But however uninhibited and loud his music could be, it rarely descended to vulgarity. Berlioz objected to using musical thunderstorms and twittering woodwind birds merely as special effects. He stressed that music imitating nature was appropriate only when it served a musical purpose. This purpose could simply be contrast or dramatic effect, as long as the drama was motivated by the musical form, not the other way around. Berlioz was concerned with the expressive potential of music, which he felt was greater than that of poetry or art.
Music can be expressive and dramatic in itself, without reference to stories.
Mozart and Beethoven wrote a great deal of highly expressive music that told no tales. Even when Berlioz was depicting a witches' dance, he had to concentrate on purely musical matters such as rhythm, melodic shape, patterns of rhythm and melody, the plushness or astringency of the harmony and the special sounds of each instrument at his disposal. The score would exist, make a strong effect and be intelligible as music even if Berlioz had not attached to it the image of a witches' dance. Berlioz did not abandon traditional musical forms. The work mixes an imaginary autobiographical story with music.