Composition for Arnold Schoenberg is a comprehensible presentation of a musical idea (musikalische Gedanke); the totality of a piece represents the idea. For tonal works, he defines Gedanke as a process of resolving the "tonal relation" or "tonal problem." Contrary to the numerous tonal examples illustrating the notion of Gedanke, Schoenberg hardly expounds on the Gedanke principle for his atonal and twelve-tone repertoires. This study reevaluates Schoenberg's compositional philosophy and aesthetics including Gedanke, comprehensibility, Grundgestalt, and developing variation in light of his compositional practices in Begleitungsmusik zu einer Lichtspielszene, Op. 34. Although Schoenberg denies the existence of a tonal problem and hierarchy among pitches in twelve-tone compositions, the registral placement found in Op. 34 indicates certain functionality assigned to each pitch-class, producing a sense of "departure and return." The approach here elucidates the "idea" of Op. 34, in which the large-scale formal organization unfolds through contextually emphasized tonal relations. This study also explores Schoenberg's concept of the multi-dimensional presentation of a musical idea. Even though Schoenberg's discussion of musical coherence is usually limited to the immediate musical surface, I believe that he was also aware of an extended realization of foreground motives in the sense of Heinrich Schenker's "concealed motivic repetition." This analysis of Op. 34 demonstrates how the enlargement of a surface motive facilitates an understanding of the relation between the parts and the whole, which is perceived as the totality of Gedanke.