Abstract
The legitimacy of technology as a whole, of individual fields of technology, and of concrete decisions on technology has become problematic. Traditional methods and elements for the legitimization of technological development and of the application of technology have been increasingly called into question since the 1980s. There are great expectations in participatory procedures to improving the legitimization of technology decisions. Those expectations, however, might not be justified. In the paper, the hypothesis is proposed that legitimacy can be brought about through participation only under conditions that require the fulfillment of a number of preconditions, which often cannot be regarded as fulfilled. The unavoidable separation between internal communication among the participants and external communication with the nonparticipants turns out to be the fundamental structural characteristic hindering naïve expectations of improving legitimacy by participation