Assessed from the standpoint of its omnipresence in Western societies or global politics, sustainable development has been a success. When looked at differently, however, it has rather been a failure. It is far from evident that justice towards future generations and the condition of nature have been improved. The moral challenge posed by Our Common Future 30 years ago is grand indeed, and combining intra- and inter-generational justice with a new relationship to nature—the threefold core of sustainability ethics—is quite a task. Changing mindsets might be the core of sustainability transformations. This chapter argues that the most intimate part of the mindset that must be changed to achieve a more fruitful understanding of sustainable development is our view of ourselves and the world. Until now, most of us see ourselves as separate beings, as individuals that relate to an external world. And this perspective is typically reinforced by the social sciences. But understanding humans (and other things) as interbeings, instead of separate entities, creates a different basis to appreciate the core of sustainability.