The principle of sustainability contains two objectives of justice regarding the conservation and use of ecosystems and their services: (1) global justice between different people of the present generation ("intragenerational justice"); (2) justice between people of different generations ("intergenerational justice"). Three hypotheses about their relationship – independency, facilitation and rivalry – are held in the political and scientific sustainability discourse. Applying the method of qualitative content analysis to important political documents and the scientific literature, we reveal six determinants underlying the different hypotheses: quantity and quality of ecosystem services, population development, substitutability of ecosystem services, technological progress, institutions and political restrictions.