At Arnold Schoenberg let's read:

There are relatively few people who are able to

to understand purely musically what music has to say.

The assumption that a piece of music must awaken ideas of some kind, and if these do not arise, the piece of music has not been understood or is of no use, is as widespread as only the false and banal can be widespread. Here he refers to Arthur Schopenhauer's Thoughts:

The composer reveals the innermost essence of the world and expresses the deepest wisdom,

in a language that his reason does not understand.

Allegorically interpreted Olivier Messiaen:

Music is a new blood, a speaking gesture,

an unknown scent, a bird without sleep.

A music like a stained glass window, a swirl of complementary colors,

a music that expresses the end of times,

the omnipresence, the transfigured bodies,

the divine and natural mysteries.

My music is like a departure.

A transition into something new and unexpected.

This conveys feelings of fear but also hope.

It is a challenge and encouragement,

reflects sadness, peace, freedom,

Love ...

The dreams at the window for happiness,

to the gate of the soul.

In the light of the sun,

the true heart,

that sings.