When describing musical language, the first priority is to describe coherent systems of organization: modal system, tonal system, non-tonal system - or any other figuration of a pre-existing hierarchy that manifests itself through the work, but according to which the work is obliged to manifest itself.
We cannot conceive of a work that is not written according to a coherent pitch system, for example - even if we don't use this coherence as such, if we use by-products of this coherence.
(We can use a few perfect chords, the residues of a system, without having recourse to this system - like manufactured objects left behind)
In the same way, we can write without further coherence with the remains of a coherent rhythmic system. Anyone who uses value ratios is using the remnants of proportional notation.
So, voluntarily or not, consciously or unconsciously, the entire musical formulation is produced from concepts which, moreover, are forced upon us by the instruments through which we think we're transmitting the discourse - however elementary it may be.
There is a network that inserts all the data, and except in the case of absolute anarchy (hard to imagine), there is a presupposition - due to the models of realization that already exist, as well as to the means of transmission.
However, this is not enough to give cohesion to a musical work. We can only follow a musical work if we have a sense of deduction from elementary data.
The longer the work, the greater the complexity of its expression, and the greater our need for easily identifiable temporal reference points that enable our memory to select and act.
The notion of cohesion that seems to have prevailed over all others is precisely the notion of theme. The word "theme" applies to both professional and amateur musicians.
In the vocabulary of analysis, the word theme and the notions it implies are used constantly; this word is intrinsically linked to the notions of variation, development and form. Sonata themes, theme and variations, bi-thematic form, rondo form: these are all common definitions with precise implications. Without this primordial notion, it's hard to imagine years and years of readings - academic or otherwise.
But theme is also synonymous with illustration. Thus, if a theatrical artist wishes to define a piece of music for the stage, he may speak of the theme of anguish, the theme of joy, of pride... In this descendant of the Wagnerian leitmotif, we find the word theme linked to the description of a character, a type, or a concept. This is no longer a structural notion, where the theme is intended to generate a certain number of consequences in a given order, but to invent a musical figure that can be experienced as representative of such and such a psychological state according to certain codes accepted from already existing musical literature. An affective code, the rudiments of which we know only too well: low tremolos, gleaming brass, solo violin and so on. Degeneration of meaning into signaling.
Yet these two notions, extreme as they may seem to us, are linked by a profound logic of expression. It was the 19th century that overloaded with expressiveness notions that were previously, above all, symbols of order.
Of course, there was descriptive music before the 19th century - descriptive, even naive. Of course we find, at a higher level, the use of symbols in musical language: interval symbols, number symbols, formal symbols. But the symbolism of the musical idea underlies it, and remains subordinate to order and sequencing.
The theme is first and foremost a generic notion, a certain combination of intervals to be developed in accordance with a system of coordinates.
The theme has tended above all to formalize development procedures: hence its brevity, which allows systematic exploitation of its resources.
If the responsibilities of thematic organization can be expressed very briefly :
- it has tended to organize the form of discourse: fugue, bi-thematic sonata ;
- it directs the expressive impulse, and assumes the symbolism of the text: Berlioz's idée fixe, Wagner's leitmotiv;
- she summed up the moment, thus opposing the conventional rhetoric of development: Debussy ;
- it monopolized both the structures of language and the formal structures of development: Schönberg, Webern;
- it ended up dissolving the very notion from which it was born, to arrive at: everything is theme, nothing is theme, to end up with an essential relativity of thematic components.