Objective and Cognitive Context

In what follows I consider the apparent contrast between two kinds of theories of context: a theory of objective context-exempliied in the works of Kaplan and Lewis-and a theory of subjective context-exempliied in the works of McCarthy and Giunchiglia. I consider then some diiculties for the objective theory. I don't give any formalization; instead I give some theoretical points about the problem. A possible result could be the abandon of the double indexing for a development a multi-context theory (I give an example of a case). However other results could be possible and a challenge is posed to solve problems using the best results from each tradition of research. 1 Two Concepts of Contexts Contexts are not things we nd in Nature; there are so many diierent ways of using the term \context" (in philosophy, linguistics, psychology, theory of communication, problem solving, cognitive science, artiicial intelligence) that it would be better to speak of a \family-resemblance" concept. Since Dummett we speak of the \context principle" in Frege and Wittgenstein; we speak of \context of utterance" in pragmatics; we speak of \context sensitive" grammars in linguistics , and we speak also of \linguistic context" and \non linguistic context". Studying the many attempts to have a better grasp of what kind of concept a context is, it is easy to nd a strong counterposition between an objective and a subjective view of context 1. Two paradigmatic positions representing these alternative views are the model theoretical tradition and the artiicial intelligence tradition. Both traditions give formal settings to treat contexts; here I will restrict myself to conceptual analysis. On one hand I will focus-for its clarity-on the original theory presented by David Kaplan, even if the model The main ideas of this paper have been discussed in a talk at Pittsburgh Center for the Philosophy of Science during 1998; I wish to thank Horacio Arll o Costa, Paolo Bouquet, Michael Green, Marcello Frixione and some unknown referees for their very useful comments 1 In giving this counterposition I strongly rely on 7], who speak of the contrast between \pragmatic" and \cognitive" contexts, and on 3], who speak of the contrast between metaphysical and cognitive context