Atonality is a system of musical organization which places no greater emphasis on any one note than any other. Traditional Western music has a tonic — the first note of the scale — and a dominant — the fifth note of the scale. These two notes are used to provide a sense of beginning and ending to musical pieces. Atonality attempts to eliminate the hierarchy of tones to create a musical piece in which all notes are equal.
The system of atonality or 12 tone music was pioneered by Arnold Schoenberg, who was born 1874 and died in 1951, and Anton Webern, who lived from 1883 to 1945. During this time period, the concept of conflict theory, paralleled in Marxist philosophy and the ideals of communist societies, was also taking form. Its basic tenets held that if an individual is greater or has greater possessions than another, others are victimized. Therefore, a truly just society would have members who were equal in every way. Just as philosophers, psychologists, and politicians tried to implement the ideals of conflict theory in society, composers tried to reflect these ideals in music.
Since it is centered on a single note, a key signature is the opposite of atonality. For instance, in the key of D major, the piece will probably begin and end on the D major chord. The result is music which has a definite linear plot to its sound, much like the plot of a novel. Any musical suspense is resolved by the end of the piece.
In a typical key signature, the tonic and the dominant are used most frequently. The constant musical reminder allows the ear to organize other sounds in reference to the tonic and dominant. Atonality uses no note more frequently than another.
Strict atonality, sometimes called "12 tone" music, uses each of the 12 notes in the chromatic scale before repeating any other note. Similarly, no note is held longer than any other or played louder or higher, as this may create a sense of musical hierarchy. Achieving a purely equal, or democratic, piece of music is extremely difficult, and some might say that regardless of the composer's intentions, it is impossible to accomplish.
Atonality uses other musical criteria to form its linear plot. There may be tempo or dynamic changes or specific instrumental techniques or groupings of instruments. Atonality is actually a popular form of music in the film industry. It is very versatile and can be used to reflect and intensify on-screen emotions as well as to foreshadow or support the plot of the film.