Ethan Hein discusses Michael Jackson's "Man in the Mirror", which has probably the single longest unresolved plagal cadence in the history of pop and how it extends a harmonic precedent set up earlier by Stevie Wonder

https://www.ethanhein.com/wp/2025/modulations-in-man-in-the-mirror/

Just a couple of brief thoughts here.

That C# fully diminished seventh chord I have always heard as a secondary leading tone chord.  Yes, I know, it can be thought of as having a secondary dominant function and I agree with Ethan about that.  The flavor, though, is secondary leading tone chord.  The C# fully diminished seventh chord rising to the D7 with the split third F natural up top sounds right, and the reason I hear the C# as just that is I sat down and played through that C# dim 7 chord as if it were a standard secondary dominant chain A7 to D7#9 and it just sounded all wrong.  From a linear and contrapuntal standpoint the C# secondary leading tone chord is the right call.  I know theorists may differ but that's my conviction.  Building a secondary leading tone chord on an augmented fourth is still bluesy.  Ethan's discussed the use of diminished seventh chords in blues in the past and I had a response post highlighting a spectacular passage from Villa-Lobos planing fully diminished seventh chord shape down the entire guitar neck.  You can go look that up if you like.

So first thought is about the secondary leading tone chord that's a fully diminished seventh chord.

That G to A flat modulating reminds me of Stevie Wonder at two different levels.  The semi-tone modulation resembles "Living for the City", which I have long considered "Man in the Mirror" to be a spiritual counterpart for.  Stevie Wonder's song is about the desire to change the city (and I can't resist throwing in references to the Christian anarchist Jacques Ellul's The Meaning of the City because I am a bit of a fan of him). I think of the final chord in Stevie Wonder's song as the grand unresolved neapolitan substitution in a never-resolved plagal cadence.  It's the "Amen" to a Gospel song where the IV chord is never allowed to reach the I because this song is about what we have now, not an eschatological end to toil and suffering that shows up in the major prophets of the Hebrew Bible (Isaiah, obviously).  

"Man in the Mirror" has a modulation up a semitone but then there's that sprawling D flat.  Ethan Hein hears it as if we've modulated into D flat major with a lydian element.  I have always, and I do mean always, heard the song as ending with a spectacularly long unresolved plagal cadence.  The reason I hear it that way is because of how long he band hammers the key of A flat with chorus right up to that D flat chord.  There's a whole minute of cycling through choruses in A flat, replete with dominant prolongation passages.  When the D flat chord hits at 3:51 it's obviously the IV chord after so many V-I resolutions in A flat major.  That harmonic memory doesn't go away for Michael or the band, as I hear it.  If you are sticking for a long time on a subdominant chord but keeping the music strictly diatonic then lydian would be the literally natural sonorous implication of staying on the subdominant.  Lydian is an asymmetric scale and the inversion of phrygian, the augmented fourth can suggest a secondary leading tone to the fifth of the scale but in this case the augmented fourth on a subdominant chord is just the leading tone of the key.  I mean, at the risk of noticing Crouch did the choral arranging, when there are so many obvious nods to Gospel I think that's an extramusical but still musical indication that a giant unresolved plagal cadence is the best way to understand the song "Man in the Mirror".  

The song would lose its emotional potency if you ever actually resolved that D flat chord to A flat, and it would become comical if the D flat went to E flat and then to A flat but cycling through the usual I, IV and V via secondary leading tone chords previously mentioned is what we've had going on through the song until this closing D flat major chord.  It's not that the song has exactly modulated to D flat so much as that the various harmonic prolongations that have shown up earlier in the song and the lyrics cement an idea that a change has to be made but the change has to come from you and me as Michael is singing to us, for us, and for himself performing the song.  

