Your post brings two things to mind. The first is one of my favorite movies - Amadeus. I believe it was the Duke who commented to the young Mozart that his composition had "too many notes." Maybe that was the Duke's attempt at an empirical comment on the music.
The other has to do with my obviously biased attitude about modern music. Using your denominator of Truth as the means for judging music, I find far too much music to be phony. It is sometimes obvious when music is written for commercial purposes - diminishing the art form to a commodity. The word that I have often used to describe music that strikes me as an honest effort is "authentic" - not too far from using "truth" as the measure of its worth.
In my anti-capitalist mind, music that is written solely to create commercial success is not true music. Music that appears to be written and performed for the sake of the music will more often ring true. I do confess to being more forgiving of music written to protest policies or ideas, even though it is written with an eye toward something other than the art.
I do not mean to say that all popular music is inauthentic. Sometimes a new approach to music will strike a chord with the public (pun intended) and find great commercial success. Some performers will simply find their voice in a style that is familiar and accessible. The unfortunate thing is what too often follows an innovator's commercial success. That success will give rise to several imitators, none of whom match the energy - the authenticity - of the originator. It is a simple-minded approach, but one that accurately describes my enjoyment of music.
Regards,
D-Ray