the ocular harpsichord of louis-bertrand castel - Gewina

Castel's ocular harpsichord 57
spring, darkness, solitude, etc., and with the majority of objects? How is it possible that out of
three arts imitating nature, the most arbitrary and the least precise speaks the most forcefully
to our soul?
As a rare exception in eighteenth-century literary style, the question mark did
not conclude a rhetorical question. One of his suggested answers clearly pointed
to the later developments as described by Neubaucr and Barry: "Would it be
that [music], by showing the objects to a lesser degree, leaves more room for
our imagination ...?""^
Pointing out the exceptional ability of music to touch the human soul became
a frequently used argument against Castel's colour music after 1750. One of its
critics who used this argument was Rousseau. We can infer from a small remark
in one of Castel's books that Rousseau had visited his workshop in 1742 or 1743
and apparently had seen music in the instrument."'' Nevertheless, in his Essai
sur I'origine des langues Rousseau confirmed to have seen "this famous harpsichord,
on which it is pretended a mu.sic of colours can be played", but in the
meantime he had developed many serious arguments again.st it, putting blatantly:
There are no absurdities that physical observations have not given rise to considering the fine
arts. In the analysis of sound the same relations have been discovered as were found by the
analysis of light. Immediately this analogy has been seized upon, completely disregarding
experience and reason. The esprit de sysli'me has confounded everything, and as one did not
know how to paint for the ears, one has taken it into its head to sing to the eyes.''''
Rousseau not only called to mind the anatomical differences between eye and
ear, but he pronounced the general difference between music and any art of
colour, which Castel had thought open to manipulation, to be of the essence of
All citations from Additions pour senir d'cclaircissement a quelques endroils de la Lettre sur
les sourds et muets, in Diderot, Oemres completes, vol. 1, pp. 407^09: "ne flattcnt voire oreille que
comme I'arc-en-ciel plait a vos yeux, d'un plaisir de sensation pur et simple"; "l.a peinture montre
I'objet meme, la poesie le dccrit, la musique en excite a peine une idee; elle n'a de ressource que
dans les intervalles et la duree des sons, lit quelle analogic y a-t-il entre cettc espece de crayons
et le printemps, les tenebres, la solitude, etc., et la plupart des objets? Comment se fait-il done
que des trois arts imitateurs de la nature, celui dont I'e.xprcssion est la plus arbitraire et la moins
precise parle le plus fortement a I'ame? Serait-ce que, monlrant moins les objets, il laisse plus de
carriere a notre imagination ...?"
Castel, L'homme moral, p. 194, stating that "M. R[ousseau] ait cru autrefois voir de la
Musique dans mon Clavessin oculaire."
Rousseau, Essai, p. 169: "II n'y a sortes d'absurditcs auxquclles les observations physiques
n'aient donne lieu dans la consideration des beaux-arts. On a trouve dans I'analyse du son les
memes rapports que dans celle de la lumiere. Au.ssi-t6t on a saisi vivcmcnl cette analogic sans
s'embarrasser de I'experience et de la raison. L'esprit de sisteme a tout confondu, et faute de
savoir peindre aux oreilles on s'est avisc de chanter aux yeux. J'ai vii ce fameux clavecin sur lequel
on pretendoit faire de la musique avec des couleurs". The &.«!/ was probably written between 1755
and 1761, but only published in 1781, after Rousseau's death.