Modular Vocabularies

I read an article recently describing efforts to create a faceted (yay!) music thesaurus to describe the performance archives at BYU, and the implications of this project for the development of an international music thesaurus. It’s an interesting piece. I’m all for more specialized vocabularies and think one for the field of music is sorely needed. Here’s the citation:

Spilker, John D. “Toward an International Music Thesaurus” Fontes Artis Musicae 52/1, January - March 2005: 29-44.

The mention in the article of the debate about whether to include a facet for “content subjects” which would include “extra-musical associations” (i.e., topics, things the music is “about”) gave me pause, however. Looking more closely, I also see that they propose a “philosophies and religions” facet, ask the question if “distant” terms that appear in source vocabularies as compound terms relating them to music (e.g., “astrology and music”) should be retained in any way, and copy terms from an existing instrument vocabulary into their own instrument facet. This duplication of effort bothers me a great deal. I see this phenomenon fairly often—projects that try to do everything end up doing nothing very well. LCSH does this, trying to shove everything under the heading “subject” and not making very good distinctions between what type of subjects those terms are. Even in faceted vocabularies, I see communities (like the one described in this article) try to include everything that might be needed to index material for that community. The emerging Ethnographic Thesaurus, facing an enormous task in developing a vocabulary for a very large and diverse field, shows signs of this as well, but I know the editors are considering these issues as they move forward with development. I think this would work much better if these communities focused instead on only those facets that they have particular expertise in, and “borrowed” the rest from other communities.
There’s often an assumption in the library world that a record needs to use a single “subject” vocabulary. But as we move forward, surely that’s a constraint (even if it’s only perceived) we can break out of. There’s no reason vocabulary for different facets (notice how I’m assuming a faceted, post-coordinate structure here) has to come from the same vocabulary. Let’s leave each specific vocabulary to its experts, and not try to have musicians developing terminology for religion and astronomers developing terminology for book bindings.
There are many details to work out, for example, the user implications of one vocabulary using singular forms by default and another using plural (there are standards for such things, but let’s be realistic about how many vocabularies that are otherwise useful we’d throw out of consideration because of the tense of its headings), but there are technological means for doing this. I’d hate to see an inordinate focus on the (potentially many) small challenges derail the larger, necessary, move in a more flexible direction.