Schoenberg in Structural Functions of Harmony views music as a swing back and forth between Apollonian and Dionysian epochs. Epochs of standardization and epochs of artistic liberation. That's not surprising, and it is surprising. Not surprising because he steals the idea from Neitzsche, and Schoenberg is just the person to do that. Surprising, because Schoenberg clearly in other places wants to view his atonal breakthrough of the 1920s as the capstone of musical progression since the 18th century. Yet here, in a more honest assessment, he's viewing the Second Viennese School (his school) as akin to the First (Mozart's and Haydn's) - standardization and regularization. Schoenberg, in the end, is sort of a mess. He's really an expressionist, a Wagnerian romantic on steroids, and it seems like he tries to mask it in 12-tone music, but it just comes off angsty, like his early tonal works. (Webern, oddly, doesn't come off as angsty - humorous, perhaps - but maybe that's my subjective opinion.)
But Schoenberg isn't whom this post is about.
Music history courses see the Middle Ages as a vehicle for getting us from monophony to the "tonal system" of music. It strikes me right off the bat as a bad way to approach any field of history - seeing it as another link in the chain that eventually leads to where we are in history. That's chronological snobbery, if anything is.
Modern music history really treats Medieval composers as if they're desperately groping to find the authentic V-I cadence. If only they could, they'd finally be out of the modal system they're in and into the system of chords and harmony that'll give us Bach and all that good stuff.
I was sitting in on a music history class at a big name university just recently, and I saw this happening. The professor showed the class how a typical V-I cadence results from the rules of species counterpoint. And it works perfectly well - imperfect intervals resolve to perfect ones, and we go from the bare-bones Medieval cadence to a tonal cadence you might hear in Bach. And so, naturally, we assume that the Middle Ages experienced just such a shift.
That's silly, though. One needn't listen to much hoquetus to know that these Medievals know exactly what they're doing with harmony. They're not kids at it. Maybe we just ought to consider the possibility that they choose the system they choose not because they can't come up with something better ("better" as defined as "more like the modern system"), but because they want to. They have a reason for doing the things they do, and a reason beyond, "We're having trouble figuring out how to make this sound natural."
What about the clever induction of the V-I cadence from species counterpoint? One has to remember where this comes from. I don't know - I don't have any sort of scholarship on this point, but it can't be from someone much earlier than Johann Fux. What does that mean? It means that this represents an "Apollonian" analysis of a "Dionysian" epoch. Fux is a regularizer. He's looking back on a period of relative freedom and imposing rules on it. That's what those darned Apollonians do.
That's my theory anyway. You all know this blog is me throwing out "theories", most of which are wrong, all of which are unproven. But let me go to college and try to find out if I'm right.