What is a composer for?

What is a composer for? What exactly does he do? This question has many answers, depending on the intended use or purpose of the composition. For now, I will ignore our technological age and concentrate on the 18th and 19th century. Some composers were writing music for a specific occasion. This can be something as simple as writing music for background, to cover the clatter of dinnerware in the dining room of a royal patron. This is like musical wallpaper. Boccherini comes to mind in this case. Some are writing music to support a theological position. Bach is like this. Some are trying to convey some sort of narrative line, like a literary novel. Tchaikovsky is of this sort. Some composers are linking music with political and social issues. Wagner is like this. The most difficult task for a composer is to write music that aspires to the same type of expression as poetry. These composers are trying to share inner states of experience, inner truths that require them to turn themselves inside out, baring themselves in an unshielded way to all of us. Beethoven is like this. The “sounding inwardness” of his deafness must have been very deep, practically bottomless. In this way Beethoven is the first Romantic composer. Schumann tries with all his might to link poetic states with musical expression. Mahler was trying to write his inner experience of the whole world into his compositions. The unshielded quality of the composition requires of a performer that they also turn themselves inside out and share their inner experience of the music they are performing. I'm not talking about making faces or looking up to the heavens for “inspiration” during key points of a performance. Performers who do not fully embrace their responsibility to empathize and live in the recreation of the inner states of these kinds of works are not just siding with Apollo, they are missing the point. In Rilke's first “Sonnet to Orpheus” he writes:

A tree ascended there. O pure transcendence!
Oh Orpheus sings! Oh tall tree in the ear!

Orpheus represents the artist who is always turned inside out. This is talking about “sounding inwardness” and its internal growth and eventual outward expression.