NEW Making the right exceptions (with Harald Bastiaanse) [pdf]
Abstract : This paper provides a principled answer to the question of how to deal with conflicting default rules. It does so in two ways: semantically within a circumscriptive theory, and syntactically by supplying an algorithm for inheritance networks. Arguments that can be expressed in both frameworks are valid on the circumscriptive account if and only if the inheritance algorithm has a positive outcome.

Theme: Update semantics

The central paper under this heading presents the framework of update semantics, explains what kind of semantic phenomena can be analysed in this framework, and gives a detailed analysis of one such phenomenon: default reasoning.

It can be read online at the site of the  Philosopher's Annual .

An Update on Might [pdf] was written with Jaap van der Does and Willem Groeneveld. It presents a Gentzen- style proofsystem for the might-operator introduced in the paper mentioned above.

The next paper gives a dynamic twist to the 'premise' semantics for counterfactuals developed by Angelika Kratzer and myself in the late seventies.

  • Making counterfactual assumptions [pdf]
Jeroen Groenendijk, Martin Stokhof and I spent quite some time integrating Dynamic Predicate Logic in the framework of update semantics. The main result was the first of the next two papers which was published in The Handbook of Contemporary Semantics. The second paper is a short version of the first.
  • Coreference and Modality [pdf]
  • This Might Be It [pdf]
The next two papers are less formal and extend the theory of Coreference and Modality by supplying an analysis of anaphoric definite descriptions and other anaphoric terms like "one...the other". (As in: "Both papers cover the same ground, but one is written in English, and the other in French").
  • Coreference and Contextually Restricted Quantification [pdf]
  • Changez le Contexte! [pdf]
If you want to know why anaphoric expressions behave differently in multi-speaker discourse than in one-speaker discourse, read:
  • Coreference and Modality in Multi-Speaker Discourse [pdf]

Theme: Logic and cognition

Een zogenaamde denkfout [pdf] is written in Dutch. This is the English abstract:
Psychological experiments have repeatedly shown that in judging the likelihood of uncertain events people do not follow the principles of probability theory. A notorious example is given by the so-called conjunction fallacy. In this paper I argue that this fallacy is not really a fallacy when it is analysed in the light of a dynamic theory of default reasoning. The question that immediately rises is whether the fact that this theory conforms better to the way people actually think provides a reason to prefer it to probability theory.

Het verschil tussen vaag en niet precies [pdf] was my inaugural lecture. In English that would be "The difference between vague en not precise". It deals with the following topic:
Modern logic is anti-psychologistic: to determine wether a given conclusion is correct one does not have to look into the head of the person who draws it; logical laws are not laws of thought. However, this does not mean that one can do logic without taking notice of human cogntion. Our language is so intertwined with our cognitive abilities that it is impossible to understand the meaning -- and with this the logical properties -- of a considerable number of expressions without taking the cognitive circumstances in which they are used into account. This thesis is illustrated in a discussion of the logical behaviour of vague words like `big' and `many'.

Theme: Interpretability Logic

In interpretability logic the logical properties of the notion of interpretability are studied in much the same way as the logical properties of the notion of provability are studied in provability logic. The first paper mentioned below contains a completeness proof for the system ILW, a rather bewildering axiom system belonging to the family of interpretability logics. It can best be read as a sequel to the second paper, in which the basic system IL and the extensions ILM and ILP, which cover the interpretability logic of Peano Arithmetic and NBG set theory, are studied. Both papers were written with Dick de Jongh.
  • The Modal Completeness of ILW [pdf]
  • Provability logics for relative interpretabilty [pdf]

The bibliographical data for most of these papers are here.

In preparation

  • Or else, what? Imperatives at the semantics/pragmatics borderline.
  • Gradable adjectives and subjective experience (with Inés Crespo)

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