What the Demands of Sustainability Can(not) Be

Since the goal of “sustainable development” has gained authority (notably since the 1987 Brundtland Report), there have been attempts to characterize what, at core, is the intended constraint on present choice. Many think that it is about privileging development trajectories whereby each successive generation fares at least as well as the previous generation. We first prove that such a constraint is, however, incompatible with minimal consistency requirements. We subsequently explore how to escape this “impossibility” result. The most promising possibilities, we claim, amount to very different proposals regarding the scope and moral significance of the demands of sustainability.