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Deductive reasoning from uncertain conditionals
 British Journal of Psychology
, 2002
"... This paper begins with a review of the literature on plausible reasoning with deductive arguments containing a conditional premise. There is concurring evidence that people presented with valid conditional arguments such as Modus Ponens and Modus Tollens generally do not endorse the conclusion, but ..."
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This paper begins with a review of the literature on plausible reasoning with deductive arguments containing a conditional premise. There is concurring evidence that people presented with valid conditional arguments such as Modus Ponens and Modus Tollens generally do not endorse the conclusion, but rather find it uncertain, in case (i) the plausibility of the major conditional premise is debatable, (ii) the major conditional premise is formulated in frequentist or probabilistic terms, or (iii) an additional premise introduces uncertainty about the major conditional premise. This third situation gives rise to non monotonic effects by a mechanism that can be characterised as follows: the reasoner is invited to doubt the major conditional premise by doubting the satisfaction of a tacit condition which is necessary for the consequent to occur. Three experiments are presented. The first two aim to generalise the latter result using various types of conditionals and the last shows that performance in conditional reasoning is significantly affected by the representation of the task. This latter point is discussed along with various other issues: we propose a pragmatic account of how the tacit conditions mentioned earlier are treated in plausible reasoning; the relationship
DefLog: on the logical interpretation of prima facie justified assumptions
 Journal of Logic and Computation
"... Assumptions are often not considered to be definitely true, but only as prima facie justified. When an assumption is prima facie justified, there can for instance be a reason against it, by which the assumption is not actually justified. The assumption is then said to be defeated. This requires a re ..."
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Assumptions are often not considered to be definitely true, but only as prima facie justified. When an assumption is prima facie justified, there can for instance be a reason against it, by which the assumption is not actually justified. The assumption is then said to be defeated. This requires a revision of the standard conception of logical interpretation of sets of assumptions in terms of their models. Whereas in the models of a set of assumptions, all assumptions are taken to be true, an interpretation of prima facie justified assumptions must distinguish between the assumptions that are actually justified in the interpretation and those that are defeated. In the present paper, the logical interpretation of prima facie justified assumptions is investigated. The central notion is that of a dialectical interpretation of a set of assumptions. The basic idea is that a prima facie justified assumption is not actually justified, but defeated when its socalled dialectical negation is justified. The properties of dialectical interpretation are analysed by considering partial dialectical interpretations, or stages, and by establishing the notion of dialectical justification. The latter leads to a characterization of the existence and multiplicity of the dialectical interpretations of a set of assumptions. Since dialectical interpretations are a variant of stable semantics, the results are relevant for existing work on nonmonotonic logic and defeasible reasoning, on which the present work builds. Instead of focusing on defeasible rules or arguments, the present approach is sentencebased. A particular innovation is the use of a conditional that is prima facie justified (just like other assumptions) instead of an inconclusive conditional.
Belief Revision and Dialogue Management in Information Retrieval
, 1994
"... This report describes research to evaluate a theory of belief revision proposed by Galliers in the context of informationseeking interaction as modelled by Belkin, Brooks and Daniels and illustrated by userlibrarian dialogues. The work covered the detailed assessment and development, and computati ..."
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Cited by 12 (1 self)
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This report describes research to evaluate a theory of belief revision proposed by Galliers in the context of informationseeking interaction as modelled by Belkin, Brooks and Daniels and illustrated by userlibrarian dialogues. The work covered the detailed assessment and development, and computational implementation and testing, of both the belief revision theory and the information retrieval model. Some features of the belief theory presented problems, and the original `multiple expert' retrieval model had to be drastically modified to support rational dialogue management. But the experimental results showed that the characteristics of literatureseeking interaction could be successfully captured by the belief theory, exploiting important elements of the retrieval model. Thus though the system's knowledge and dialogue performance were very limited, it provides a useful base for further research. The report presents all aspects of the research in detail, with particular emphasis on the implementation of belief and intention revision, and the integration of revision with domain reasoning and dialogue interaction.
Penalty logic and its link with DempsterShafer theory
 In Proc. of the 10 th Conf. on Uncertainty in Artificial Intelligence
, 1994
"... Penalty logic, introduced by Pinkas [?], associates to each formula of a knowledge base the price to pay if this formula is violated. Penalties may be used as a criterion for selecting preferred consistent subsets in an inconsistent knowledge base, thus inducing a nonmonotonic inference relation. A ..."
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Cited by 12 (4 self)
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Penalty logic, introduced by Pinkas [?], associates to each formula of a knowledge base the price to pay if this formula is violated. Penalties may be used as a criterion for selecting preferred consistent subsets in an inconsistent knowledge base, thus inducing a nonmonotonic inference relation. A precise formalization and the main properties of penalty logic and of its associated nonmonotonic inference relation are given in the first part. We also show that penalty logic and DempsterShafer theory are related, especially in the infinitesimal case. 1 Introduction The problem of inconsistency handling appears when the available knowledge base  KB for short  (here a set of propositional formulas) is inconsistent. Most approaches come up with the inconsistency by selecting among the consistent subsets of KB some preferred subsets; the selection criterion generally makes use of uncertainty considerations, sometimes by using explicitly uncertainty measures (such as Wilson [?], Benfer...
