It really is hard to discuss this without spewing Coca-Cola all over my monitor and keyboard, because the premise is so patently absurd on its face as to be abjectly laughable. I mean, music is a communicative medium, and so content is mandatory, not optional. IOW, if your music isn't saying something, it is saying nothing. If you have nothing to say, then keep your pie-hole shut, m-kay?
I remember the first time I encountered this form of musical nihilism (And - unlike so many today - I iknow what nihilism is, and I'm using the word correctly). It was when I was in the composition DMA program at UNT back in the mid nineties. My "teacher" at the time was a n00b composition prof named Dr. Joe Klein (I chose him because he was a n00b, and so would allow me to follow my already-set agenda), and he said - and I quote - "I don't write goal-oriented music."
Read that line a few times. Again. Let it sink in. Deep...
Are you laughing uncontrollably yet? If not, you do not understand musical composition. At all.
Music is often compared to spoken language, and this is often a perfect analog; especially when the musical medium includes song. However, when you come to instrumental music - absolute music - the analogy begins to break down. Sure, there is still phraseology present, and other temporal aspects which music and language share, but spoken language has no God-given component at the heart of it: Language is limited only by the human body's ability to sound, and the human mind's ability to comprehend. Whispers, shouts, beeps, or clicks; any sound a human can make can be used to communicate, and as long as a community agrees upon the meaning, the communication will be effective.
Outside of the given communities, however, all spoken languages are no better than gibberish.
Music, on the other hand, is a universal language: Everybody from every culture will recognize the music of another culture as music, even if they are not steeped in its traditions (This is a fact, by the way, and is not a matter open to debate).
Why is that?
Because, unlike spoken language, music has at its heart a God-given key to the understanding of it, and that key is the harmonic overtone series.
The history of Western art music is the history of the unravelling of the implications of this harmonic series.
If you were to dispense with the style-related rule-sets of counterpoint - those things which make Palestrina sound like Palestrina and Bach like Bach - you would be left with basic contrapuntal laws which the series explains:
1) Intervals in the series which are consonances and are superparticular ratios in both inversions cannot move in parallel.
2) Intervals in the series which are consonances and which are superparticular ratios in only one position may move in parallel.
3) Dissonances cannot move in parallel.
And, that's really it: All else are simply rules based on taste which can be left to the discresson of the composer.
Same goes for harmony. The first seven partials of the harmonic series spell out a dominant seventh chord, so every tonic - after it has had its day - wishes to aquire a seventh and be absorbed into a new tonic a perfect fifth below. In order to be able to leave and approach a tonic by this motion (In a triadic environment), major triads are required on I, IV, and V. These three triads make the so-called Ionian mode, or rather, diatonic tonality. The minor is simply a derivative of this: A minor third below the major tonic is the mode which yeilds minor triads on the cardinal degrees.
Further, all root motion types are related to this primordial falling fifth progression. If a falling fifth is a progression, it follows that a rising fifth is a regression, and this is so: Regressive root motions sound like they are going backwards against the natural inclination or desire of the harmony.
Since it takes two falling thirds to make a fifth (And if you use the proper circular transformations, the voices will make the same journey through two thirds as they do with one fifth), it follows that a falling third is a half-progression, and a rising third is a half-regression. This is also demonstrably true, and is a realized implication of the overtone series.
Diatonic seconds are super-progressions when they ascend, and super-regressions when they decend, because they imply a missing root a third below the "theoretical root" (Or, we could call it the "philosophical root" LOL!) of the lead harmony.
And so, all of the effects that the various root motions have can be explained by how well they conform to the primordial falling fifth progression implied by the overtone series.
No overtone series, no universal language.
That's why it is a fact - and not my opinion - that wrongly so-called "atonal music" is noise and is not music at all: Music is the art of tone setting to display philosophical aspects of the implications of the overtone series!
Ironically, the greatest philosophers of antiquity were all interested in music, and used music to explain examples of their philosophical musings. So the answer to the question, "When Did We All Become Philosophers?" would be, "From the beginning, dumbass."