Abstract

The twin concepts of ecological sustainability and ecologically sustainable development have been in circulation in international circles for about three decades. In South Africa these concepts have become cornerstones of both our new Constitution and our National Environmental Management Policy. And yet, there is still a highly intensive and wide ranging debate going on in international as well as national contexts in which both the meaning and implementation of these concepts are contested from different angles. In this article the reasons for this slate of affairs are explored from an ethical perspective, and a number of proposals are made on a philosophical and policy level to respond to the contested nature of these concepts. In an overview of the historical development of the concepts of ecological sustainability and ecologically sustainable development it is shown that they have emerged from different, and to some extent mutually exclusive, contexts. The paper then proceeds 10 a systematic discussion of a number of "fault lines~ within these concepts, in which the focus falls on certain internal tensions that make their interpretation very difficult, if not highly controversial. These tensions are associated with different ethical and ideological positions that can be assumed with regards to questions such as the following: 1. What is so valuable that it can and should be sustainable? 2. With a view to whom or what is the sustainability of this valuable something pursued? 3. How is sustain ability pursued? 4. What are the criteria for sustainabililY? - so that the question whether and when we have reached a state of sustainability can be answered. On the basis of an overview of these "fault lines" it becomes possible to distinguish between different conceptions and different models of ecological sustainabifity and ecologically sustainable development. The value of this taxonomy lies in the clarification that it brings to the muddy waters of ideological posturing about the meaning and implementation of the concepts of ecological sustainability and ecologically sustainable development