When musics from all cultures of the world are considered, rhythm stands out as most essential. Unfortunately, rhythm, despite its musical importance, has been less studied than melody and harmony, the history of Western music being primarily a history of pitch. This neglect has been especially unusual because with music being a temporal art, rhythmic information is, if anything, more fundamental to musical understanding than pitch information. To study rhythm, however, is a difficult task because an accurate, generally accepted definition of rhythm does not exist. It has been further complicated, especially in the 20th century, by theorists and composers who have individually preferred to acknowledge only one of the many aspects of rhythm due to their own personal aesthetic.
Plato, in The Laws, arrived at his own general definition that rhythm is “the order in the movement.” This order may by conceived (rhythms comprehended mentally) or perceived (rhythms that originally resulted from human activity). Usually it is recognized that there is rhythm when the listener can predict based on what is perceived, anticipating what will follow. Essential in the rhythmic concept is that the perceiving of early events in a succession creates anticipation concerning later events. The paradox, of course, being that one can more or less prepare for what is to follow in both rhythmic and arrhythmic music. At one extreme, there is the successive repetition of a simple pulse or ostinati patterns, and at the other, a series of random, or seemingly random, patterns or long static episodes. The anticipation is associated with the organization within the duration. Therefore, musical rhythm, in its broadest sense, can be regarded as everything belonging to the temporal quality or duration of the musical sound.
By the twentieth century, Western musical conventions of rhythmic organization were increasingly disregarded, and the drastically diverse approaches by composers throughout the century have not led to a reamalgamation into a common rhythmic practice. The expressive rhetoric and goal-oriented organization of European nineteenth century music were no longer considered the only standards. In America, during the first two decades of the twentieth century, composers, like the early mavericks Charles Ives and Henry Cowell, developed a national musical awareness and a sense of independence from their European colleagues. Their approach to complex rhythms and rhythmic organization established an experimental trend that has defined most of American music in the twentieth century. Perhaps distrustful of the self-indulgent impulsiveness associated with romanticism, composers by the 1920s became more interested in the actual processes of the creative act especially the control and manipulation of the materials through precompositional planning.
During the 1950s, two opposing methods of composing were firmly established: integral serialism and indeterminacy. The twelve-tone method of the Second Viennese School had become widespread, and by the 50s, in both Europe and America, the concept on which it was based was applied methodically to all musical elements. The result was an extremely complicated, rhythmically intricate music and sounding, ironically, quite random and arrhythmic. It was criticized incessantly because the logic behind the piece, which was supposedly the most important aspect of the composition, was not discernible; its intricate metrical procedures concealed. Indeterminacy attempted to remove a composer’s intentions from a composition. Rhythmic events for the most part did not observe any metrical pattern. Within a designated duration, the composer could arrange events in time to any degree of spontaneity, irregularity, or complexity, or encourage the performer to take the responsibility for decisions about the temporal placements of sounds. Indeterminacy was seemingly the antithesis of serialism but produced basically the same results: complexity and confusion; the further disruption of pulse as a perceptible means of rhythmic measurement; and the renouncement of subjectivity, personal choice, and intuition.
With progress, there is a tendency to create a high density of musical events within a relatively short musical time frame, to saturate musical space and meaning. Serialism and indeterminacy can both be considered the mannerist style of twentieth-century Western musical progress, and history has shown that after a period of rhythmic complexity and disorder when additional embellishments seem impossible, there is a desire to start over with the basic elements of musical composition. The reaction to the rhythmic attitudes of both serialism and indeterminacy resulted in minimalism, which was equally modernistic and experimental, and whose fundamental characteristics, by way of conceptualism’s limited approaches, were in place by the early 1960s: repetition, regular pulse and a drastic reduction and simplification of means. What began as a strict approach to regular pulse has prospered into a highly adaptable method of composition that has had a profound and continuing impact on musicians of the past three decades up until the present day totalist composers. Most totalist composers continue to apply minimalism’s and rock’s regular, driving pulse, on which they build a complex set of polyrhythms. The audible conflicts between the polyrhythms and the steady beat are essential and not obscured by rigid, objective compositional devices.
The first century in the evolution of jazz, a music which inhabits a realm somewhere in between America’s concert hall and popular traditions, parallels many of these developments and the various sub-genres within jazz are largely definable by their different approaches to rhythm.
While the differences between these different musical ideologies have divided musicians, critics and listeners throughout the past century, similar conceptualizations largely based on a new attitude about rhythm, point to a distinctively “American” approach to the creation of music.