The article is based on the hypothesis that music is a mode of organisation of the sensible world, and seeks support in the poetic and painterly works of Symbolism in order to describe it as a cross-disciplinary operator. In this context, musicality emerges as a function of « dis-iconisation », a process whereby figurative content is erased in favour of expressive content in the different arts. We then outline three aesthetic modalities for this erasure, implied in the aesthetic conflicts of the end of the 19th century : the tonal system in music, the alexandrin or 12 syllable line in French poetry, and the system of complementary colours in painting. This grounds a model which puts in relief, around the idea of musicality, and through the structure to the degree of tension and the subjectivity of the speech-act, the generative « depth » of the sensible universe.