 A major problem in the epistemology of risk is how to deal with the limitations that characterize our knowledge of the behaviour of unique complex systems that are essential for estimates of risk, such as the climate system, ecosystems, the world economy, etc. Each of these systems contains so many components and potential interactions that important aspects of it are unpredictable. However, in spite of this uncertainty, reasonably reliable statements about many aspects of these systems can be made. Anthropogenic climate change is an example of this. Although many details are unknown, the general picture is clear, and there is no reasonable doubt about the existence of anthropogenic climate change, about its major causes and mechanisms, or the overall nature of the risks that it creates for our societies (Mayer et al. 2017; Lewandowsky et al. 2018). The epistemological status of such partial knowledge about complex systems, and the nature of the uncertainty involved, are still in need of further clarification (McKinney 1996, Shrader-Frechette 1997).