In Taruskin's marvelous history he links Messiaen with Scriabin as the last of what he describes as "maximalist transcendentalists". These composers (and some other less-known ones) were driven by a spiritual vision within which they subsumed a host of disparate influences. Both Ken and I have mentioned some of these, which include birdsong, Hindu and Greek rhythmic patterns and some medieval structural procedures.
What distinguishes Messiaen from his spiritualist forbears and indeed from his contemporaries and students is his quest for theological truth in his music. Part of this quest involves the use of rigorous compositional procedures, which was the source of his appeal to a whole generation of young composers, such as Boulez and Stockhausen, immediately after the Second World War. Ken has talked about these procedures, but as they are so interesting, I want to revisit them.
One remarkable aspect is that Messiaen takes the same approach to both pitch and rhythm: he sought both symmetry and invariance. How do you do that? Using Messiaen's unique terminology, by means of "non-retrogradable rhythms" and "modes of limited transposition". Both of these techniques lead to a kind of stasis. As you might recall from your counterpoint classes (whaddayamean you never studied counterpoint?), if you play a melody backwards, this is its "retrograde" form. Another word for it is "cancrizans". Follow the link for a full explanation. You can present both the pitches and rhythms backward or forward. This is an old technique and a particularly famous example is by Guillaume de Machaut (c. 1300 - 1377). This is a rondeau in three parts titled "Ma fin est mon commencement" ("My beginning is my end") and the music exactly reproduces the text! The beginning of the triplum:
is the same as the end of the cantus, but reversed:
Notice that both the notes and the rhythms are reversed. This has been used by quite a number of composers, including myself. The effect of this technique is ... odd. The music is not really going anywhere, it is rather rotating or unfolding and refolding in space. This is why Messiaen liked it.
UPDATE: I didn't quite get to explaining why Messiaen's rhythms were "non-retrogradable". If you compose a sequence of note values that read the same forward and backward, then, of course, this pattern is non-retrogradable, because it reads the same forwards and backwards.
He combined this idea with the other one, modes of limited transposition, which has a similar kind of invariance. A mode of limited transposition is a collection of pitches, a scale or mode, as it were, that possesses the property of replicating itself when transposed. For example, the whole-tone scale can only be transposed once before repeating itself:
Another example is the octatonic scale, consisting of a whole-tone followed by a half-step repeated. It can only be transposed twice without repetition:
Messiaen discovered a number of other modes as well with more transpositions, but still limited. The theorist Anthony Pople has created an ingenious chart that shows the modes and their relationships. Mode 1 is the whole-tone scale and mode 2, the octatonic scale:
Have a look at the third of Ken's posts for the same modes presented in a different way.
Messiaen was of course well aware of the historical background to these two ideas--he was a brilliant scholar and analyst. Retrograde melodies and rhythms are very old, but even the modes had precedents. He would have known of Debussy's use of the whole-tone scale, which was also used by Dukas, but he also knew (which few others did at the time) of the use of the octatonic scale by a number of Russian composers including Rimsky-Korsakov, Scriabin and Stravinsky, but also Ravel. Messiaen used the modes in sometimes bewilderingly complex configurations. Here as an example, is the early organ work "Les eaux de la grâce" from "Les corps glorieux":
What you are hearing are three lines, one for the right hand, one for the left and the bottom for the pedals. Each line is differentiated by mode. The pedal part uses the whole tone scale (mode 1), the right hand, playing the chords, is in mode 2, the octatonic scale. The left hand line is in mode 7. Here are the first eight measures of the score:
I suppose you could call this "polymodality". This kind of very clever complexity is why so many young composers were attracted to his music just after the war. But at the same time this is deeply spiritual and even richly sensual music, which is why it also appeals to many non-musician listeners.
Stay tuned for more posts on Messiaen!