I didn't particularly like Bad when it came out and it was the beginning of the end of my fondness for Michael Jackson's music but this song was one of the best songs on the album and it still works decades later.  It sure holds up better after all these years for me than "Speed Demon" or "Dirty Diana".  I'm not saying you can't like the album, just reminiscing about feeling disappointed and underwhelmed by the album when it came out.  It still had good songs but it did come after Thriller.  I'm reminded of something I said to a friend about a movie I won't name that was a sequel, which is "Bitterly disappointing is not the same as actually bad."  

But I digress. I think "Man in the Mirror" ends with a gloriously unresolved plagal cadence and that it takes up thematic and musical elements I hear in "Living for the City" to similar effect.  

So for me there is only one modulation in "Man in the Mirror" but theorists can (and should) debate this point.  The song's use of harmonic rhythm and phrasing is why, though that's based on what my ears tell me as I don't actually have a score for this one.  I used to sing in choirs in college and at church and maybe I should concede that if you have done enough singing in church you can (or may) hear things like the end of "Man in the Mirror" as not having a modulation because of performance experience.  I can see how that D flat could be heard as established as a new kind of tonal center and I don't really dispute that, I just hear it differently because of my background as a classical guitarist and volunteer church musician who also has some background in choral music. 

I think I may have touched on having some familiarity with Baptist and Methodist and Pentecostal hymnody in the past when discussing harmonic rhythm and implied rather than "played" harmonic material in performance in a response post to Ethan Hein's discussion of a song by John Lee Hooker.  Hooker's performance of "Ezekiel Saw the Wheel" uses oblique motion on the guitar to establish IV-I relationships that are more plied than "heard" through a combination of the inflections of his singing and muting the subdominant harmonies as he vamps.  

It's as necessary for "Man in the Mirror" to never reach its tonic as it is for "Living for the City" to not reach its tonic at the end for is musical and lyrical point to be made.  Somewhere, somehow I heard a version of Stevie Wonder's song where that neapolitan chord resolved down to its expected tonic ending and it felt weirdly tossed off an anticlimactic.  After all that came before in the song to actually reach the tonic after such a dramatic subdominant prolongation becomes a musical and lyrical bad joke that says, "Well, yeah, everything's magically better now and nobody actually needs to change at all."  

Never-resolving chords happen in classical music, too.  An example of an unresolved half cadence (which I actually hate) is Virgil Thomson's arrangement for chorus and piano of "How Firm a Foundation". One of the most memorable examples from my own choral singing background is that gorgeous unresolved F sharp dominant seventh with an added 9th (which I love) is at the end of Durufle's Requiem. There the unresolved dominant ninth chord obviously symbolizes the never ending rest of Heavenly bliss from Requiem mass.  Unresolved chords can have all kinds of text-painting functions in vocal music and some of the most memorable and riveting endings in pieces of choral or vocal performance come when the "end" is deliberately impossible to resolve for the sake of expressing a point made in the text of the song, whether it's  Durufle's "in Paradisum"; "Living for the City", "Man in the Mirror".  When you know what textual point you want to make in your music then there are times when the where, when, how, what, and why of breaking every harmonic "rule" in songcraft dictates that you break allegedly sacrosanct harmonic rules to respect the point of what the words are saying is the point of your song.  

Ergo, the massive unresolved plagal cadence in "Man in the Mirror", as I've been saying through the whole post.  

Matiegka's solo guitar sonatas: his use of the V-IV progression and not resolving his leading tones upward--maybe nobody told him not to break those "rules" of counterpoint and harmony in 1808 and 1811

One of the staples of music theory courses has been to tell students that in classical harmony (more like 18^th century “common practice” there are a bunch of rules you aren’t supposed to break.  Avoid parallel motion or direct motion is one of the basics of bad counterpoint.  Another rule is, so many of us have been told, you always resolve the leading tone of a major scale upward to the tonic note.  The big one in harmony is that you’re not supposed to proceed from the V chord to the IV chord. 

 

Another staple in music courses has been that blues “broke all the rules” of classical music or just didn’t follow those rules. 

