Since the publication of Our Common Future in 1987, scientists have struggled with the concept of sustainability and many definitions are now in existence. However, one can differentiate between a much smaller series of themes. Working from these definitions, we focus on six such themes. We will furthermore show that these themes are the battleground for two opposing worldviews within Western society which rule each other out. The first, the idealistic strand, operates in clear opposition to mainstream politics. Economic growth in this worldview cannot continue because in the end it will destroy nature and with it human society. It is therefore usually labelled as 'pessimistic'. This pessimism should however be viewed as a political tool in the search for the 'good society'. By contrast, the conformist strand adherents are contemporary 'optimists'. They do not envision a break with the past. The agenda here is that of political and economic continuity. Both sides in the debate claim the strategy of the other as impossible. The debate about sustainability should overcome this blockade to get back on course. © 2005 Taylor & Francis.