Samuel Richardson’s final novel, The History of Sir Charles Grandison, incorporates the foundations of a sensibility that we might call “psychological fiction” found in such novels as Madame de Lafayette’s La Princesse de Clèves. Grandison depicts characters who revise, comment on, correct, and re-edit what they think they know about love, and Harriet Byron’s anti-romantic worldview mirrors that of a narrator of psychological fiction. Knowledge deepens quite slowly in Grandison, often moving one step forward and two steps back. Rather than just moral instruction, Richardson explores through Grandison a finely nuanced dissection of sentiment that incorporates and comments on the work of the French moralistes. This article compares the epistemology of love in Grandison to that found in La Princesse de Clèves, which Richardson cites and has his characters discuss in the seventh volume of his final novel.