Dissertation Index

Author: Lam, Nathan L.


Institution: Indiana University, Bloomington

Begun: August 2013

Completed: July 2019


Diatonic modes reemerged in the nineteenth century as an extension of common-practice
tonal harmony. The existence of many potential tonics within a single diatonic scale creates a
rich ambiguity between “relative modes,” which I theorize as relative diatonic modality. A
note’s relation to the tonic is represented by scale degrees, and diatonic positions represent the
analogous relation to the diatonic scale. The concept of diatonic positions is drawn from la-based
minor solfège, which is widely used in music education but not in music theory. In relative
diatonic modality, the fuzziness of scale degrees combines with the clarity of the diatonic scale
to create a restful centric and harmonic pluralism; and this kind of relational richness and
experiential pluralism are simply unavailable in the major and minor modes alone.
Ordered chronologically from the early nineteenth century to the mid twentieth century,
five case studies explore the theoretical ramifications and analytical fruits of relative diatonic
modality. The first case study introduces Reicha’s “new harmonic system,” one of the first
experimental theories in the 1800s to discuss diatonic modes. With a focus on Beethoven’s
Heiliger Dankgesang, the second case study examines the seeming ability of the lydian mode to
conform to common-practice harmony. The third and fourth case studies explore diatonic-modal
music inspired by the French chant revival and English folk-song revival, respectively. The last
case study focuses on the rare, dissonant locrian mode and its peculiar treatment in the twentieth
century. Two threads run through all five case studies: (1) the dynamic balance between multiple
tonics and a single scale that relative diatonic modality engenders; and (2) the rich compositional
treatments that composers find when availing themselves of these special harmonic and melodic

Keywords: diatonic, scale, solfege, tonality, modality, ambiguity



Part I: Core Theory and Analytical Demonstration
Chapter 1: Relative Modality in Holst’s First Suite

Part II: Modal Exploration in the Early Nineteenth Century Chapter 2: Reicha’s “New Harmonic System”
Chapter 3: Lydian Modes and Leading Tones

Part III: Revivals in the Late Nineteenth Century
Chapter 4: Gregorian Tonality
Chapter 5: English Folk Song

Part IV: The Last Mode in the Twentieth Century
Chapter 6: Locrian Rarities




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