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7Lehrer's dynamic theory of knowledgeIn Olsson Erik (ed.), The Epistemology of Keith Lehrer, Kluwer Academic Publishers. pp. 219--242. 2003.
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57Degrees all the way down: Beliefs, non-beliefs and disbeliefsIn Franz Huber & Christoph Schmidt-Petri (eds.), Degrees of belief, Springer. pp. 301--339. 2009.This paper combines various structures representing degrees of belief, degrees of disbelief, and degrees of non-belief (degrees of expectations) into a unified whole. The representation uses relations of comparative necessity and possibility, as well as non-probabilistic functions assigning numerical values of necessity and possibility. We define all-encompassing necessity structures which have weak expectations (mere hypotheses, guesses, conjectures, etc.) occupying the lowest ranks and very st…Read more
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64Words in contexts: Fregean elucidationsLinguistics and Philosophy 23 (6): 621-643. 2000.The paper suggests a way of viewing the two Fregean principles of compositionality and contextuality as working together in the enterprise of interpretation. A third Fregean theme, that of elucidation (more precisely, the elucidation of primitive, undefinable terms of logic, mathematics and metamathematics) secures a place for some version of the context principle in Frege's later writings. When thinking about the functioning of elucidations, Frege acknowledges a principle of charitable interpre…Read more
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22Belief revisionIn Jonathan Eric Adler & Lance J. Rips (eds.), Reasoning: Studies of Human Inference and its Foundations, Cambridge University Press. pp. 514--534. 2008.This is a survey paper. Contents: 1 Introduction -- 2 The representation of belief -- 3 Kinds of belief change -- 4 Coherence constraints for belief revision -- 5 Different modes of belief change -- 6 Two strategies for characterizing rational changes of belief - 6.1 The postulates strategy - 6.2 The constructive strategy -- 7 An abstract view of the elements of belief change -- 8 Iterated changes of belief -- 9 Further developments - 9.1 Variants and extensions of belief revision - 9.2 Updates …Read more
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50Two Dogmas of Belief RevisionJournal of Philosophy 97 (9): 503. 2000.The paper attacks the widely held view that belief revision theories, as they have been studied in the past two decades, are founded on the Principle of Informational Economy. The principle comes in two versions. According to the first, an agent should, when accepting a new piece of information, aim at a minimal change of his previously held beliefs. If there are different ways to effect the belief change, then the agent should, according to he second version, give up those beliefs that are leas…Read more
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15Supplying Planks for Neurath's Boat: Can Economists Meet the Demands of the Dynamics of Scientific Theories?In Friedrich Stadler (ed.), Vienna Circle Institute Yearbook, Springer. pp. 11--225. 2004.According to Otto Neurath, the practice of science consists in a large undertaking of setting up and maintaining systems of statements: In unified science we try ... to create a consistent system of protocol statements and nonprotocol statements . When a new statement is presented to us we compare it with the system at our disposal and check whether the new statement is in contradiction with the system or not. If the new statement is in contradiction with the system, we can discard this statemen…Read more
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Von Rang und Namen. Philosophical Essays in Honour of Wolfgang Spohn (edited book) (edited book)Mentis. 2016.This collection includes twenty original philosophical essays in honour of Wolfgang Spohn. The contributions mirror the scope of Wolfgang Spohn’s work. They address topics from epistemology (e.g., the theory of ranking functions, belief revision, and the nature of knowledge and belief), philosophy of science (e.g., causation, induction, and laws of nature), the philosophy of language (e.g., the theory of meaning and the semantics of counterfactuals), and the philosophy of mind (e.g., intentional…Read more
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81Preservation and Postulation: Lessons from the New Debate on the Ramsey TestMind 126 (502). 2017.Richard Bradley has initiated a new debate, with Brian Hill and Jake Chandler as further participants, about the implications of a number of so-called triviality results surrounding the Ramsey test for conditionals. I comment on this debate and argue that ‘Inclusion’ and ‘Preservation’, which were originally introduced as postulates for the rational revision of factual beliefs, have little to recommend them in the first place when extended to languages containing conditionals. I question the phi…Read more
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Disagreement and misunderstanding across culturesIn Christian Kanzian & Edmund Runggaldier (eds.), Cultures: Conflict – Analysis – Dialogue, Proceedings of the 29th International Wittgenstein Symposium, Ontos. 2007.Communication problems between members of different cultures may be due to "genuine" disagreement or "mere" misunderstanding. I argue that there is anthropological evidence that efficient communication across different cultures and languages is feasible, since (i) the degrees of sophistication in thinking or talking are not fundamentally different (the case of "Chinese counterfactuals") and (ii) the basic logics used are not fundamentally different (the case of "Zande logic"). Disagreements and …Read more
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135Conditionals and theory change: Revisions, expansions, and additionsSynthese 81 (1): 91-113. 1989.This paper dwells upon formal models of changes of beliefs, or theories, which are expressed in languages containing a binary conditional connective. After defining the basic concept of a (non-trivial) belief revision model. I present a simple proof of Gärdenfors''s (1986) triviality theorem. I claim that on a proper understanding of this theorem we must give up the thesis that consistent revisions (additions) are to be equated with logical expansions. If negated or might conditionals are interp…Read more
