As described in Chapter 5, there is considerable uncertainty when we set out to predict the future. Nature is complex, and we frequently do not anticipate outcomes-direct and indirect-of our actions. Still, we have no choice but to act on the best information we have to anticipate outcomes and to mitigate those we find to be undesirable. In an important sense that is what design is, and always has been, about. Designing for sustainability is extending the scope of the designer’s concern to include the environmental and human welfare implications of our design and the effects it can be expected to have in the future. In the end, we will assess design in terms of contributions made, in Ehrenfeld’s terms, to human flourishing.1 As this is written we are in the process of learning what that means regarding day-to-day practice and of adapting to new expectations in the marketplace. As noted in the first pages of this book, at the very heart of this adaptation is a value shift and a change in the underlying philosophy of design. Perhaps we are in a time where the old Epimethean philosophy is being replaced by an emerging Promethean ethos.