"The eternal mystery of the world is its comprehensibility." (Albert Einstein.) In the same way, the music of Bach is comprehensible but why this is so, remains a mystery, that is not explained by musical analysis. The music of Debussy is entirely logical, but it is very hard to uncover the logic, although the sensitive listener feels clearly that it moves on the same tonal dynamics like any other great music, like Bach's. With music, the comprehensibility is located at a level, different from sonic art. For instance, through-composed serialism (an early form of sonicism) is entirely logical but in the same time, entirely incomprehensible - that is, from a musical point of view (from a sonic point of view, the concept of 'comprehension' is irrelevant). Music is aural mathematics, but in a different way from pure mathematics, which is about proportions and relationships; in music, the proportions and their relationships are fluent, shifting, and including both provisional and anchored articulation points, and leaving an open space between lines and points which makes it impossible for the composer to precisely 'calculate' his piece.
Where mathematical method is applied literally, as Schoenberg tried in the twenties of the last century, all those ambiguous and floating qualities of musical mathematics disappear. Hence the impression of both stiffness and chaos of Schoenberg's serial works.... he tried to create a music that would be entirely logical and comprehensible but sought those qualities on the wrong level: on the literal one, and he was followed by a lot of composing people who found such approach less hard to grasp than the other, more fluent and ambiguous logic, which requires not rational but intuitive and sensitive capacities.