The layered onion model
Far from being limited to the three causes of sound, the number three is is a blueprint that is found recurring throughout the Creation. According to the level of manifestation, the blueprint takes on different characteristics, but it responds to the same underlying reasoning.
We saw that at a microscopic and still in power level we have the three causes of sound. At a more macroscopic level, we find the triad of playing instrument, player, and plaid (sound). The first cause is the instrument. That is its goal, to let the instrument - i.e. the string, in case of string instruments - play. The second cause intervenes and actually causes the instrument to be played - i.e. the string to be moved. Finally, we hear the outcome of the violinist "fighting" with his instrument - i.e. sound, the third cause.
As we can see, the second cause is like a wind blowing on the string, or the impressed movement. Without it and the expansion it produces, no instrument would be played and no sound would be heard. The first and third causes share a common nature, as both tend to manifestation, concretization, solidification. The second cause is that which holds everything running and makes it work. There would be no music without it and its energy, and the instrument and the unplayed sound would remain as dead and deaf entities.
At a more macroscopic level, shifting our attention from the performer with his instrument to the entire stage, we have player, listener, and listened (music). The player aims at performing that which is listened. The listener is in the middle, coloring with his emotions that which is brought to his ear and making the listened meaningful.
If we want to include also the the composer and the public, we have composer, performer, and public. This time, it is the performer giving the interpretation to the music, which becomes implicit. Without his intervention, no music would be played.
As we can see, roles are interchangeable, depending on the extent of inclusion or manifestation we want to represent, but the concept does not change. Therefore, we could explain the model with a layered onion structure. Every time you move toward a more outer layer, you are reasoning at a more macroscopic level. The actors change, but the concept remains same. This is so true that it reflects in the overall structure of music, as we will see in the chapter on the three pillars of music.