This article establishes a dialogue between twenty-first-century music theory and historical modes of enquiry, adapting the new Formenlehre (Caplin, Hepokoski/Darcy) to serve a historically oriented hermeneutics. An analytical case study of the first movement of Haydn's Symphony No. 92 (1789) traces the changing functional meanings of the opening 'caesura prolongation phrase'. The substance of the exposition consists largely of things functionally 'before-the-beginning' and 'after-the-end', while the recapitulation follows a logic of suspense and surprise, keeping the listener continually guessing. The analysis calls into question Hepokoski and Darcy's restriction of the mode of signification of sonata-form movements to the narration of human action. The primary mode of signification of the recapitulation is indexical: it stands as the effect of a human cause. This account matches late eighteenth-century concepts of 'genius'.