The Department of Theoretical Philosophy at Groningen extends its research over logic, epistemology, philosophy of science, philosophy of mind, metaphysics, and the theory of argumentation. The department is home to Jan-Willem Romeijn and — until recently — to Igor Douven, both of whom are world leading researchers in their areas. Romeijn’s work lies at the intersection of philosophical, statistical, and psychological issues. Consequently, his papers frequently appear in scientific journals. His strengths are in the epistemology of learning, and group consensus. Though no longer in Groningen, Douven has a long track record of collaborations with researchers at the other nodes, and will be visiting the network’s activities. Douven is one of the most prolific researchers worldwide in formal epistemology, with particular expertise in the epistemology of conditionals and their role in belief revision. He is also one of the pioneers in collaborating with psychologists for testing epistemic hypotheses.