This climactic movement is the only one in which contemplation is subordinated to the depiction of events in a definite sequence. The principal musical consequence is that the formal structure of the music acquires something of the teleological quality that we associate with the sonata principle in the Austro-German tradition. But Messiaen's own description of the form – ‘variations of the first theme, separated by developments of the second’ – makes it clear that his conception falls short of the dialectical interplay of themes and tonalities that post-Beethovenian sonata form frequently embodies. Nonetheless, the very idea of ‘development’ alerts us to something that distinguishes the treatment of themes in ‘Fouillis d'arcs-en-ciel …’ from, for example, the linkage through complementary aspects of plainsong between the melodic materials at ii/B:1–3 and D:1ff. in ‘Vocalise …’ (see pp. 29–31).

Developments

The comparison with the second movement is particularly germane because, as Messiaen makes clear, much of its material reappears here.