Abstract

In 1955 John Harsanyi proved a remarkable theorem that connects general good with the personal good of individuals. This chapter interprets Harsanyi’s theorem. It explains the meaning of its conclusion, the way it links together intrapersonal and interpersonal aggregation, and in particular the link it makes between the value of avoiding risk and the value of avoiding inequality between people. It explains how the theorem connects prioritarianism with risk avoidance and utilitarianism with risk neutrality. It sets out the theorem’s premises and assesses the various objections that have been made to them. Finally, it considers how far Harsanyi’s theorem gives support to utilitarianism.