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15Vom Fließen theoretischer Begriffe. Begriffliches Wissen und theoretischer WandelKant Studien 95 (1): 29-51. 2004.Ein theoretischer Begriff erhält seine Bedeutung aus einer Reihe von bedeutungskonstitutiven oder "analytischen" Sätzen der betreffenden Theorie. Die Bedeutungen der theoretischen Begriffe können sich ändern, wenn sich die Theorien ändern. Nach einer Diskussion von Kant und Frege schlage ich eine weitgehend quineanische Interpretation von Analytizität vor, ohne jedoch die Quine'sche Bedeutungsskepsis zu übernehmen. Ein Satz einer bestimmten Theorie in einer bestimmten Sprache wird analytisch gen…Read more
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85A New Psychologism in Logic? Reflections from the Point of View of Belief RevisionStudia Logica 88 (1): 113-136. 2008.This paper addresses the question whether the past couple of decades of formal research in belief revision offers evidence of a new psychologism in logic. In the first part I examine five potential arguments in favour of this thesis and find them all wanting. In the second part of the paper I argue that belief revision research has climbed up a hierarchy of models for the change of doxastic states that appear to be clearly normative at the bottom, but are more amenable to an empirical-descriptiv…Read more
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1'Severe Withdrawal (and Recovery)'(Reprinted from vol 27, pg 501, 1999, with corrections)Journal of Philosophical Logic 29 (1). 2000.
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61Reduction: Some criteria and criticisms of the structuralist conceptErkenntnis 27 (2). 1987.Inter-theoretical reduction has always been a major topic in the structuralist philosophy of science. This paper reviews criteria of adequacy which were put forward by Adams, Sneed, Stegmuller, Mayr, Pearce, Kamlah, and Mormann. The criteria are formalized in a simplified structuralist model, and the logical relations between them are investigated. It turns out that various parts of these criteria are incompatible.
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77Safe Contraction RevisitedIn Sven Ove Hansson (ed.), David Makinson on Classical Methods for Non-Classical Problems (Outstanding Contributions to Logic, Vol. 3), Springer. 2014.Modern belief revision theory is based to a large extent on partial meet contraction that was introduced in the seminal article by Carlos Alchourrón, Peter Gärdenfors, and David Makinson that appeared in 1985. In the same year, Alchourrón and Makinson published a significantly different approach to the same problem, called safe contraction. Since then, safe contraction has received much less attention than partial meet contraction. The present paper summarizes the current state of knowledge on s…Read more
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93Modellings for belief change: Prioritization and entrenchmentTheoria 58 (1): 21-57. 1992.We distinguish the set of explicit beliefs of a reasoner, his "belief base", from the beliefs that are merely implicit. Syntax-based belief change governed by the structure of the belief base and the ranking ("prioritization") of its elements is reconstructed with the help of an epistemic entrenchment relation in the style of Gärdenfors and Makinson. Though priorities are essentially different from entrenchments, distinguished relations of epistemic entrenchment may be obtained from prioritized …Read more
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2Understanding Fiction: Knowledge and Meaning in Literature (edited book)Mentis. 2012.The book addresses the questions how literature can convey knowledge and how literary meaning can arise in the face of the fact that fictional texts waive the usual claim to truth. Based on the interdisciplinary cooperation of literary scholars and analytic philosophers, the present anthology attempts a) to analyze the possibility and conditions of gaining knowledge through literature, and b) to apply, in a fruitful way, philosophical theories of meaning and interpretation to the constitution of…Read more
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41Das Ende vom Problem des methodischen Anfangs: Descartes' antiskeptisches ArgumentIn Gereon Wolters & Martin Carrier (eds.), Homo Sapiens Und Homo Faber, De Gruyter. 2005.Descartes' Meditations do not end up sceptical at all. In fact, the sixth meditation displays an intriguing epistemological optimism. Descartes affirms without reservation that knowledge of the external world is possible. The antisceptical argument at the end of the Meditations is often interpreted as a refutation of dream scepticism, with the conclusion that a person in the waking state can also determine that he or she is awake. We examine the logic of the argument in detail and find that thi…Read more
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20Zur Wissenschaftsphilosophie von Imre LakatosPhilosophia Naturalis 31 25-62. 1994.Dogmatic, naive and sophisticated falsificationism are construed as being distinguished by different views on the revisability of scientific theories. Then Lakatos's methodology of scientific research programs (SRP) is reinterpreted: The structure of an SRP is a target theory equipped with a priority structure for hypothetical revisions that accommodate idealizing assumptions. Idealizations pointing "backwards" capture predecessor theories, thus showing both their virtues and limitations. The co…Read more
