The intersecting-spheres depiction of sustainable development, where sustainability lies at the intersection of all three spheres (source: Johann Dréo, Wikimedia Commons) 

Context in source publication

Context 1

... the Brundtland definition is implicitly a statement of 'weak sustainability': that man-made capital be allowed to substitute for natural capital as the latter is depleted, based on the assumption that such man-made replacements will be found. The weak sustainability approach is often depicted as a trade off between the three (or four) pillars (Figure 1), indicating that the goal is balance. In contrast, the 'strong sustainability' approach is commonly represented as having non-negotiable limits set by the environment taking priority over those of society, which in turn take priority over those of the economy ( Figure 2). ...