Mode (music)

In music theory, the term mode or modus is used in a number of distinct senses, depending on context.
Its most common use may be described as a type of musical scale coupled with a set of characteristic melodic and harmonic behaviors. It is applied to major and minor keys as well as the seven diatonic modes which are defined by their starting note or tonic. Related to the diatonic modes are the eight church modes or Gregorian modes, in which authentic and plagal forms of scales are distinguished by ambitus and tenor or reciting tone. Although both diatonic and Gregorian modes borrow terminology from ancient Greece, the Greek tonoi do not otherwise resemble their medieval/modern counterparts.
Previously, in the Middle Ages the term modus was used to describe intervals, individual notes, and rhythms. Modal rhythm was an essential feature of the modal notation system of the Notre-Dame school at the turn of the 12th century. In the mensural notation that emerged later, modus specifies the subdivision of the longa.
Outside of Western classical music, "mode" is sometimes used to embrace similar concepts such as Octoechos, maqam, pathet etc..

Mode as a general concept

Regarding the concept of mode as applied to pitch relationships generally, in 2001 Harold S. Powers proposed that "mode" has "a twofold sense", denoting either a "particularized scale" or a "generalized tune", or both:
In 1792, Sir Willam Jones applied the term "mode" to the music of "the Persians and the Hindoos". As early as 1271, Amerus applied the concept to cantilenis organicis. It is still heavily used with regard to Western polyphony before the onset of the common practice period, as for example "modale Mehrstimmigkeit" by Carl Dahlhaus or "Alte Tonarten" of the 16th and 17th centuries found by Bernhard Meier.
The word encompasses several additional meanings. Authors from the 9th century until the early 18th century sometimes employed the Latin modus for interval, or for qualities of individual notes. In the theory of late-medieval mensural polyphony, modus is a rhythmic relationship between long and short values or a pattern made from them; in mensural music most often theorists applied it to division of longa into 3 or 2 breves.

Modes and scales

A musical scale is a series of pitches in a distinct order.
The concept of "mode" in Western music theory has three successive stages: in Gregorian chant theory, in Renaissance polyphonic theory, and in tonal harmonic music of the common practice period. In all three contexts, "mode" incorporates the idea of the diatonic scale, but differs from it by also involving an element of melody type. This concerns particular repertories of short musical figures or groups of tones within a certain scale so that, depending on the point of view, mode takes on the meaning of either a "particularized scale" or a "generalized tune". Modern musicological practice has extended the concept of mode to earlier musical systems, such as those of Ancient Greek music, Jewish cantillation, and the Byzantine system of octoechoi, as well as to other non-Western types of music.
By the early 19th century, the word "mode" had taken on an additional meaning, in reference to the difference between major and minor keys, specified as "major mode" and "minor mode". At the same time, composers were beginning to conceive "modality" as something outside of the major/minor system that could be used to evoke religious feelings or to suggest folk-music idioms.

Greek modes

Early Greek treatises describe three interrelated concepts that are related to the later, medieval idea of "mode": scales, tonos – pl. tonoi –, and harmonia – pl. harmoniai – this third term subsuming the corresponding tonoi but not necessarily the converse.

Greek scales

The Greek scales in the Aristoxenian tradition were:
These names are derived from ancient Greeks' cultural subgroups, small regions in central Greece, and certain Anatolian peoples . The association of these ethnic names with the octave species appears to precede Aristoxenus, who criticized their application to the tonoi by the earlier theorists whom he called the "Harmonicists". According to, he felt that their diagrams, which exhibit 28 consecutive dieses, were
Depending on the positioning of the interposed tones in the tetrachords, three genera of the seven octave species can be recognized. The diatonic genus, the chromatic genus, and the enharmonic genus. The framing interval of the perfect fourth is fixed, while the two internal pitches are movable. Within the basic forms, the intervals of the chromatic and diatonic genera were varied further by three and two "shades", respectively.
In contrast to the medieval modal system, these scales and their related tonoi and harmoniai appear to have had no hierarchical relationships amongst the notes that could establish contrasting points of tension and rest, although the mese might have functioned as some sort of central, returning tone for the melody.

