The beliefs of a conspiracy theorist, terrorist, anti-institutional extremist or fundamentalist are all paradigm examples of extreme beliefs. However, it is far from clear what extreme beliefs are. What makes them problematic? And who decides? 
In this lecture, Naomi Kloosterboer and Nora Kindermann discuss the challenges of defining extreme beliefs, of understanding and explaining extreme beliefs in research contexts and of engaging with extreme believers in private and public circumstances.