This study presents a detailed analytical examination of formal organization in Anton Bruckner’s early instrumental slow movements: from the String Quartet, WAB 111, to the Third Symphony, WAB 103. It proposes an analytical methodology and conception of the formative process of musical works that seeks to 1) reappraise the development and idiosyncrasies of his slow movements’ form, and 2) turn the textual multiplicity often associated with Bruckner’s large-scale works (a scholarly issue often referred to as the “Bruckner Problem”) into a Bruckner Potential. In addressing traditional and innovative formal aspects of Bruckner’s music, critics have tended to overemphasize one side or the other, consequentially portraying his handling of form as either whimsical or excessively schematic. By way of a reconstruction of Bruckner’s early experiments with slow-movement form (1862–1873), this study argues that influential lines of criticism in the reception history of Bruckner’s large-scale forms find little substantiation in the acoustical surface of Bruckner’s music and its dialogic engagement with mid- and late-19th-century generic expectations. Because the textual multiplicity often associated with Bruckner’s works does not sit comfortably with traditional notions of authenticity and authorship, Bruckner scholarship has operated under aesthetic premises that fail to acknowledge textual multiplicity as a basic trait of his oeuvre. The present study circumvents this shortcoming by conceiving formal-expressive meaning in Bruckner’s symphonies as growing out of a dual-dimensional dialogue comprising 1) an outward dialogue, characterized by the interplay between a given version of a Bruckner symphony and its implied genre (in this case, sonata form); and 2) an inward dialogue, characterized by the interplay among the various individualized realizations of a single Bruckner symphony. The analytical method is exemplified through a detailed consideration of each of the surviving realizations of the slow movement of Bruckner’s Third Symphony, WAB 103.