In this essay I recover the juridical applications of `interest' in Roman law, and examine how their initial relationship to financial practices shifted, for a theoretical appreciation of interest-related subjectivity. Drawing on Hegel's discussion of Roman law, I explore the retrospective narrative of subjectivity constructed by the adjudication of interests before the term `interest' came to apply to money. Examining Albert Hirschman's argument that rationality of interest derives from its origins as a euphemism for usury, I describe how the verbal (...) change reflects the incursion of money into legal terrain that previously excluded it, representing a moment of categorical erosion within the law. I argue that monetary inflation is a critical context for interpreting the effects of this categorical erosion on interest-related subjectivity. Inflation replaces the retrospective narrative of identity with one that is future-oriented and is no longer determined at any single site of adjudication, and therefore remains contested. (shrink)