ABSTRACT
This chapter introduces four different types of expertise: advisors, specialists, commentators, and artificial intelligence. It derives these from a typology where cognitive and practical considerations are applied to well-defined and ill-defined problems. The belief that experts can master well-defined problems through their technical competence, and through routine operations that are conducted outside the public view, has been shaken during the last decades. New issues emerge that need to be dealt with before they can be described as well-defined, and well-defined problems have turned out to be ill-defined as they became object of public controversy. This opens the space for the commentator, a type of expert who offers analysis, opinion and practical advice. Commentators make use of rhetorical tools and develop narratives.