Direct Dynamic Proofs For the RescherManor Consequence Relations: The Flat Case
 Journal of Applied NonClassical Logics
, 2000
"... It was shown in [6] that the at Rescher{Manor consequence relations the Free, Strong, Argued, CBased, and Weak consequence relationare all characterized by special applications of inconsistencyadaptive logics dened from the paraconsistent logic CLuN. As as result, these consequence relations ..."
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Cited by 10 (5 self)
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It was shown in [6] that the at Rescher{Manor consequence relations the Free, Strong, Argued, CBased, and Weak consequence relationare all characterized by special applications of inconsistencyadaptive logics dened from the paraconsistent logic CLuN. As as result, these consequence relations are provided with a dynamic proof theory. In the present paper we show that the detour via an inconsistencyadaptive logic is not necessary. We present a direct dynamic proof theory, formulated in the language of Classical Logic, and prove its adequacy. 1 Aim of this Paper Rescher{Manor consequence relations constitute an approach to handling inconsistency. The underlying idea is that inconsistent sets of sentences are divided into maximal consistent subsetshenceforth MCSand that what `follows ' from the inconsistent set is dened in terms of the classical consequences of the MCS or of a selection of themClassical Logic will henceforth be abbreviated as CL. Such consequence relati...
Making Counterfactual Assumptions
 Journal of Semantics
, 2005
"... This paper provides an update semantics for counterfactual conditionals. It does so by giving a dynamic twist to the ‘Premise Semantics ’ for counterfactuals developed in Veltman (1976) and Kratzer (1981). It also offers an alternative solution to the problems with naive Premise Semantics discussed ..."
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This paper provides an update semantics for counterfactual conditionals. It does so by giving a dynamic twist to the ‘Premise Semantics ’ for counterfactuals developed in Veltman (1976) and Kratzer (1981). It also offers an alternative solution to the problems with naive Premise Semantics discussed by Angelika Kratzer in ‘Lumps of Thought ’ (Kratzer, 1989). Such an alternative is called for given the triviality results presented in Kanazawa et al. (2005, this issue). 1
The cognitive structure of surprise: looking for basic principles
 International Review of Philosophy
, 2007
"... We develop a conceptual and formal clarification of the notion of surprise as a beliefbased phenomenon by exploring a rich typology. Each kind of surprise is associated with a particular phase of the cognitive processing and involves particular kinds of epistemic representations (representations an ..."
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Cited by 9 (4 self)
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We develop a conceptual and formal clarification of the notion of surprise as a beliefbased phenomenon by exploring a rich typology. Each kind of surprise is associated with a particular phase of the cognitive processing and involves particular kinds of epistemic representations (representations and expectations under scrutiny, implicit beliefs, presuppositions). We define two main kinds of surprise: mismatchbased surprise and astonishment. In the central part of the paper we suggest how a formal model of surprise can be integrated with a formal model of belief change. We investigate the role of surprise in triggering the process of belief reconsideration. There are a number of models of surprise developed in psychology of emotion. We provide several comparisons of our approach with those models.
Some Adaptive Logics for Diagnosis.
 Logic and Logical Philosophy
"... A logic of diagnosis proceeds in terms of a set of data and one or more (prioritized) sets of expectancies. In this paper we generalize the logics of diagnosis from [26] and present some alternatives. The former operate on the premises and expectancies themselves, the latter on their consequence ..."
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Cited by 5 (3 self)
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A logic of diagnosis proceeds in terms of a set of data and one or more (prioritized) sets of expectancies. In this paper we generalize the logics of diagnosis from [26] and present some alternatives. The former operate on the premises and expectancies themselves, the latter on their consequences.
Defeasible Logics
, 1998
"... Contents 0.1 Introduction : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1 0.2 Pearl's system Z : : : : : : : : : : : : : : : : : : : : : : : : : : : : 4 0.2.1 Deriving a natural ordering of defaults : : : : : : : : : : : : : 5 0.2.2 System Z + : resolving remaining ambiguities by exp ..."
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Cited by 5 (2 self)
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Contents 0.1 Introduction : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1 0.2 Pearl's system Z : : : : : : : : : : : : : : : : : : : : : : : : : : : : 4 0.2.1 Deriving a natural ordering of defaults : : : : : : : : : : : : : 5 0.2.2 System Z + : resolving remaining ambiguities by explicit means 7 0.3 Conditional entailment : : : : : : : : : : : : : : : : : : : : : : : : : 8 0.4 The argumentbased system of Simari and Loui : : : : : : : : : : : : 11 0.5 Brewka's preferred subtheories : : : : : : : : : : : : : : : : : : : : 16 0.6 Ordered logic and basic defeasible logic : : : : : : : : : : : : : : : : 19 0.6.1 Implicit version of Nute's basic defeasible logic : : : : : : : : 20 0.6.2 Ordered logic : : : : : : : : : : : : : : : : : : : : : : : : : 24 0.6.3 Explicit version of Nute's basic defeasible lo