"I think, for me, in the times we are moving into now the concept or resilience is a much more useful idea than that of sustainability. Sustainability implies that we are trying to design a steady-state system with less inputs and less outputs than we have at the moment, which can carry on indefinitely. Whereas actually what we need to be designing for is the ability to withstand shock. But a lot of the literature about resilience talks about it meaning that a system can take shock, and then reform into its previous state. Whereas increasingly, the way people are starting to look at it, it's about seeing that shock as an opportunity to change."