Barriers to rational decision-making in environmental planning

Comparison of radically different solutions to environmental problems is often demanding in terms of knowledge-based clarification of decision criteria, as the options' consequences tend to vary along many variables. The idea of 'optimal' solutions is often difficult to apply in a meaningful way in such situations. The rationality of decisions must rather be addressed through analyses of the processes that preceded them. Ideas of rational discourse have been developed that are adapted to this approach. The perspectives of Foucault and Habermas are applied in an analysis of a case of wastewater management in a Norwegian municipality. The paper addresses the importance of trust and knowledge to rational discourse, as well as the dependence of these on power embedded in inert discursive structures. It is argued that early in the planning process, explicit debate among all parties involved on basic value premises and ensuing decision criteria is essential in order to prevent the public debate from being distorted by existent tacit discursive structures. (c) 2006 Elsevier Ltd. All rights reserved.