Mode (music)

In music theory, the term mode, or modus, describes a complex system of sound. It is often defined as a specific type of musical scale. However, a mode is more than just a sequence of pitches. It also includes characteristic melodic and harmonic behaviors. This means a mode dictates how notes interact and how melodies should move. Some theorists, like Harold S. Powers, suggest mode has a twofold sense. It can be a particularized scale or a generalized tune.

To understand how a mode functions, one must look at the relationship between pitches. A musical scale is a series of pitches in a distinct order. A mode uses this scale but adds a specific melodic character. This character is created by groups of tones within the scale. Depending on the perspective, this makes the mode either a specific scale or a unique way of playing. In Western music, this concept evolved through three distinct stages. These stages include Gregorian chant theory, Renaissance polyphonic theory, and the tonal harmonic music of the common practice period.

There are several distinct ways that modes are categorized in history. In the medieval period, the eight church modes, or Gregorian modes, were central. These modes are divided into authentic and plagal forms. They are distinguished by their ambitus, which is the range of notes, and their tenor, or reciting tone. In modern Western music, we often use the terms major and minor modes. These are actually part of the diatonic modes, specifically the Ionian and Aeolian modes. These modes are defined by their starting note, also known as the tonic.

The history of modes stretches back to Ancient Greece. Greek music theory involved three interrelated concepts: scales, tonos, and harmonia. The term tonos (plural tonoi) was used to describe a note, an interval, or a pitch. The Greeks also used different genera, or types, of scales. The diatonic genus used tones and semitones. The chromatic genus used semitones and a minor third. The enharmonic genus used a major third and two quarter-tones, called dieses.

Ancient Greek scales were named after cultural subgroups or regions. These included the Dorians, the Locrians, and people from Lydia and Phrygia. The theorist Aristoxenus studied these scales closely. He criticized earlier theorists, known as the Harmonicists, for their inaccurate diagrams. He argued their descriptions of quarter-tones lacked musical reality. Cleonides attributed thirteen tonoi to Aristoxenus. These represented a progressive transposition of the system by semitone. This allowed the scale to move through a wide range of pitches.

Modes have also been used to describe rhythm in historical contexts. In the Middle Ages, the term modus was used to describe intervals and rhythms. The Notre-Dame school used modal rhythm at the turn of the 12th century. Later, in mensural notation, modus specified the subdivision of the longa. This means it defined how long musical notes were divided. This shows that the concept of a "mode" can apply to the timing of music, not just the notes themselves.

Philosophers have long studied the significance of musical modes. Plato believed that music could influence human character and behavior. In his work, *The Republic*, he suggested that certain harmoniai could affect a person's soul. He believed soldiers should listen to Dorian or Phrygian modes to become harder and more disciplined. He warned against Lydian or Mixolydian modes, fearing they might make people too soft. Aristotle also explored how music affects ethos, or moral character.

Today, the concept of mode is part of a much broader musical landscape. While Western music focuses on major and minor, other cultures use similar systems. Examples include the Octoechos in the Byzantine system, the maqam, and the pathet. These systems show that the idea of organizing pitch into meaningful patterns is a universal human pursuit. Whether through the mathematical intervals of Pythagoras or the melodic styles of the Greeks, modes help us organize the vast world of sound into something meaningful.