Kenneth Arrow, co-recipient of the 1972 Nobel Memorial Prize in Economic Sciences, passed away in February. This column outlines the ideas of one of the transcendent minds in the history of economics. The author, holder of a chair named in Arrow’s honour, notes that while his contributions were central in creating much of what constitutes modern quantitative social science, he was always profoundly aware of the limitations of the edifice, constantly seeking to challenge and broaden economic theory.