Should decisions be based on knowledge, defined—as Plato proposed—as true and justified beliefs? In a multicultural society there are frequently different and diverging views about what we know. Our choices are influenced by the alternatives we see, how they are described, and how we suppose that their consequences will affect us and our descendants. If we want to be able to predict preferences, we need to understand the importance of how the problems are presented and how our minds work.

The idea that the rational individual maximizes his or her expected utility when making a decision—derived from Frank Ramsey’s essay ‘Truth and probability’, published in 1931—is an important point of departure in this collection of essays. It comprises case studies of difficult decision-making when faced with challenges, such as nuclear strategy, the climate crisis and care of extremely preterm-born children, as well as perspectives on philosophical issues raised by making rational decisions.