- Metalogical properties of formal systems in their relation to realist and essentialist ontologies. - Problems in epistemic logic. - The different rule systems on which the production and understanding of language sequences are based. - The relation between linguistic and artistic meaning. - Philosophical problems in connection with developments in cognitive science and Artificial Intelligence (personal identity, mental causality,...) - Critical reflection on several oppositions characterizing Western thought since the Age of Enligthenment (fact-value, cognitive-affective, nature-nurture, ...). - Self-reference and indexicality.