My dissertation argues that constructivism, far from a post-Enlightenment invention, originated and flourished at the margins of formal philosophy from the fifth-century BC onwards. Rhetorical texts, namely, regularly assume that the individual lacks ahistorical properties: that cognition and the very form of mind and/or soul are linguistic and so social epiphenomena. The dissertation comprises chapters on Gorgias, Isocrates, Cicero, Quintilian, and Hermogenes.