Symbolism

    Symbolism was a reaction against realism and naturalism, it favored the spirituality, imagination, and dreams, and largely rejected the everyday world.

Many symbolists were drawn to the area where the religious and the sexual meet, decadence (luxurious self-indulgence, bordering on and sometimes spilling over into actual immorality), Going beyond decadence into evil and even Satanism, altered states of consciousness, brought on by drugs, absinthe, religious meditation, intense emotionalism.

Symbolism in Music

        Symbolism entails a relation between two different kinds of experience, one somehow pointing to the other, and this is a type of relation that music presents in remarkable variety, for music is an extremely intricate activity. 

What is symbolic for the composer may not be so for the audience or the performer, and the historian also finds his own kinds of symbolism in music. Symbols even can be thoroughly personal. For music involves not only auditory symbols: melody, harmony, rhythm, tone-color, structure, dynamics, etc. but visual ones also, in its instruments and performers and notation. Many of these symbols are extended as a whole musical work; others are brief word-painting.

         The Austrian composer Arnold Schoenberg scored one of his early attention-getting moments with Pierrot Lunaire, based on Symbolist poems by Albert Giraud, and written for a female vocalist using Sprechstimme (speech-song), accompanied by five instrumentalists on eight instruments: flute/piccolo, clarinet/bass clarinet, violin/viola, cello, and piano.

Here's a video where we can watch an interpretation of Pierrot Lunaire:

References: Symbolism in music by Edward Arthur Lippman