This subject is interesting. This article from The Guardian gives more detail and perspective on the so-called Plato code.http://www.guardian.co.uk/world/2010/jun/29/plato-mathematical-musical-code
The following paragraph caught my attention.
Believing that this pattern corresponds to the 12-note musical scale widely used by Pythagoreans, Kennedy divided the texts into equal 12ths and found that "significant concepts and narrative turns" within the dialogues are generally located at their junctures. Positive concepts are lodged at the harmonious third, fourth, sixth, eight and ninth "notes", which were considered to be most harmonious with the 12th; while negative concepts are found at the more dissonant fifth, seventh, 10th and 11th.
Even in later western musical thought, the fifth is unsettling. There is a notion called "diabolus in musica" related to the fifth. Thomas Mann used in his book Doktor Faustus: The Life of the Composer Adrian Leverkuhn As Told by a Friend. http://www.brucetaub.com/bjtnotes.htm
The interval of the tritone (diablous in musica) is particularly important in this work, especially B-natural (the "offending" pitch) to F (as well as G-sharp to D, completing the diminished seventh chord). In fact, the entire piece revolves around the pitch B and the number 12 (rhythm and duration as well as pitch and techniques taken from the twelve-tone method of Schoenberg). The piece is in three sections A, B, A' with a repeat of A' followed by a brief Coda.
The following "Author’s Note" appears at the end of Doctor Faustus:
It does not seem supererogatory to inform the reader that the form of musical composition delineated in Chapter XXII, known as the twelve-tone or row system, is in truth the intellectual property of a contemporary composer and theoretician, Arnold Schönberg. I have transferred this technique in a certain ideational context to the fictitious figure of a musician, the tragic hero of my novel. In fact, the passages of this book that deal with musical theory are indebted in numerous details to Schönberg’s Harmonielehre.
Schoenberg was reportedly upset about this, but I actually found Mann’s "layman’s" explanation of the twelve-tone system or style of strict composition to be quite wonderful in many ways. Perhaps, Schoenberg simply didn’t want to be associated with the devil.
This article on Richard Strauss also deals with the subject.http://www.npr.org/templates/story/story.php?storyId=17592220
Salome, written nine years after Zarathustra, begins very differently, in a state of volatility and flux. The first notes on the clarinet are simply a rising scale, but it is split down the middle: the first half belongs to C-sharp major, the second half to G major. This is an unsettling opening, for several reasons. First, the notes C-sharp and G are separated by the interval known as the tritone, one step narrower than the perfect fifth. (Leonard Bernstein's "Maria" opens with a tritone resolving to a fifth.) This interval has long caused uneasy vibrations in human ears; medieval scholars called it diabolus in musica, the musical devil.
It appears that Benjamin Britten used it in his opera "Death in Venice," based on Thomas Mann's novel. Link here:http://www.inst.at/trans/16Nr/07_1/hess-luettich16.htm
A more exact analysis of the musical motifs throws an even sharper light on the relationship between Aschenbach and Tadzio. Generally considered a characteristic feature of Britten's late style, the tritone (an augmented fourth, which is an interval of three whole tones) is introduced as a symbol of irresolvable conflict, of the "diabolus in musica", and as a musical metaphor for "death and the devil" [Tod und Teufel] (Karbusicky 1990: 151-178). In Death in Venice, according to Sutcliffe (1978: 97), it determines even "the entirety of motifs with which the opera begins - in Aschenbach's voice as well as in the orchestra accompaniment - and the spiritually uncertain condition besetting an increasingly unproductive poet is rendered in the music's unstable, hardly determinable tonality [den intervallischen Gesamtumfang der Motive, mit denen die Oper - in der Stimme Aschenbachs ebenso wie in der Orchesterbegleitung - beginnt und in deren labiler, kaum festlegbarer Tonalität der geistig unsichere Zustand des unfruchtbar gewordenen Dichters deutlich wird]." The close chromatic motifs are musical proof of the negative influences that bring on Aschenbach's end. They create a spirit of anxiety, which mirrors and expresses Aschenbach's inner tension, without the use of words.
How is the depiction of Aschenbach to be compared to that of Tadzio? In music, we recall, it is not the tones or single notes, but rather their relation to each other that creates something like "meaning" (Faltin 1985: 128). This applies to the depiction of the two protagonists as well. Britten's semiotic techniques in depicting Aschenbach gain their significance precisely when seen in contrast to those used to characterize Tadzio. This is also true of the composition of motifs. Aschenbach's motifs consist largely of brief chromatic intervals, whereas Tadzio's motifs are composed in larger ones. They appear more open to us, 'happier,' more relaxed. Moreover, the Tadzio motif is musically associated with the "panorama-landscape motif" (Corse 1987: 143), which tells the audience that Aschenbach relates Tadzio to nature, especially to the ocean.
It's very interesting that the effect of music on the senses and emotions can be analogized to mythological figures and symbols. Then virtuosic authors like Mann, who know their music, make it all the more fascinating.