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98Between de dicto and de re: De objecto attitudesPhilosophical Quarterly 61 (245): 828-838. 2011.Hintikka's second generation epistemic logic introduces a syntactic device allowing to express independence relations between certain logical constants. De re knowledge attributions can be reformulated in terms of quantifier independence, but the reformulation does not extend to non-factive attitudes like belief. There, formulae with independent quantifiers serve to express a new type of attitude, intermediate between de dicto and de re, called ‘de objecto’: in each possible world compatible wit…Read more
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75The two faces of compatibility with justified beliefsSynthese 193 (1): 15-30. 2016.When discussing knowledge, two relations are of interest: justified doxastic accessibility \ , she is in \ ) and justification equivalence \ exactly the same justified beliefs that she has in \ ). Speaking of compatibility with the agent’s justified beliefs is potentially ambiguous: either of the two relations \ or \ can be meant. I discuss the possibility of identifying the relation of epistemic accessibility \ , she is in \ ) with the union of \ and \ . Neither Gettier’s examples nor the ‘fake…Read more
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75From games to dialogues and backIn Ondrej Majer, Ahti-Veikko Pietarinen & Tero Tulenheimo (eds.), Games: Unifying Logic, Language, and Philosophy, Springer Verlag. pp. 153--208. 2009.
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71Negation and Temporal OntologyAustralasian Journal of Philosophy 89 (1): 101-114. 2011.G. H. von Wright proposed that a temporal interval exemplifies a real contradiction if at least one part of any division of this interval involves the presence of contradictorily related (though non-simultaneous) states. In connection with intervals, two negations must be discerned: 'does not hold at an interval' and 'fails throughout an interval'. Von Wright did not distinguish the two. As a consequence, he made a mistake in indicating how to use his logical symbolism to express the notion of r…Read more
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68Unity, truth and the liar: the modern relevance of medieval solutions to the liar paradox (edited book)Springer. 2008.This volume includes a target paper, taking up the challenge to revive, within a modern (formal) framework, a medieval solution to the Liar Paradox which did ...
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68Remarks on Individuals in Modal ContextsRevue Internationale de Philosophie 250 (4): 383-394. 2009.
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57Hybrid logic meets if modal logicJournal of Logic, Language and Information 18 (4): 559-591. 2009.The hybrid logic and the independence friendly modal logic IFML are compared for their expressive powers. We introduce a logic IFML c having a non-standard syntax and a compositional semantics; in terms of this logic a syntactic fragment of IFML is singled out, denoted IFML c . (In the Appendix it is shown that the game-theoretic semantics of IFML c coincides with the compositional semantics of IFML c .) The hybrid logic is proven to be strictly more expressive than IFML c . By contrast, and the…Read more
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53Games: Unifying Logic, Language, and Philosophy (edited book)Springer Verlag. 2009.This volume presents mathematical game theory as an interface between logic and philosophy.
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45Worlds, times and selves revisitedSynthese 193 (11): 3713-3725. 2016.In Prior’s tense-logical analysis, we can avoid mentioning instants in our language by construing them as propositions of a special kind. Instead of qualifying instants by predicates, we may qualify propositions by modalities. Prior shows that by changing the informal interpretation of our modal-like language, we can similarly attempt to avoid ontological commitments to worlds and even to selves and other bona fide individuals. As he notes, the paraphrasing strategy works too generally to be of …Read more
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43Partially ordered connectives and monadic monotone strict npJournal of Logic, Language and Information 17 (3): 323-344. 2008.Motivated by constraint satisfaction problems, Feder and Vardi (SIAM Journal of Computing, 28, 57–104, 1998) set out to search for fragments of satisfying the dichotomy property: every problem definable in is either in P or else NP-complete. Feder and Vardi considered in this connection two logics, strict NP (or SNP) and monadic, monotone, strict NP without inequalities (or MMSNP). The former consists of formulas of the form , where is a quantifier-free formula in a relational vocabulary; and th…Read more
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36Objects and Modalities: A Study in the Semantics of Modal LogicSpringer Verlag. 2017.This book develops a novel generalization of possible world semantics, called ‘world line semantics’, which recognizes worlds and links between world-bound objects (world lines) as mutually independent aspects of modal semantics. Addressing a wide range of questions vital for contemporary debates in logic and philosophy of language and offering new tools for theoretical linguistics and knowledge representation, the book proposes a radically new paradigm in modal semantics. This framework is moti…Read more
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34IF Modal Logic and Classical NegationStudia Logica 102 (1): 41-66. 2014.The present paper provides novel results on the model theory of Independence friendly modal logic. We concentrate on its particularly well-behaved fragment that was introduced in Tulenheimo and Sevenster (Advances in Modal Logic, 2006). Here we refer to this fragment as ‘Simple IF modal logic’ (IFML s ). A model-theoretic criterion is presented which serves to tell when a formula of IFML s is not equivalent to any formula of basic modal logic (ML). We generalize the notion of bisimulation famili…Read more
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33Sur les « opérateurs rétrogrades »Philosophia Scientiae 8 (2): 145-160. 2004.Une logique d’« opérateurs rétrogrades » (OR) est définie en utilisant des jeux sémantiques, joués sur des modèles à deux dimensions, l’une pour le temps, l’autre pour les scénarios épistémiques. On démontre que l’expressivité de OR est plus grande que celle de la logique de base des attitudes propositionnelles (AL). De plus, on établit que les pouvoirs expressifs de OR et la logique hybride AL + ↓ + @ coïncident. L’intérêt théorique général des opérateurs rétrogrades est brièvement discuté.
