In light of the 'Third Wave' debate on expertise (see Collins and Evans 2002; Collins and Evans 2007; Wynne 1992 Wynne , 2003 , a distinction can be made between a 'relational' versus a 'realistic' view on expertise. In this paper we will look at the experts and their expertise from a relational or social role perspective (Collins and Evans 2007, p. 2) . We treat the role of experts not as a given solid state, but as something in flux. This flux is the net result of interactions between the actions of individuals, and the attributing of trust and credibility by others (viz. Goffman 1959, pp. 15-16; Wynne 1992, p. 282; Huitema and Turnhout 2009, p. 579) , turning the experts into 'hybrid characters' (Daston and Sibum 2003) . A role in this understanding cannot be attributed solely to what the individual expert wants. Roles are contingent outcomes of these interactions, in which trust and credibility play a crucial part.