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67Bounded Revision: Two-Dimensional Belief Change Between Conservative and Moderate RevisionJournal of Philosophical Logic 41 (1): 173-200. 2012.This paper presents the model of ‘bounded revision’ that is based on two-dimensional revision functions taking as arguments pairs consisting of an input sentence and a reference sentence. The key idea is that the input sentence is accepted as far as (and just a little further than) the reference sentence is ‘cotenable’ with it. Bounded revision satisfies the AGM axioms as well as the Same Beliefs Condition (SBC) saying that the set of beliefs accepted after the revision does not depend on the re…Read more
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313Two dogmas of belief revisionJournal of Philosophy 97 (9): 503-522. 2000.The paper attacks the almost universally held view that belief revison theories, as they have been studied in the literature of the past two decades, are founded on a Principle of Minimal Change, or Principle of Informational Economy. The principle comes in two versions. According to the first, an agent should, when accepting new information, aim at a posterior belief set that minimizes the items on which it disagrees with the prior belief set. If there are different ways to effect the belief ch…Read more
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12Supplying Planks For Neurath’s Boat: Can Economists Meet The Demands of The Dynamics of Scientific Theories?Vienna Circle Institute Yearbook 11 225-245. 2004.According to Otto Neurath, the practice of science consists in a large undertaking of setting up and maintaining systems of statements: In unified science we try... to create a consistent system of protocol statements and nonprotocol statements. When a new statement is presented to us we compare it with the system at our disposal and check whether the new statement is in contradiction with the system or not. If the new statement is in contradiction with the system, we can discard this statement …Read more
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15Belief and meaning: Essays at the interface (edited book)Deutsche Bibliothek der Wissenschaften. 2002.Theories of belief and meaning have long occupied philosophers. Typically, there is a correlation between the meaning of a sentence that is uttered and the content of the attitude that the speaker thereby conveys. This is also why a sentence can be used to specify content in an attribution of the attitude to the speaker. From the perspective of a theory of semantic content, there is a level of description where mental states and sentences can be said to share a content or meaning. But there is a…Read more
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12Possibility and Reality (edited book)Walter de Gruyter. 2003.Die Philosophie wurde von so unterschiedlichen Philosophen wie Wolff und Russell als Moglichkeitswissenschaft bezeichnet. Doch erwiesen sich die modalen Konzepte von Moglichkeit und Notwendigkeit als sperrig und vieldeutig, und ihr Verhaltnis zum Wirklichkeitsbegriff bleibt problematisch. Die vorliegende Sammlung beleuchtet die Metaphysik und Logik von Moglichkeit und Wirklichkeit aufs Neue und betrachtet sie aus unterschiedlichsten Perspektiven jenseits der Dichotomie von analytischer und konti…Read more
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17Drawing Inferences from ConditionalsIn Eva Ejerhed Sten Lindström (ed.), Logic, Action and Cognition: Essays in Philosophical Logic, Kluwer Academic Publishers. pp. 149-179. 1997.This paper compares three accounts of what can be inferred from a knowledge base that contains conditionals: Lehmann and Magidor’s Rational Entailment; Pearl’s System Z, later extended and refined in collaboration with Goldszmidt; and the present author’s Nonmonotonic conditional logic for belief revision. We show that although the ideas motivating these systems are strikingly different, they are formally equivalent. An explanation of the surprising parallel is offered in terms of the interpreta…Read more
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51Idealizations, intertheory explanations and conditionalsIn Erik J. Olsson & Sebastian Enqvist (eds.), Belief Revision Meets Philosophy of Science, Springer. 2011.Drawing inspiration from Lakatos’s philosophy of science, the paper presents a notion of intertheory explanation that is suitable to explain, from the point of view of a successor theory, its predecessor theory’s success (where it is successful) as well as the latter’s failure (where it fails) at the same time. A variation of the Ramsey-test is used, together with a standard AGM belief revision model, to give a semantics for open and counterfactual conditionals and ’because’-sentences featuring …Read more
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114Change, choice and inference: a study of belief revision and nonmonotonic reasoningOxford University Press. 2001.Change, Choice and Inference develops logical theories that are necessary both for the understanding of adaptable human reasoning and for the design of intelligent systems. The book shows that reasoning processes - the drawing on inferences and changing one's beliefs - can be viewed as belonging to the realm of practical reason by embedding logical theories into the broader context of the theory of rational choice. The book unifies lively and significant strands of research in logic, philosophy,…Read more
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11Vom Primat der praktischen Vernunft: Logische Regeln als Regeln rationaler WahlIn Georg Meggle (ed.), Perspectives in Analytical Philosophy, De Gruyter. pp. 1--138. 1997.
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132A Puzzle About Disputes and DisagreementsErkenntnis 80 (1). 2015.The paper addresses the situation of a dispute in which one speaker says ϕ and a second speaker says not-ϕ. Proceeding on an idealising distinction between "basic" and "interesting" claims that may be formulated in a given idiolectal language, I investigate how it might be sorted out whether the dispute reflects a genuine disagreement, or whether the speakers are only having a merely verbal dispute, due to their using different interesting concepts. I show that four individually plausible princi…Read more
Areas of Interest
Epistemology |
Logic and Philosophy of Logic |
Philosophy of Language |
Belief Revision |