Introduction: The first movement of Mozart’s Symphony No. 40 in G minor, K. 550, is frequently described as agitated, tragic, or restless. Although intuitively persuasive, such characterizations remain analytically limited unless they can be related to specific structural features of the score. This study therefore investigates how the movement supports an interpretation of structural anxiety through metric and hypermetric ambiguity, tonal and chromatic instability, motivic recurrence, formal function, and the temporal separation of cadential arrival from formal closure. Structural anxiety is not understood as a psychological state empirically experienced by every listener. Rather, it is defined more narrowly as the persistence and displacement of instability across different musical levels, whereby the stabilization of one parameter may coincide with renewed tension in another. This definition distinguishes the proposed concept from the conventional tensions inherent in sonata form and ensures that affective interpretation remains grounded in score-based evidence.
Methods: The research adopts a qualitative, theoretical, and analytical approach. Its primary source is the 1880 Breitkopf & Härtel complete score published in Mozarts Werke, Series VIII, available through IMSLP. The movement is divided into three main formal sections: exposition (mm. 1–100), development (mm. 101–164), and recapitulation (mm. 165–299). Their internal divisions are examined through Caplin’s theory of formal functions and Hepokoski and Darcy’s sonata-theoretical framework. The analysis distinguishes between bar-level meter and hypermeter, traces the opening motive and accompaniment pattern across the formal sections, examines tonal movement and significant chromatic intensification, and differentiates thematic boundaries, cadential goals, postcadential reinforcement, and closing functions. Analytical claims are assessed in relation to their precise locations in the score, their formal roles, and their implications for tonal and cadential expectations. The two transmitted orchestral versions, with and without clarinets, share the formal and metric features examined in this study. Differences in orchestral color are therefore acknowledged but do not affect the central analytical segmentation.
Findings: The opening establishes the movement’s central mechanism of structural anxiety. The viola accompaniment begins before the upper-string theme has fully taken shape, creating a discrepancy between the notated beginning and the perceptual emergence of the thematic idea. In mm. 1–20, the relative metrical weight of odd- and even-numbered bars permits more than one plausible hypermetric interpretation, as discussed by Lerdahl and Jackendoff and further developed by Dodson. The repetition of thematic material clarifies the musical idea without dispelling the underlying rhythmic instability. The transition in mm. 21–43 transforms this local ambiguity into directed formal and tonal pressure: intensification, modulation, and orchestral expansion propel the music toward the secondary key rather than merely connecting two self-contained thematic areas.
The secondary zone in B-flat major provides a genuine contrast but does not produce complete release. Its parallel phrases in mm. 44–51 and 52–66 culminate in a strong perfect authentic cadence in m. 66, which constitutes a convincing candidate for the essential expositional closure (EEC). This cadential arrival must nevertheless be distinguished from the beginning of the closing function. Measures 67–71 reinforce the cadence, whereas the P-based closing material begins in m. 72. The exposition therefore achieves tonal closure; the analytical issue is not a failure of cadential closure but the temporal separation of the EEC, postcadential reinforcement, and the onset of the closing section (C). The recurrence of primary-theme material within the closing section preserves earlier rhythmic and motivic energy even after the secondary key has been established.
The development intensifies this process by detaching recognizable material from stable tonal and formal contexts. Fragmentation, sequential repetition, modulation, and chromatic voice leading render familiarity itself unstable: the listener recognizes the material but cannot readily assign it a stable formal or tonal position. The recapitulation at m. 165 restores G minor while simultaneously reintroducing the opening accompaniment and thematic conditions that generated the initial tension. The tonal return thus resolves the large-scale tonal opposition established in the exposition without eliminating the movement’s characteristic instability. In the recapitulation, the secondary material is reinterpreted within the tonic domain, while the final closing section (mm. 261–299) establishes an unequivocal ending through reiteration, accentual emphasis, and decisive cadential articulation. The ending contains and brings closure to the accumulated musical energy rather than simply eliminating it.
Conclusion: The movement’s sense of unrest cannot be reduced to the minor mode, a single chromatic event, or a breakdown of Classical formal conventions. Rather, it emerges from a coordinated structural design in which instability shifts among hypermeter, tonal direction, motivic identity, cadential processes, and formal functions. Sonata form is therefore not merely a framework within which anxiety is expressed; its norm-governed processes generate, redistribute, intensify, and ultimately contain that anxiety. The concept of structural anxiety provides a theoretically grounded link between technical analysis and affective interpretation by requiring expressive claims to be supported by formal and tonal evidence. The study is limited to score-based analysis and does not claim that all listeners experience the movement in the same way. Further comparative research involving recordings, tempo, articulation, and empirical listening could investigate the extent to which different performances amplify or attenuate the structural relationships identified here.