Navigating causal reasoning in sustainability science

Sustainability researchers aim to generate knowledge about causes of societal problems and possible solutions. Given the multidisciplinary nature of the field and the complexity of the problems, the causal reasoning that underlies these activities may vary significantly across studies and research approaches. Causal reasoning involves many assumptions, e.g. about what aspects of a system matter, what counts as evidence for a causal claim or what biases the data. These assumptions influence the emerging causal understandings, yet they are rarely made explicit. We clarify when and how causal reasoning manifests during a research process and how it is shaped by the goals of a study and the underlying idea of causation. Drawing on philosophy of science and recent discussions in the social and natural sciences, we identify four fundamental ideas and illustrate and compare them through examples. Awareness of these differences’ influence on causal reasoning helps better evaluate causes and solutions and identify synergies to strengthen causal claims on complex sustainability problems.