Widely regarded as a masterpiece of the twentieth-century ute repertoire, Paul Hindemith's Flute Sonata (1936) has received surprisingly little scholarly attention. While most sources agree that the first movement of the piece is in sonata form, interpretations of the second movement diverge, with some scholars emphasizing the movement's binary structure and others identifying sonata principles at work. In this paper, I argue that the second movement is in dialogue with what Hepokoski and Darcy (2006) call a Type 2 sonata. My analysis draws inspiration from Sonata Theory (2006), William Caplin's theory of formal functions (1998), David Neumeyer's work on Hindemith (1986), and the first volume of Hindemith's Craft of Musical Composition (1942). Whereas Neumeyer has downplayed the importance of the concept of harmonic fluctuation in Hindemith's works, I argue that it plays a fundamental role in cadential attainment and, therefore, the movement's hermeneutic implications.