The Logic of Music

As I noted here a while back, I have long wondered at the logic of music and how it is different from every other logic. Music is organized sound, arranged in phrases, involving harmony (the sounding of more than one tone at a time), melody (the arrangement of a series of tones sounded one after the other), rhythm (the timing of music arranged by repeated duple or triple beats), and counterpoint (more than one melody sounding at the same time). The phrases in traditional music are the equivalent in length to how long a singer could sing before taking a breath. And I’ve noticed when I’m playing the piano or guitar, I breathe out during the phrases and take a breath between them.

Since the time of Johann Sebastian Bach, tonality has been a determining feature of most music. Before Bach’s time and the development of the tonal system, western (that is, European) music was modal, written using one of the seven scales possible on the white keys of the modern piano. The resulting modes are named Ionian (beginning on the note C), Dorian (beginning on D), Phrygian (beginning on E), Lydian (beginning on F), Mixolydian (beginning on G), Aeolian, (beginning on A) and Locrian (beginning on B). Two scales of the tonal period are also modes, the Ionian (the modern major scale) and the Aeolian (the modern minor scale). But composers since Bach’s time have raised the two highest notes of minor scale when a melody is ascending and lowered them when the melody is descending.

These days we hear almost no music written in the modes. The only exception I’m aware of is the song “Greensleeves,” which has been turned into a Christmas carol named “What Child Is This” by changing its lyrics. It’s written in the Dorian mode, but sometimes in performance, that mode is changed to the normal minor by raising the seventh tone when the melody is travelling upward. There are another half dozen or so very old carols that are modal rather than tonal.

More next time.

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