Why did Igor Stravinsky use repetition and subtle variation instead of traditional thematic development?

Igor Stravinsky rejected the Germanic tradition that viewed thematic development as the sole foundation for serious musical composition. Instead, he adopted a "sculptural" approach, prioritizing the "sound object" as the primary element of his work.1

Rather than relying on traditional thematic evolution, Stravinsky achieved large-scale musical structures cumulatively. He preferred to subject his material to a personal system of tests, experimenting with chord combinations, asymmetrical metrical patterns, and devices of prolongation and elision to break away from symmetrical phrasing. By treating sonorities as basic sound objects, he viewed rhythm as a cumulative process—an adding together of these objects into varied groups—rather than the varied subdivision of regular groups found in classical music.1

Consequently, his compositions often feature significant repetition combined with subtle variations in interior detailing. In his longer theatrical and sacred works, this technique creates an effect of ritual, where the music functions as a solemn reenactment rather than a developmental narrative.1