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Locrian Chord Progression: Why It Doesn't Work (And Why There Aren't a Lot of Great Popular Songs with Non-tonal Harmony)
With the diminished chord as the tonic, the Locrian mode can’t even think of establishing tonality.
To summarize, in all five of the Church modes, you can’t establish mode-defining tonality using chord progressions based on modal circular harmonic scales due to problems with the V7 – I progression and numerous other unfortunate harmonic incongruities.
So, what about claims that the five Church modes—Dorian, Phyrgian, Lydian, Mixolydian, and Locrian—are just as harmonically robust as the Ionian and Aeolian?
Here's the problem. To evoke the emotional responses that arise from the contrast between harmonic consonance and harmonic dissonance, you first need to create (establish) consonance. Major and minor triads are the only consonant chordal harmonies, which is why they are necessary to establish tonality (what we call a "key"), and why the tonic chord needs a dominant 7th, the restless, unstable chord that "dominates" tonality by pointing to the consonance of the tonic chord, creating great contrast.
Of course it isn't literally the case that the V7 chord must be present in a song—all chords apart from simple triads are actually dissonances, and serve to create the harmonic contrast with consonance that evokes emotion. As well, some great songs only have one chord, the tonic. But they have a lot of other things going on, too, such as a terrific tune, great lyrics, compelling rhythmic elements, a magnificent vocal performance, etc. A good example is Aretha Franklin's rendition of Don Covay's "Chain of Fools."
In theoretically non-tonal harmony ("modal harmony")—harmony that cannot establish tonality—it's all dissonance, no consonance (i.e., minimal contrast), not unlike the atonality, serialism, and twelve-tone technique of the early 20th Century.
There's a reason why only the Ionian and Aeolian modes survived the discovery of equal temperament and the revolution in harmony that became the Western tonal system. And why there are no significant troves of great classic songs that are both harmonically and melodically solidly modal. It's not a matter of Eurocentric "cultural bias." It's a matter of the evolved biology of the human brain, as discussed in Chapter 1.
Nevertheless, the Church mode scales—all of them—can serve as excellent source scales for creating beautiful tunes. The secret is to combine modal melodies with standard major-minor (Ionian-Aeolian) chord progressions. Chapter 9 discusses how to do this.