lundi 8 octobre 2007

Helge's update

La conférence de Helge Rückert sur les contextes intensionnels, initialement prévue le mercredi 10 octobre, est reportée au vendredi 12 octobre de 14h à 16h en salle 008 de la Maison de la Recherche.

Venez nombreux !

Intensional contexts ? A myth !
(Helge Rückert)

It seems to be not much more than a well known truism that there are intensional contexts, contexts in which the substitution of an expression with a co-extensional one might lead to a different truth-value of the whole sentence. Modal contexts, attributions of propositional attitudes and citations are supposed to be paradigmatic examples for such contexts.
However, in this talk I will claim that according to a more adequate logical analysis those contexts turn out to be extensional, too. First, I will argue that modal expressions like “necessary” and “possible” should rather be treated as quantifier-like expressions binding so-called subjunctive markers (instead of being operators). It is easy to show that according to such a treatment modal contexts turn out to be extensional. Then I will go on and apply those ideas to attributions of belief and knowledge and contexts of citation, too.
In the concluding remarks it is discussed what separates those contexts which are usually held to be intensional, from those contexts which are usually held to be extensional, although our language is extensional through and through.

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