Although known primarily for his contributions to musicology and criticism, Fétis had effects on the realm of music theory as well. In 1841 he put together the first history of harmonic theory, his ''Esquisse de l'histoire de l'harmonie
. Assembled from individual articles that Fétis published in the Revue et Gazette musicale de Paris'' around 1840, the book predates
Hugo Riemann's more well known
Geschichte der Musiktheorie by fifty years. The
Esquisse, as the title implies, is a general outline rather than an exhaustive study. Fétis is attempting to show the "facts, errors, and truths" of previous theories and theorists, as he interprets them, in order to provide a solid grounding for other scholars and to prevent subsequent interpretive mistakes. Fétis' main theoretical work and the culmination of his conceptual frameworks of tonality and harmony is the ''Traité complet de la théorie et de la pratique de l'harmonie
of 1844. This book has influenced later theorists and composers including Paul Hindemith, Ernst Kurth, and Franz Liszt. In the Musik-Lexicon'' of 1882, Hugo Riemann states that "to [Fétis'] meditations we are indebted for the modern concept of tonality…he found himself emancipated from the spirit of a particular age, and able to render justice to all the various styles of music." Though some other theorists, most notably Matthew Shirlaw, have had decidedly negative views, Riemann's assessment captures the two key features of Fétis' text. Though he did not coin the term "tonality," Fétis developed the concept into its present-day form. He claimed that
"tonalité" is the primary organizing agent of all melodic and harmonic successions and that the efforts of other theorists to find the fundamental principle of music in "acoustics, mathematics, aggregations of intervals, or classifications of chords have been futile." The majority of the
Traité complet is devoted to explaining how
tonalité organizes music. The primary factor of determining tonality is the scale. It sets out the order of the succession of tones in major and minor (the only two "tonal" modes which he recognizes), the distances which separate the tones, and the resultant melodic and harmonic tendencies. Tonality is not only a governed and conditioned state, but it is a socially conditioned one. Scales are cultural manifestations, resulting from shared experience and education. Nature provides the elements of tonalité, but human understanding, sensibility, and will determine particular harmonic systems. This concept was called a "
Metaphysical principle" by Fétis, though
Carl Dahlhaus argues that the term is used in this case to denote an
anthropological, culturally relative sense in his 1990 book
Studies on the Origin of Harmonic Tonality, and theorist Rosalie Schellhous posits that the Kantian term "transcendental" might be more appropriate. In his comparative work, Fétis attempted "a new method of classifying human races according to their musical systems" following contemporary trends of social darwinism in the emerging fields of ethnology and anthropology.
Harmonic and rhythmic modulation However, if one wishes to interpret Fétis' metaphysical theory, one of his unique theoretical ideas is laid out in book 3 of the
Traité complet, that of
harmonic modulation. Fétis argues that tonality has evolved over the course of time through four distinct phases, or
ordres: • Unitonic – Resulting from
plainchant tonality, the unitonic phase consists mainly of
consonant triads with no possibility for modulation due to the lack of the
tritone between the 4th and 7th scale degrees. This phase is also referred to by Fétis as
tonalité ancienne. • Transitonic – Order which began with the introduction of the dominant 7th chord into harmonic discourse, sometime between
Zarlino and
Monteverdi. This development is also directly related to the codification of cadential systems and periodic phrase structure. • Pluritonic – Modulation is achieved through enharmonic relationships in which one note of a chord is considered the point of contact between different scales. Fétis claims that
Mozart was the first to use such modulations as a means of expression. In this order, the diminished 7th and augmented 6th chords become important as they can modulate to several different tonalities. • Omnitonic – The final phase of tonality, and one embodied for Fétis by
Wagner, where the alteration of the intervals of natural chords and modification by substitution of notes is so complex that it becomes impossible to identify the original chord. This is seen as a period of extremes, and undesirable compared to the moderately chromatic music of
Meyerbeer. Fétis later applied this same system of ordres to rhythm, "the least advanced part of music...[where] great things remain to be discovered." Though he did not publish these theories in any of his treatises, they appear in several articles for the
Revue musicale and in some lectures which had a profound impact on
Liszt. Though music had not yet made it past the first phase, Unirhythm, by Fétis' time, he argues that composers may be able to "mutate" from one meter to another within the same melodic phrase. Though Liszt may have been an open disciple of the ideas of the Omnitonic and Omnirhythmic, the influence of such thinking can perhaps be seen most clearly in the music of
Brahms, where
hemiola and mixing of time signatures is a common occurrence. =="Se i miei sospiri"==