Hun Chung argues for a theory of distributive justice – ‘prospect utilitarianism’ – that overcomes two central problems purportedly faced by sufficientarianism: giving implausible answers in ‘lifeboat cases’, where we can save the lives of some but not all of a group, and failing to respect the axiom of continuity. Chung claims that prospect utilitarianism overcomes these problems, and receives empirical support from work in economics on prospect theory. This article responds to Chung's criticisms of sufficientarianism, showing that they are (...) misplaced. It then shows that prospect utilitarianism faces independent problems, since it too requires a threshold, which Chung bases on the idea of ‘adequate functioning’. The article shows that there are problems with this as a threshold, and that it is not empirically supported by prospect theory. (shrink)