This is far-reaching. At stake, I think, is an implicit attempt to redress the denigration of the human experience of music as it was instituted by Boethius, which has become the foundations of music-theory and compositional practice for generations to come. Most venerable in his tripartite hierarchy of music is the musica mundana (cosmic concord); second comes the musica humana (the systematicity of the body and the soul); and last, negligibly, is the musica instrumentalis (auditory, fabricated sound units, both vocal and instrumental.) This axiological positing of contemplation versus musical actuality – and foremost, versus musical handedness – coalesces with the medieval classification of knowledge and the social stratification of its agents and practices. [18]

As Bruce Holsinger has argued in a path-breaking study on the erotics of music in Medieval mysticism, the said opposition was always ambivalent and apprehensive vis-à-vis incarnational theology. [19] The ambivalence became much more explicit in the time of Leonardo, when Renaissance music theorists (Franchino Gaffurius, Johannes Tinctoris) and philosophers (foremost Marsilio Ficino) were aspiring to ratify musica instrumentalis within the traditional sanctification of musica mundana and musica humana. [20] In a way, Leonardo’s pondering about the hand of the organ-player participates in this cultural propensity, for it also endeavors to reconcile music as a metaphor with music as a lived, somatic experience. Its skeptical tone, however, suggests that contrary to his contemporaries, his half-hearted venture failed. Leonardo’s intellectual set-up was totally foreign to the concerns of Gaffurius or Ficino respectively. So, while the note in question lets transpire the anatomist’s natural philosophy, which was structured by cosmological (and hence, musical) correspondence doctrines, it also reveals the musician’s reluctance to embrace this ideational substratum with regard to his understanding of what music was all about: the mystery of its production, its impact. This is why this note is so different in spirit from his earlier one, cited above from Codex Trivulzianus. The difference holds no less than the whole story of the hand and of handedness in Leonardo.

Indeed, the note about the organ player's hand betrays a self-distancing on Leonardo's part. He himself was known as virtuoso of the lira da braccio and a composer-improvvisatore, and his musicianship was not that of the organ. This is significant, because the cultural connotations of these two instruments were diametrically opposed at the time. The organ was predominantly connected with the rituals of the public space and with the dense, learned and scripted constructions of Franco-Flemish church music. The lira, on the other hand, belonged with the indigenously Italian type of song that was melody-based, instrument-accompanied, initially and idiomatically a product of the unwritten tradition, and associated with the Orphic mythology. [21]