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30Johannes Rudbeckius’s Conclusio Collegii LogiciStudia Neoaristotelica 14 (2): 189-208. 2017.Propono hic conversionem in linguam Anglicam conclusionis Collegii Logici, anno 1608–1609 semestri studiorum spatio hiberno a Johanne Rudbeckio Wittenbergæ habiti. Hic commentarius prooemium in conversionem est. Rudbeckius primus Suecus erat, qui librum didacticum de logica publicavit. Maiorem partem libri iam anno 1606 scripserat, cum Mathesis Professor Upsaliensis esset, sed Logica ex optimis et præstantissimis autoribus collecta & conscripta non ante annum 1625 edita sit. Cum Johanne Canuti L…Read more
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26Classical Negation and Game-Theoretical SemanticsNotre Dame Journal of Formal Logic 55 (4): 469-498. 2014.Typical applications of Hintikka’s game-theoretical semantics give rise to semantic attributes—truth, falsity—expressible in the $\Sigma^{1}_{1}$-fragment of second-order logic. Actually a much more general notion of semantic attribute is motivated by strategic considerations. When identifying such a generalization, the notion of classical negation plays a crucial role. We study two languages, $L_{1}$ and $L_{2}$, in both of which two negation signs are available: $\rightharpoondown $ and $\sim$…Read more
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22Sur les « opérateurs rétrogrades »Philosophia Scientiae 8 145-160. 2004.Une logique d’« opérateurs rétrogrades » (OR) est définie en utilisant des jeux sémantiques, joués sur des modèles à deux dimensions, l’une pour le temps, l’autre pour les scénarios épistémiques. On démontre que l’expressivité de OR est plus grande que celle de la logique de base des attitudes propositionnelles (AL). De plus, on établit que les pouvoirs expressifs de OR et la logique hybride AL + ↓ + @ coïncident. L’intérêt théorique général des opérateurs rétrogrades est brièvement discuté.
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22Johannes Rudbeckius’s View on the Nature of LogicStudia Neoaristotelica 15 (2): 135-215. 2018.Johannes Rudbeckius, one of Sweden’s most influential figures in theology, pedagogy, and church-state relations in the 17th century, published two books on logic: Logica ex optimis et præstantissimis autoribus collecta & conscripta and Controversiæ logices vel potius earum epitome. In this paper, I present and critically discuss Rudbeckius’s view on the nature of logic as it can be reconstructed from these two works. This requires, in particular, identifying the larger intellectual framework wit…Read more
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14Modal logic of time divisionIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 363-387. 1998.
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10On Modal Logics, IF Logic, and IF Modal LogicIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 481-501. 1998.
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9On IF Modal Logic and its Expressive PowerIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 475-498. 1998.
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7Decidability of IF Modal Logic of Perfect RecallIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 111-131. 1998.
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6Three Nordic Neo-Aristotelians and the First Doorkeeper of LogicStudia Neoaristotelica 19 (1): 3-106. 2022.I discuss the views on logic held by three early Nordic neo-Aristotelians — the Swedes Johannes Canuti Lenaeus (1573–1669) and Johannes Rudbeckius (1581–1646), and the Dane Caspar Bartholin (1585–1629). They all studied in Wittenberg (enrolled respectively in 1597, 1601, and 1604) and were exponents of protestant (Lutheran) scholasticism. The works I utilize are Janitores logici bini (1607) and Enchiridion logicum (1608) by Bartholin; Logica (1625) and Controversiae logices (1629) by Rudbeckius;…Read more
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6On Modal Logics, IF Logic, and IF Modal LogicIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 481-501. 1998.
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5Intentionala objekt: några logiska synpunkterNorsk Filosofisk Tidsskrift 48 (3-4): 304-313. 2013.
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3Modal logic of time divisionIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 363-387. 1998.
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3Decidability of IF Modal Logic of Perfect RecallIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 111-131. 1998.
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2On IF Modal Logic and its Expressive PowerIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 475-498. 1998.
Areas of Specialization
Logic and Philosophy of Logic |
Philosophy of Language |
Possible World Semantics |
Areas of Interest
Varieties of Modality, Misc |