''Tonoi''

The term tonos was used in four senses:
Cleonides attributes thirteen tonoi to Aristoxenus, which represent a progressive transposition of the entire system by semitone over the range of an octave between the Hypodorian and the Hypermixolydian. According to Cleonides, Aristoxenus's transpositional tonoi were named analogously to the octave species, supplemented with new terms to raise the number of degrees from seven to thirteen. However, according to the interpretation of at least three modern authorities, in these transpositional tonoi the Hypodorian is the lowest, and the Mixolydian next-to-highest – the reverse of the case of the octave species, with nominal base pitches as follows :
Ptolemy, in his Harmonics, ii.3–11, construed the tonoi differently, presenting all seven octave species within a fixed octave, through chromatic inflection of the scale degrees. In Ptolemy's system, therefore there are only seven tonoi. Pythagoras also construed the intervals arithmetically. In their diatonic genus, these tonoi and corresponding harmoniai correspond with the intervals of the familiar modern major and minor scales. See Pythagorean tuning and Pythagorean interval.

''Harmoniai''

In music theory the Greek word harmonia can signify the enharmonic genus of tetrachord, the seven octave species, or a style of music associated with one of the ethnic types or the tonoi named by them.
Particularly in the earliest surviving writings, harmonia is regarded not as a scale, but as the epitome of the stylised singing of a particular district or people or occupation. When the late-6th-century poet Lasus of Hermione referred to the Aeolian harmonia, for example, he was more likely thinking of a melodic style characteristic of Greeks speaking the Aeolic dialect than of a scale pattern. By the late 5th century BC, these regional types are being described in terms of differences in what is called harmonia – a word with several senses, but here referring to the pattern of intervals between the notes sounded by the strings of a lyra or a kithara.
However, there is no reason to suppose that, at this time, these tuning patterns stood in any straightforward and organised relations to one another. It was only around the year 400 that attempts were made by a group of theorists known as the harmonicists to bring these harmoniai into a single system and to express them as orderly transformations of a single structure. Eratocles was the most prominent of the harmonicists, though his ideas are known only at second hand, through Aristoxenus, from whom we learn they represented the harmoniai as cyclic reorderings of a given series of intervals within the octave, producing seven octave species. We also learn that Eratocles confined his descriptions to the enharmonic genus.

Philosophical ''harmoniai'' in Plato and Aristotle

In the Republic, Plato uses the term inclusively to encompass a particular type of scale, range and register, characteristic rhythmic pattern, textual subject, etc. Plato held that playing music in a particular harmonia would incline one towards specific behaviors associated with it, and suggested that soldiers should listen to music in Dorian or Phrygian harmoniai to help harden them but avoid music in Lydian, Mixolydian, or Ionian harmoniai, for fear of being softened. Plato believed that a change in the musical modes of the state would cause a wide-scale social revolution.
The philosophical writings of Plato and Aristotle include sections that describe the effect of different harmoniai on mood and character formation. For example, Aristotle stated in his Politics:
Aristotle continues by describing the effects of rhythm, and concludes about the combined effect of rhythm and harmonia :
The word ethos in this context means "moral character", and Greek ethos theory concerns the ways that music can convey, foster, and even generate ethical states.

''Melos''

Some treatises also describe "melic" composition, "the employment of the materials subject to harmonic practice with due regard to the requirements of each of the subjects under consideration" – which, together with the scales, tonoi, and harmoniai resemble elements found in medieval modal theory. According to Aristides Quintilianus, melic composition is subdivided into three classes: dithyrambic, nomic, and tragic. These parallel his three classes of rhythmic composition: systaltic, diastaltic and hesychastic. Each of these broad classes of melic composition may contain various subclasses, such as erotic, comic and panegyric, and any composition might be elevating, depressing, or soothing.
According to Thomas J. Mathiesen, music as a performing art was called melos, which in its perfect form comprised not only the melody and the text but also stylized dance movement. Melic and rhythmic composition were the processes of selecting and applying the various components of melos and rhythm to create a complete work. According to Aristides Quintilianus: