I am interested in logic and natural language, quantification theory, and various applications of game-theoretical methods to the study of logic (game-theoretical semantics, dialogical games, etc.) In the last 25 years I have developed with several collaborators (initially with Jaakko Hintikka) a logical system called Independence-Friendly Logic (IF logic). I applied it to the study of various natural language phenomena, the expressibility of truth, foundations of  mathematics, but most recently I have been interested in the investigation of various notions of dependence and independence in logic. Most recently I focused on applications of IF logic to various notions of causality, both deterministic and probabilistic in Pearl-Woodward style. I have also published on Early Analytic philosophy (Frege, Russell, Ramsey).