Citizen deliberation on technoscientific developments is regularly regarded as a hallmark of Danish democracy, embodied in particular by the Danish Board of Technology. Few empirically guided questions have been raised, however, as to how the Board's democratic projects actually work. Through a case study of the May 2003 Danish consensus conference on environmental economics as a policy tool, the article reflects on the politics of expert authority permeating practices of public participation. Adopting concepts from the sociology of scientific knowledge (SSK), the conference is seen as opening up the "black box" of environmental economics, forcing economists into attempted justifications of their shared normative and methodological commitments. The failure of environmental economists to reflect on their social value positions is suggested as key to understanding their less-than-successful defense in the citizen perspective. Further, consensus conferences are viewed alternatively as "expert dissent conferences," serving to disclose a multiplicity of expert commitments. From this perspective, some challenges for democratizing expertise through future exercises in public participation are suggested.