This article is an analytical history of Paul Samuelson's writings on the theory of public goods and the role of government. We examine Samuelson's scholarly work from “The Pure Theory of Public Expenditure” (1954) to “Pure Theory of Public Expenditure and Taxation” (1969). We also briefly consider his treatment of public expenditure in Economics: An Introductory Analysis over the same period. We find that from the beginning of his career to the end of the 1960s Samuelson moved from optimism that a new age of scientific progress in economics was imminent to a view so pessimistic that he described it as nihilistic. This suggests that Samuelson's project of mathematizing and formalizing economic theory was a scientific failure.