 

I regard both of these as unhelpful canards.  One of the curious things I’ve discovered after a decade of going through the solo guitar sonatas of Wenzel Thomas Matiegka is that he ostentatiously “broke the rules”, two of the allegedly big ones about the melodic direction of the seventh scale degree in major keys and particularly the one about how V never proceeds to IV. 

So let me demonstrate that these so-called rules were already being broken in 1808 and 1811.

Ethan Hein blogged on Miles Davis' "So What", my thoughts on the elegance of symmetrical scale and the Neapolitan substitution that keeps "So What" from being generic art rock i-IV groove

http://www.ethanhein.com/wp/2020/so-what/

Ethan Hein does an excellent job breaking down what makes "So What" work phrase by phrase and lays out its AABA form.  For those with more of a classical music theory background what should jump out about that form is that it can be thought of as a kind of rounded binary form.  I don't want to digress into how familiar Davis was with both jazz and classical music because I want to jump straight into why this assymetric form is so crucial to making "So What" a magnificent composition.

The AABA form has two different aspects that make this simple composition pregnant with possibilities. The first is that the composition can feel like a kind of cut-short 12-bar blues by way of hypermeter; every two bars of 4/4 can be thought of as halves in the call and response phrases.  There are multiple levels of 4-to-the-bar going on.  Davis doesn't do the conventional V-I finishing pattern that would come if this were a conventional blues and lets the AABA continue whereas a more blues-traditional form would have had an AABAB'A pattern that gave us the three-phrase-at-the-macro-level pattern that's common in archetypal 12-bar. He was playing with a norm in phrasing and phrase-length that, if you don't have that in mind about how a blues "should" sound, won't make sense to you. Or as Hepokoski and Darcy put it in Elements of Sonata Theory there can be norms of form or gesture or listening that are in the background that can guide our understanding of the conventions or "deformations" of a musical work that are nowhere in the foreground of the musical work we're analyzing. Now I'll get to the second thing that stands out for me about this work.

"So What", within its AABA has an asymmetric phrase structure that is amplified by a harmonic substitution that counteracts what would be a pedestrian symmetry within the mode if no substitution were made.  I'm talking about the formal assymetry of the D dorian to E flat dorian.  That E flat dorian section is paradoxical because, of course, the dorian mode is symmetrical and if you invert it the mode is has the same intervals going down as going up, unlike, say, an inversion of the intervals of the phrygian mode that will give you the lydian mode.  The risk of using dorian is that because it's a symmetrical scale if you did do a traditional i-iv blues change there would be no momentum at all, which is why Davis' decision to do a neapolitan substitution that pivots dorian from D to E flat is such a brilliant compositional move.  There's still a "IV" function and it's still in exactly the place it ought to be if we were hearing a 12-bar blues but it is an abrupt Neapolitan substitution that keeps the dorian scale above the new-found harmony.  

Now dorian in jazz and rock has long since become commonplace.  If I were to pick a favorite long-form dorian-based piece it would be Frank Zappa's "Nine Types of Industrial Pollution" at the start of Uncle Meat and "King Kong" at its end.  Those are cool as they go but when you hear them you hear that there's a i-IV floating-in-space vibe.  Through the 1960s and 1970s the dorian i-IV progression became a thorough-going psychedelic/art rock cliche, perhaps nowhere more prominently used than at the starting song of Pinkfloyd's Dark Side of the Moon, "Breathe" I wrote about the use of the dorian mode and the i-IV progression within it as a way to understand the concept album all the way back in 2007. Now I'm not meaning to suggest the mode was really what they were consciously thinking through, I think music theory in general is too post hoc to be used to say something like that.  Plus I kinda figured everyone in the band was high as a kite and that there was more of a literary and "hey, this vamp sounds cool" vibe going.  

Well, before psychedelic rock and prog rock beat the i-IV groovy dorian i-IV thing into the ground Miles Davis didn't want to have a work that has become a touchstone in modal jazz be "that" modal. He introduced an elegantly simple and brilliant substitute for what would have been the i-IV in a stereotypical dorian progression with a flat II (i.e. Neapolitan) substitution.