Anand,
Where did you get the impression that I had stated either Mahler or Beethoven were "old-fashioned"???? Not my words my friend, but William's. I've loved Mahler since I first heard the early Bernstein recordings with the New York Philharmonic. I'm of the opinion that Mahler, in many ways brought the symphonic tradition to it's culminating point—a true progressive. Beethoven... well, let's talk about those last few string quartets of his, not just the big fugue. That was music that was considered to be avant-garde in its day. Debussy? Better to compare Debussy to Vincent D'Indy if you want a more useful comparison... or, as I did, in comparison with his French compatriot, Auric.
I think it's silly to compare the music of Philip Glass and the other innovators of his time with those of earler eras. Each artist is working with the materials at hand, which are profoundly the cultural conditions of their time. The American minimalists were responding, to some extent, to the chaos that John Cage had led contemporary music into in the U.S., as well as the chaos of complexity that total serialism had led to in Europe at the time. Both approaches were based on the idea that music can be largely precomposed according to some kind of process, be it throwing dice, mapping musical pitches to a star map, or devising a sequence of numbers that map to every parameter of the music. Steve Reich's response to this, as he wrote in his essay Music as a Gradual Process http://www.bussigel.com/systemsforplay/wp-content/uploads/2014/02/Reich_Gradual-Process.pdf , was that the processes in the music should be able to be heard.
Of course Ligeti... but again, to compare his music to that of the so-called "minimalists" is to compare frogs with grandmothers. Better to compare his music to his fellow composers of the Darmstadt school... Boulez, Nono, Stockhausen, Berio, Kagel, etc. That makes sense and is actually pretty interesting if you look at Ligeti's standing in that group at the time and who's music is still left standing in the present. And if you don't like their music, fair enough. But let's not take the attitude that we can flatten history out and compare the Gregorian Chants of Perotin to the string quartets of Brian Ferneyhough and come to the conclusion that one is "better" than the other. They're not. They're the product of their time—their music is the way each composer thought about music in a creative way—both innovators in their own right. I can say I prefer to listen to Perotin over Ferneyhough for a variety of reasons... use of consonance, voice vs. instrumentation, level of complexity, their respective place in the history and evolution of European art music, etc., but to come to the conclusion that one is better than the other? I don't think so. I can only say I enjoy one more than the other and try to understand why, hopefully in a way that can inform my own musical creativity.
About your test. Which tonal tradition are you speaking of? Since when does one have to be proficient at the harmonic practice of a particular era to be given the stamp of approval for music being made now? Functional harmony? Palestrina? Bach? Haydn? Or the triadic harmony articulated by Riemann that seems to better describe the chromatic practices of the late Romantic composers? Do we need to be able to reproduce a sculpture in a Hellenic style to a bona fide sculptor? I think it's interesting to consider that Glass was taken on as a student by Nadia Boulanger in Paris. She was not known to suffer fools gladly, or take on just any student, having refused Astor Piazzola among others.
Somehow people get the idea that Glass is some kind of untutored hack. I think you should be careful before judging the level of education and musical knowledge a composer has. He, apparently, wrote a substantial amount of "traditional" music in his youth which was destroyed precisely because it lacked an individual voice. And please consider, for instance, the following text shows some of Glass' thinking about the harmonic relations in his Einstein on the Beach work:
"Glass describes one of the main harmonic ideas of the work is taken from the closing section of “Train.” He states that this particular progression resembles a traditional cadential formula, though presented with an altered chord in the middle that serves as a pivot chord, ultimately leading to a resolution of the cadential figure a half step lower than expected. The harmonies of this thematic idea are F minor – D-flat major – B-double flat/A major – B major – E major. Thus, the progression begins in the key of F minor and ends in the key of E major, with the B-double flat/A harmony serving as flat- IV in F minor and IV in E major.27 This particular analysis of the pivot chord in this progression is taken from Glass’s own writings, presumably to show how this particular harmony would function if the context remained in the realm of F minor. However, since this harmony never appears in the exact form of B-double-flat major, only as A major, a better understanding of this harmony in terms of F minor is that it is a chromatic mediant in this key. As the progression moves forward, its new E major context becomes clear, so that this A major pivot chord can also be heard as IV in the new key."
So, perhaps he's not describing the harmonic structure of one of Handel's oratorios, but you've go to admit, there's a level of sophistication in the thinking here about harmonic structure—an awareness of the way tonality can be manipulated, its ambiguities leveraged.
If you're interested in knowing more about this you should read the whole piece. It's a good read:
https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1072&context=musicstudent
Anyway... I don't know why I'm defending the music Philip Glass here. I don't really much of it, but I wish there were a higher level at which the dialogues on music could be shared here. Not with people throwing out misinformation, putting words in other's mouths, and using language like "bullshit" to describe the work of others. If we have something useful to say... we should say it, in an intelligent and respectful way. Back it up with evidence, not just hearsay and "I know what I like" subjective statements. That's the issue with the sorry state of our post-modern era. It all comes down too often to "what I like" instead of taking the time to understand how we got here and how we might move forward based on that realization of the deeper meaning of such a divine thing as music.
OK... I'll shut up now (for the moment).... ;-)
Kenneth.