In the sustainability discourse we find much disagreement about the idea of sustainability resulting in the unsatisfactory situation that this idea is limited by arbitrariness and therefore looses its action guiding power. Examining various strategies to solve this challenge we argue for a meta-perspective. In the central part of this paper we describe a formal framework for conceptions of sustainability consisting of fundamental and practical modules. Subsequently, we critically compare this framework with alternative meta-approaches, in particular with the ‘Framework for Strategic Sustainable Development’. We conclude that the problem of arbitrariness is encountered on three different levels; in the designation of the subject field of the sustainability debate, in the characterisation of sustainability science and indirectly in providing a basis to assess policies. This underlines the framework's usefulness of structuring the discourse on sustainability. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.