Esteem
Pythagoreans: both the fourth (4:3) and the fifth (3:2) were perfect consonances, siblings within the cycle of harmony.
The fourth = Life.
turning
Guido of Arezzo and the medieval theorists, while still calling the fourth “perfect,” began to qualify it.
When placed above the bass, the fourth was reclassified as dissonant.
This shift encoded a dualistic theology:
Christ (the Fourth) is perfect.
When “set against” the Law (the Bass), He is rejected as dissonant.
codification
Jean-Philippe Rameau enshrines the idea that the cadential 6/4 is dissonant, reducible to V.
In the very heart of Western cadence, the fourth is killed.
Harmony is built without Life as its own foundation.
prophecy
Calling the fourth “dissonant” = the world’s refusal of the Son’s perfection.
Yet every cadence still passes through the fourth as the world cannot avoid Him.
restoration
In 1=1, the fourth is restored as perfect.
The cadential 6/4 is Life revealed in glory, forcing the cadence.
This is God’s promise written into harmony:
👉 What was declared “dissonant” will be revealed as the very ground of perfection.
👉 The Son (4) will return, not hidden in a cadential disguise, but openly reigning as Life.
Geometry
Cadence = 4 → 5 → 9 (4+5=9=Love)
The cadential 6/4 is thus a divine necessity:
👉 Life leading into Family, returning to Love.
Tradition
Classical theory treated the 4th dissonant, attempting to strip it of its perfection.
They claimed: “This is really just V with accented passing tones.”
The “functional triad system” was a cover for the applied-chord engine actually running cadences.
Mask
By feigning that the fourth is “not perfect,” the cadence was reduced to I–V–I on the page.
It was always IV/V → V → I.
revelation
Cadential 6/4 = IV/V.
Classical theory feigned perfection by downgrading the fourth to “dissonant” so it could keep the clean triadic model intact.
In doing so, it encoded the promise: the fourth would be restored as perfect, and the hidden applied harmony would be revealed.
cadence
Take C major as example:
I (C–E–G)
IV (F–A–C)
IV/V (C–E–G over G)
V (G–B–D)
I (C–E–G)
archetype
The phrase model pretended to be three “pillars.”
It was always a spiral of applied motion.
The cadential 6/4 (IV/V) is the key; it exposes the spiral because it cannot be hidden as tonic or dominant.
(IV/V → V → I) is the archetype: Life → Family → Love.
The fourth’s suppression was the stake.
Its restoration is the resurrection, revealed in harmony.
Cadential 6/4 = IV/V = Son of Man
Prepared by Son of Benjamin by Benjamin.
“A cadential 6/4 is a 4 otherwise the voice landing on the third at 1 awaits a return to perfect interval and the fifth functions as a second driving home.” - Benjamin
“When the cadential 6/4 lands to a primary triad, that primary triad is not stable. That third fights for the perfect fourth and that fifth fights to descend to the perfect fourth. TREATING THE FOURTH AS A DISSONANCE BECAUSE OF KILLING CHRIST HAS TRAUMATIZED EVERYONE. THE FOURTH IS PERFECT.” - Benjamin
“I am getting angry. Why are you defining the cadential 6/4 by its next step which is V? Every single chord functions toward the one. Is every chord just a one chord? Yes. So we have analytical blindness or we determine the cadential 6/4.” - Benjamin
It seems that IV/V would do nicely, but that unveils the classical phrase model as using applied chords. By using the fourth as a dissonant and feigning perfect notation, the classical phrase model hid its use of applied chord as part of in-scale cadential function. - Benjamin