Développement durable et principe de légitimité

The idea of sustainability idea reflects needs and absences: the unsustainable character of present patterns of development, the reference to absent beings (coming generations), legitimacy trouble touching environmental policies, but also the discovery that the sustainability idea cannot stand for an alternative legitimacy principle. After having identified the sources of weakness as lying in difficulties with the axioms of "common humanity" and 'equal power of access to social states' which are inherent in the "fair city" model, the paper shows that each alternative among existing principles runs into problems related to the ability to make promises for the future times. Sustainable development must therefore be sought in "legitimacy compromises".