Rhetorical studies of Mozart have assumed a rationalist conception of language, ignoring the empiricist model that actually dominated the Enlightenment. The two models, comparable structurally to the stile antico and style galant, collide in Mozart's learned finales. A study of three finales, from the Mass in C minor, the Concerto in E♭, K.449, and Die Entführung aus dem Serail, shows how Mozart negotiated irreducible contradictions within Enlightenment thought by switching between the two models.