, Gödel, Quine and Davidson is often considered to be a formally strict proof of the Fregean conception that all true sentences, as well as all false ones, have one and the same denotation, namely their corresponding truth value: the true or the false. In this paper we examine the analysis of the slingshot argument by means of a non-Fregean logic undertaken recently by A.Wóitowicz and put to the test her claim that the slingshot argument is in f…Read more
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11A Note on “A Connexive Conditional”Logos and Episteme 13 (3): 325-328. 2022.In a recent article, Mario Günther presented a conditional that is claimed to be connexive. The aim of this short discussion note is to show that Günther’s claim is not without problems.
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11Review: Review of Modal Logic P. Blackburn, M. de Rijke, Y. Venema: Review of Modal Logic (review)Logic Journal of the IGPL 10 (4): 457-458. 2002.
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10Advances in Modal Logic, Volume 1: Papers From the First Aiml Conference, Held at the Free University of Berlin, 1996 (edited book)Cambridge University Press. 1998.Modal logic originated in philosophy as the logic of necessity and possibility. Now it has reached a high level of mathematical sophistication and has many applications in a variety of disciplines, including theoretical and applied computer science, artificial intelligence, the foundations of mathematics, and natural language syntax and semantics. This volume represents the proceedings of the first international workshop on Advances in Modal Logic, held in Berlin, Germany, October 8-10, 1996. It…Read more
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10Editorial introduction. Special issue on consequence relations and sequent systemsLogic Journal of the IGPL 6 (3): 377-381. 1998.
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10Strong Cut-Elimination for Constant Domain First-Order S5Logic Journal of the IGPL 3 (5): 797-810. 1995.We consider a labelled tableau presentation of constant domain first-order S5 and prove a strong cut-elimination theorem.
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9Tableaux for multi-agent deliberative-stit logicIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 503-520. 1998.
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9Proofs, Disproofs, and Their DualsIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 483-505. 1998.
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8A Note on Synonymy in Proof-Theoretic SemanticsIn Thomas Piecha & Kai F. Wehmeier (eds.), Peter Schroeder-Heister on Proof-Theoretic Semantics, Springer. pp. 339-362. 2024.The topic of identity of proofs was put on the agenda of general (or structural) proof theory at an early stage. The relevant question is: When are the differences between two distinct proofs (understood as linguistic entities, proof figures) of one and the same formula so inessential that it is justified to identify the two proofs? The paper addresses another question: When are the differences between two distinct formulas so inessential that these formulas admit of identical proofs? The questi…Read more
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8Proofs, Disproofs, and Their DualsIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 483-505. 1998.
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8Translation of hypersequents into display sequentsLogic Journal of the IGPL 6 (5): 719-734. 1998.
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8What is Negation? (edited book)Springer. 1999.The properties of negation, in combination with those of other logical operations and structural features of the deductibility relation, serve as gateways among logical systems. Negation therefore plays an important role in selecting logical systems for particular applications. This volume provides a thorough treatment of this concept, based on contributions written by authors from various branches of logic. The resulting 14 research papers address a variety of topics including negation in relev…Read more
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7Displaying Modal LogicSpringer. 1998.The present monograph is a slightly revised version of my Habilitations schrift Proof-theoretic Aspects of Intensional and Non-Classical Logics, successfully defended at Leipzig University, November 1997. It collects work on proof systems for modal and constructive logics I have done over the last few years. The main concern is display logic, a certain refinement of Gentzen's sequent calculus developed by Nuel D. Belnap. This book is far from offering a comprehensive presentation of generalized …Read more
Areas of Specialization
Epistemology |
Logic and Philosophy of Logic |
Areas of Interest
Philosophy of Language |