In Chapter 10, we return to one of the starting points of science and technology studies, namely that science and technology not only produce both opportunities and risks for society, but also change society and the environment. We thus ask what kind of knowledge would be useful for governance of change towards sustainability – or more precisely: for governance in and not of complexity, to draw on Arie Rip’s distinction. We take a brief detour on different theories of complexity and argue that the circular economy may fall into reductionist complexity. As an alternative, we argue that what is needed is an epistemology of complexity to navigate the multiple non-equivalent representations of the economy and its relationship with the environment, rather than a description of what complexity is. This approach develops a “quantitative story-telling” for governance in complexity. Quantitative story-telling combines STS/social research that identifies policy narratives and imaginaries with quantitative methods to explore their biophysical feasibility and economic viability. Rather than trying (in vain) to speak Truth to Power, this type of science aims to improve political and democratic dialogue by exploring and clarifying the implications of different policy options. This could be one strategy to possibly utilise the knowledge from the sciences mentioned in Chapter 9 as those studying Earth as a finite and limited system without necessarily falling into the narratives of Stop.