This is always a curious topic and one that I have been considering lately because sometimes I visit a few forums by conservative Christians whose views I sometimes respect and sometimes disagree with. I also occasionally get books run my way on the development and evolution or demise of Western music or about Christendom and the West and music in general.
I sometimes come across statements like "tonality is Trinitarian". Well, cool, I suppose diatonic scales and equal temperament "could" be Trinitarian but I'm at a loss fot he acoustic principles and physics that exlpain that one. The ubiquitous presence of the melodic and harmonic perfect fifth seems like a case for universal conceptions of tonality until you dig into Pythagorean, mean-tone, and other forms of intonation. The whole doctrine of affections in Renaissance and early Baroque music clearly derives from the practical issues of how nasty B minor sounds on an instrument using mean-tone intoation compared to an instrument using Pythagorean or equal temperament. A piece that wouls sound like Hell, as the old saying might have it, might not sound so hellish thanks to equal temperament.
So there's that. And then there's the broader question of the connection between the medieval/ecclesiastical modes that evolved into the majorminor key stem and what connection, if any, can be established between these tonal organizational principles and ancient Greek or Hebrew music.
The case is fuzzier than some people would have you believe. I've read Aritstoxenus, who is cited as a refernce by Plato and others on the matter of music and the sad truth is is that experts in the field admit to being at a loss for what these dudes were really talking about. A decent guess is that the ecclesiastical modes may have been inversions of the Greek modes but this, too, is fairly speculative.
I'm all for Western music and tonality and I dig the music of that tradition at least as much as the next guy but the idea that tonality can be proven to be Trinitarian and Christian and that the West embodies Christian precepts still seems shaky to me. Not because I am not a Christian or don't believe that Chrsitianity is foundational to the development of Western culture. My hesitancy is based on my understanding that Christianity is global in its scope and that the differences between ancient Middle Eastern music and even ancient Greco-Roman music and the medieval musical legacies that led to the Renassiace and Baroque periods are underplayed for the sake of political expediency by polemicists interested in saying this or that musical style is less Christian than another.
For instance, modal music and tonal music are not exactly the same deal. They sound similar but that'snot the same as saying they are actually organized along the same principles. The simplest explanation of how these differences manifest is that in modal music a descending melodic sixth is rarely endorsed whereas in functional harmony from the major/minor system this kind of melodic interval happens frequently. Why? Because conceptually there is a sense of tonic over which the descending interval can be tuned. In the earlier style the melodic consideration took precedence of the idea of a home base for a key center.
"Nobody Knows the Trouble I've Seen" is not a song that you're going to find written prior to the advent of functional harmony.
Conversely, most really great modal melodies predat the Baroque era because Greensleeves and other modal melodies did not necessarily survive their, if you will, sword-point conversion to functional harmony. Most people know "What Child is This" in natural minor rather than dorian. That is one of the few modal tunes that survived the transition that I can think of, or that most of us can think of. "What Wondrous Love is This?" is yet another onee.
IT is only in the context of functional harmony that a perfect fourth could be considered a consonant interval (thank you, second inversion chords).
Why am I saying all this? Well, where the rubber hits the road is when Christian commentators say that this or that composer wrote music that defied the Trinitarian ideal of functional harmony by injecting rampant chromaticism. There are problems with this approach from a historical and musicology standpoint. The first problem is that Bach opened the floodgates of chromaticism in his generation in a way not entirely different from the way Gesualdo wrote chromatically far-out music in HIS time. Mozart and Beethoven both employed chromaticism in ways that were highly unusual for there time and then you get folks like Chopin or Berlioz. By the time the pet whipping boy of Christian conservative commentators appears, Wagner, most of the revolutions they decry and attribute to his music had basically already happened.
And then you get the slow and spotty assimilation of non-Western musical styles or the employment of ecclesiastical modes apart from the voice-writing precepts outlined from the era in which they were initially employed. Debussy did not invent dorian or mixolydian but what he did was to employ the modes iin fixed form without regarding for the intervalic strictures of the pre-Baroque era. That's what made his music sound trippy in its day. Debussy also incorpoated elements from styles where ever he dug them.
How does this connect to Christianity and more "modern" music? Well, I could write some more about that but feel like saving that aspect of the discussion for another time.