I mainly work in the philosophy of mind and language, with occasional side trips into epistemology and action theory. My interests include the theory of meaning and content (both foundational and formal semantics), the normativity of meaning, belief, and reasons, and the philosophy of perception. I am also a bit of a Davidson scholar.

An expanded version of my M.A. thesis was published as Donald Davidson zur Einführung in 1993 (Hamburg, Junius Verlag). Donald Davidson: A Short Introduction, an updated and expanded English version of the German original, came out with Oxford University Press in 2011. I have a number of papers on Davidsonian themes, with a focus on issues in foundational semantics.

My dissertation Sprache und Regeln. Zur Normativität von Bedeutung (Berlin, Akademie Verlag 1999) presents and assesses the contemporary debate concerning semantic normativity. It defends the conclusion that meaning is not intrinsically normative, not essentially determined by norms, rules or conventions. The positions discussed include those of Dummett, Davidson, Kripke, McDowell, and Putnam as well as more or less orthodox Wittgensteinian positions. Often in cooperation with Peter Pagin and Åsa Wikforss, I have expanded and complemented the arguments presented in the dissertation in later articles. Åsa and I have also challenged the alleged normativity of mental content as well as that of belief, reasons, and rationality.

I am very interested in the theory of perception, especially as an area in which epistemology and the theory of content intersect. In a series of articles, I have developed and defended a position that I call “phenomenal intentionalism”. It construes visual perceptual experiences as a (peculiar) kind of belief with a rather particular form of content: looks-contents.

Together with Peter Pagin, I am also doing some work in formal semantics. We are developing a semantic framework we call “switcher semantics”. A monograph — working title: Switcher Semantics. A Semantic Defense of the Classical Proposition — is under contract with OUP. Switcher semantics is a generalized version of semantics working with more than one semantic evaluation function. Its key idea is that certain operators, such as intensional operators, function as “evaluation switchers”. Applying this idea to proper names and modal operators, we have suggested a semantics allowing names to have descriptive contents. We have extended switcher semantics to empty names, and also to general terms in a way that accounts for the name-like behavior of natural kind terms while allowing them to have descriptive contents. I have suggested that phenomenal ‘looks’ is best construed as a switcher, too, and Peter has been working on belief-contexts, temporal operators, and, with Dag Westerståhl, quotation.