Scientific consensus on sustainability: The case of the natural step

The Natural Step (TNS) is internationally promoted as the basis of a scient ific consensus on sustainability. TNS appears potentially consensual becaus e it argues from a position of summary trends that are scientifically infor med. However, comparison with other sustainability principles shows that th is appearance is unjustified. Firstly, this is because sustainability princ iples vary widely in their implications and purpose. Secondly, TNS is ambig uous in its approach to risk assessment and controversial in its implied pr oposal for zero growth in the physical parameters of the human economy, bio degradable material excepted. Two concepts from the sociology of science ar e used to account for international corporate and public uptake of TNS, des pite its ambiguity and highly precautionary message. These are the boundary object and anchoring devices. TNS illustrates how operationalization of su stainability theories unavoidably involves value judgements relating to the choice of features to be sustained, despite any scientific content that th ose theories may have. Copyright (C) 2000 John Wiley & Sons, Ltd and ERP En vironment.